High-performance spinning suitable for hollow fiber membranes and its preparation method

Abstract

This invention discloses a high-performance spinning method for hollow fiber membranes and its preparation method, relating to the field of polymer membrane material preparation. The invention employs a reactive precursor system constructed from side-chain silanized polyarylether sulfone, a surface-silanized metal-organic framework, and a latent hydrophilic agent. Through a gradient reactive wet spinning process, after segmented air-gap initiation and pH-buffered solidification, an inorganic-organic interpenetrating network is constructed in situ using low-temperature solvothermal chemical crosslinking technology. The hydrophilic components are fixed through a dual mechanism of discrete ion anchoring and physical embedding. Combined with gradient solvent displacement and explosion-proof vacuum drying, this invention effectively solves the problems of pore collapse caused by high-temperature annealing, loss of physically blended fillers, and hydrophilicity degradation in traditional technologies, significantly improving the membrane's structural stability, mechanical strength, and long-term antifouling performance.

Description

Technical Field

[0001] This invention relates to the field of polymer membrane material preparation, and in particular to a high-performance spinning method suitable for hollow fiber membranes and its preparation method. Background Technology

[0002] Polyarylene ether sulfone (PES) and polysulfone (PSf) hollow fiber membranes are widely used in water treatment, biological separation, and gas separation due to their excellent chemical stability and mechanical properties. To further improve the separation performance and functionality of the membranes, existing technologies typically employ physical blending modification or post-treatment processes. For example, patent US5762798 discloses a method of adjusting pore structure and improving hydrophilicity by adding polyvinylpyrrolidone (PVP) or surfactants to the casting solution; patent CN112588132B proposes blending zwitterionic copolymers as additives with the film-forming polymer to impart biocompatibility to the membrane surface; furthermore, to meet the demands of use in extreme environments, patent application CN110404423A discloses a method of treating polyimide membranes with high-temperature annealing, utilizing thermally induced molecular chain rearrangement and the formation of charge-transfer complexes to significantly improve the mechanical strength and solvent resistance of the fibers. These technologies have, to a certain extent, promoted the development of high-performance hollow fiber membranes, forming the current general preparation technology system.

[0003] However, this technology still faces irreconcilable contradictions and technical bottlenecks in practical applications:

[0004] First, modification strategies based on physical blending (such as US5762798 and CN112588132B) have the inherent defect of weak binding force between additives and matrix. During long-term operation or frequent acid-base chemical cleaning (CIP) processes, functional components (such as hydrophilic agents and nanofillers) are easily precipitated from the matrix or washed away, resulting in decreased hydrophilicity of the membrane, reduced antifouling ability, and the generation of interface defects.

[0005] Secondly, although high-temperature annealing processes (such as CN110404423A) can improve mechanical properties, high temperatures can cause excessive densification and shrinkage of polymer chain segments, often at the cost of significantly sacrificing permeation flux.

[0006] Meanwhile, the drying process in traditional preparation methods is affected by capillary surface tension, which easily leads to the collapse of nanoscale micropores, resulting in the membrane's permeability in the dry state being far lower than in the wet state. Finally, attempting to introduce a highly active chemical crosslinking system to solve the above-mentioned stability problem faces challenges in process control: highly active silane components are prone to absorbing moisture and gelling at the spinneret, causing blockage, and conventional chemical reaction excitation environments (such as strongly alkaline coagulation baths) often damage the crystal structure of functional fillers (such as metal-organic frameworks), making it difficult to achieve continuous and stable preparation of high-performance hybrid hollow fiber membranes.

[0007] Therefore, there is an urgent need to develop a preparation technology that can construct a stable chemical network in situ under mild conditions, achieve both high throughput and high strength, and enable long-term anchoring of functional components. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the purpose of this invention is to provide a technical solution to address one or more problems in the prior art.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows:

[0010] A high-performance spinning solution suitable for hollow fiber membranes, wherein the high-performance spinning solution comprises the following components by weight:

[0011] 100 parts of component A, wherein component A is a modified polyarylether sulfone with a side chain containing a triethoxysilane active group.

[0012] 3-8 parts of component B, wherein component B is a metal-organic framework UiO-66-NH2 with a surface modified with a siloxane layer.

[0013] 5-10 parts of component C, wherein component C is a styrene-maleic anhydride copolymer; 350-450 parts of main solvent, wherein the main solvent is N-methylpyrrolidone; and 20-30 parts of porogen, wherein the porogen is polyvinyl glycol.

[0014] Component A was prepared by nucleophilic substitution reaction of chloromethylated polyether sulfone with 3-aminopropyltriethoxysilane in the presence of triethylamine.

[0015] Component B was prepared by an addition reaction of the metal-organic framework UiO-66-NH2 with 3-isocyanate-propyltriethoxysilane under anhydrous conditions.

[0016] Specifically, the preparation process of component A is as follows: Under dry nitrogen protection, chloromethylated polyethersulfone with a chlorine content of 1.2-1.8 mmol / g is dissolved in N,N-dimethylacetamide, triethylamine is added, the temperature is raised to 55-60°C, 3-aminopropyltriethoxysilane is added dropwise, and the reaction is carried out at a constant temperature with stirring for 12-16 hours. The amount of 3-aminopropyltriethoxysilane used is 15-25 parts by weight relative to 100 parts by weight of chloromethylated polyethersulfone, and the amount of triethylamine used is 15-20 parts by weight.

[0017] Furthermore, the preparation process of component A also includes a purification and post-treatment step: after the reaction is completed, the reaction solution is slowly poured into 5-8 times its volume of a precipitant, wherein the precipitant is an isopropanol / water mixture with a volume ratio of 8:2. The precipitate is washed with pure isopropanol until no chloride ions are detected, and then dried under vacuum at 60°C.

[0018] Specifically, the preparation process of component B is as follows: Under light-protected and anhydrous conditions, a metal-organic framework UiO-66-NH2 with a particle size of 50-100 nm is dispersed in anhydrous tetrahydrofuran, and 3-isocyanate-propyltriethoxysilane is added. The mixture is stirred and reacted at 25-40°C for 4-6 hours. The product is centrifuged and washed with anhydrous ethanol to remove unreacted free silane. Finally, it is vacuum dried at a temperature not exceeding 40°C for 12-16 hours. The weight ratio of the metal-organic framework UiO-66-NH2 to the 3-isocyanate-propyltriethoxysilane is 3-8:1-3.

[0019] Specifically, the molecular weight Mw of component C is 80,000-120,000, and the content of acid anhydride groups is greater than 20%.

[0020] A high-performance spinning method suitable for hollow fiber membranes and its preparation method, using the aforementioned high-performance spinning solution, the preparation method includes the following steps:

[0021] Step S1, Preparation of the raw solution: Under dry nitrogen protection and light-proof conditions, component B is dispersed in part of the main solvent, and then component A, component C, pore-forming agent and the remaining main solvent are added. The solution is dissolved and mixed evenly at 50°C, and obtained by vacuum degassing and filtration.

[0022] Step S2, spinning and forming: The spinning solution and core solution are co-extruded through a spinneret, and after passing through a segmented air gap region, they enter a coagulation bath to undergo phase transformation and preliminary solidification, forming nascent hollow fibers.

[0023] Step S3, Solvent thermal crosslinking: The nascent hollow fiber is placed in a sealed reaction vessel and heated to 80-85°C under the catalysis of ethanol / water mixed medium and triethylamine. 3-aminopropyltriethoxysilane is added dropwise in stages to carry out the crosslinking reaction, thereby constructing an inorganic-organic interpenetrating network and anchoring the component C.

[0024] Step S4, Drying and Shaping: After the cross-linked fibers are replaced with a gradient solvent, they are placed in an explosion-proof vacuum drying oven and dried by step temperature increase under an absolute pressure of less than 5 kPa.

[0025] Specifically, in step S2, the segmented air gap region includes a dry nitrogen protection zone with a length of 0-30 mm and a humidity of less than 5% adjacent to the spinneret outlet, and a reaction initiation zone with a length of 30-150 mm, a temperature of 35-40℃, and a relative humidity of 75%-85%. The coagulation bath is an ammonium chloride / ammonia water buffer solution with a pH of 9.0±0.2, and the coagulation bath temperature is 45-55℃.

[0026] Specifically, in step S2, the core solution consists of 80 parts by weight of N-methylpyrrolidone, 20 parts by weight of water, and 1.5 parts by weight of triethylamine. The winding speed during the spinning process is 10-20 m / min, and the draw ratio is 0.95-1.05.

[0027] Specifically, in step S2, the nascent hollow fibers are immersed in an ethanol / water mixture containing triethylamine and pre-swelled at 60°C for 1 hour; then the temperature is raised to 80-85°C, and 3-aminopropyltriethoxysilane is slowly added dropwise over 2 hours using a constant flow pump. After the addition is complete, the reaction is continued at a constant temperature for 8-10 hours.

[0028] After the reaction is complete, the temperature is reduced to below 40°C at a rate not exceeding 10°C / h and the pressure is released.

[0029] In the ethanol / water mixture, the weight ratio of ethanol to water is 80:20. Relative to 100 parts by weight of component A, the amount of triethylamine in the ethanol / water mixture is 2-3 parts by weight, and the amount of 3-aminopropyltriethoxysilane added is 0.5-1.0 parts by weight.

[0030] Specifically, in step S4, the gradient solvent replacement process is as follows: the fiber is sequentially immersed in ethanol at concentrations of 50%, 75%, and 100% for 2 hours each, followed by immersion in a 50:50 ethanol / n-hexane mixture for 1 hour, and finally immersed in n-hexane twice for 1 hour each time. The specific procedure for the stepped temperature drying is as follows: maintaining a temperature of 30°C, 40°C, and 50°C for 1 hour each.

[0031] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0032] (i) By combining a polyarylene sulfone matrix with active siloxane groups in the side chain with a metal-organic framework with a surface-modified siloxane layer, and combining a low-temperature solvothermal crosslinking process with a gradient solvent displacement drying technology, the defects of high-temperature annealing treatment leading to polymer chain densification and shrinkage and physical drying causing capillary force collapse in the prior art are overcome. Chemical locking of wet porous structure and dry retention are achieved under mild conditions, thereby endowing hollow fiber membranes with ultra-high permeation flux that is far superior to traditional heat-annealed membranes while maintaining high mechanical strength.

[0033] (ii) By simultaneously introducing reactive siloxane groups into the polymer side chain and the surface of the nanofiller, and using the co-condensation reaction in the solvothermal curing stage to construct an inorganic-organic interpenetrating network that runs through the membrane wall, the problem of interfacial peeling and loss of physically blended nanofillers in the prior art during long-term operation or chemical cleaning is fundamentally solved. This enables the hollow fiber membrane to exhibit the crosslinking characteristics of "only swelling and not dissolving" and the zero loss stability of hybrid components in the environment of strong polar solvents and frequent acid and alkali cleaning.

[0034] (III) By introducing a latent styrene-maleic anhydride copolymer as a hydrophilic precursor, and combining the discrete ion anchoring effect of aminosilane in the solvothermal stage with the physical embedding mechanism of siloxane network, the problem of traditional hydrophilic modifiers being easily precipitated from the matrix or washed away by water flow due to poor compatibility is solved. This not only endows the membrane material with permanent hydrophilicity, but also utilizes the conformational extension and coiling characteristics of the anchored carboxyl segments as the pH of the environment changes, thereby realizing intelligent responsive rejection and efficient cleaning and regeneration of organic pollutants.

[0035] (iv) By combining the humidity control of the segmented air gap environment with the synergistic effect of the pH buffer coagulation bath system, the process contradictions of easy moisture absorption and gelation blockage of the high-activity silanized spinning solution at the spinneret and easy structural collapse of the metal-organic framework during the alkaline phase transformation are solved. This ensures the rapid formation of the dense skin layer on the fiber surface and the complete preservation of the internal hybrid crystal skeleton during continuous spinning, and realizes the stable preparation of high-performance hybrid hollow fiber membranes. Attached Figure Description

[0036] Figure 1 This is a flow chart of the hollow fiber membrane preparation process in this invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and exemplary descriptions. It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes and to enable those skilled in the art to understand and read the invention. They are not intended to limit the implementation conditions of the invention. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the invention, should still fall within the scope of the technical content disclosed in this invention.

[0038] Comprehensive explanation

[0039] This invention provides a high-performance spinning method suitable for hollow fiber membranes and its preparation method. Based on the technical concept of "in-situ sol-gel chemical coupling gradient phase transformation," this method constructs an inorganic-organic interpenetrating network (IPN) in situ within the hollow fiber membrane wall through molecular design of reactive modified materials and stepwise process control. It then utilizes a dual mechanism of "discrete ion anchoring + physical network embedding" to fix the hydrophilic components, thereby solving the problems of pore collapse, filler loss, and hydrophilicity degradation in traditional membrane materials.

[0040] The technical solution of the present invention will be described in complete detail below.

[0041] I. Preparation and Modification of Core Raw Materials

[0042] The core of this invention lies in constructing a reactive polymer precursor system, which mainly includes a side-chain silanized polyarylether sulfone (component A) and a surface-silanized metal-organic framework (component B).

[0043] 1. Component A: Modified polyarylene ether sulfone (Si-g-PES) with siloxane active groups in the side chain.

[0044] Component A serves as the main framework of the membrane. By introducing triethoxysilyl groups into the side chains of polyarylethersulfone, it is endowed with the ability to undergo cross-linking reactions in subsequent processing.

[0045] 1.1 Synthesis principle

[0046] A chloromethylation-nucleophilic substitution route was employed. First, the highly reactive chloromethyl group (-CH₂Cl) of the chloromethylated polyethersulfone (CM-PES) side chain underwent a nucleophilic substitution reaction with the primary amino group (-NH₂) in 3-aminopropyltriethoxysilane (APTES), forming a secondary amine linkage, thereby attaching the silane group to the polymer backbone. Triethylamine (TEA) was introduced during the reaction as an acid-binding agent to neutralize the hydrogen chloride (HCl) generated during the substitution reaction, preventing premature hydrolysis of the silane group due to acidic catalysis by the byproducts.

[0047] 1.2 Specific preparation steps

[0048] (1) Raw material preparation: Chloromethylated polyether sulfone (CM-PES) with a chlorine content of 1.2-1.8 mmol / g is selected as the matrix resin.

[0049] (2) Reaction process: Under dry nitrogen protection, 100 parts by weight of CM-PES were fully dissolved in 400-500 parts by weight of N,N-dimethylacetamide (DMAc). Then, 15-20 parts by weight of triethylamine (TEA) were added, which was in molar excess (>1.1 times) to ensure that the generated HCl was completely neutralized. The system was heated to 55-60℃, and 15-25 parts by weight of APTES were slowly added dropwise. The reaction was carried out under constant temperature and stirring for 12-16 hours.

[0050] (3) Post-purification treatment: After the reaction is completed, the high-viscosity reaction solution is slowly poured into the precipitant. The precipitant is an isopropanol / water mixture with a volume ratio of 8:2, and its amount is 5-8 times the volume of the reaction solution. Under vigorous stirring, the polymer precipitates out in flocculent form, while the triethylamine hydrochloride (Et3N·HCl) byproduct is fully dissolved in the aqueous phase of the precipitant.

[0051] (4) Drying: Collect the precipitate and wash it repeatedly with pure isopropanol three times until no chloride ion precipitate is formed in the washing solution when tested with silver nitrate (AgNO3) solution. Finally, place the product in a vacuum drying oven at 60℃ and dry it to constant weight to obtain pure Si-g-PES.

[0052] 2. Component B: Surface-silanized MOF hybrid (Si-@UiO-66-NH2)

[0053] Component B, as an inorganic crosslinking node, is modified on the surface to enable it to form covalent bonds with the organic matrix.

[0054] 2.1 Modification Principle

[0055] The isocyanate group (-NCO) in 3-isocyanate-propyltriethoxysilane (IPTS) has extremely high electrophilic activity and can undergo an addition reaction with the amino group (-NH2) on the surface of UiO-66-NH2 to form a stable urea bond (-NH-CO-NH-), thereby introducing an active siloxane layer on the MOF surface.

[0056] 2.2 Specific preparation steps

[0057] (1) Dispersion and reaction: Under strict light-proof and anhydrous conditions, 3-8 parts by weight of UiO-66-NH2 with a particle size of 50-100nm were ultrasonically dispersed in an appropriate amount of anhydrous tetrahydrofuran (THF). 1-3 parts by weight of IPTS were added, and the mixture was stirred at 25-40℃ for 4-6 hours.

[0058] (2) Purification: The reaction product is separated by centrifugation, and Soxhlet extraction is performed with anhydrous ethanol or multiple ultrasonic washing-centrifugation cycles to completely remove unreacted free IPTS and prevent it from self-polymerizing in the spinning solution and causing gelation.

[0059] (3) Drying: Place the purified solid under vacuum drying at a temperature not exceeding 40°C for 12-16 hours to prevent the self-polymerization failure of the active groups introduced on the surface.

[0060] II. Preparation of High-Performance Spinning Solution

[0061] The preparation of spinning solutions requires strict control of ambient moisture to prevent the pre-hydrolysis and gelation of silane groups.

[0062] 1. Composition of the original solution

[0063] By weight, the spinning solution includes:

[0064] Modified matrix (component A): 100 parts Si-g-PES;

[0065] Crosslinking nodes (component B): 3-8 parts Si-@UiO-66-NH2;

[0066] Hydrophilicity regulator (component C): 5-10 parts styrene-maleic anhydride copolymer (SMA, Mw approximately 100,000, anhydride content >20%).

[0067] Main solvent: 350-450 parts N-methylpyrrolidone (NMP, water content controlled at <0.02%);

[0068] Pore-forming agent: 20-30 parts of polyethylene glycol (PEG400).

[0069] 2. Preparation process

[0070] (1) Environmental control: The entire process is carried out in a closed reactor filled with dry nitrogen gas with a dew point below -40°C.

[0071] (2) Dispersion: Component B is first ultrasonically dispersed in part of NMP solvent for 60 minutes to obtain a uniform suspension.

[0072] (3) Dissolution: Add component A, component C, pore-forming agent and remaining solvent to the suspension, heat to 50°C, and mechanically stir for 8 hours until completely dissolved.

[0073] (4) Degassing and Quality Control: The solution is allowed to stand under vacuum for degassing, and an online viscosity monitoring device is provided. At 25°C, the rotational viscosity of the stock solution must be stable within the range of 15000-25000 mPa·s. If the viscosity increase rate exceeds 5% within 1 hour, it is determined that moisture intrusion has caused pre-crosslinking and the solution cannot be used for spinning.

[0074] (5) Filtration: Before spinning, the fibers are precisely filtered through a 15-20μm stainless steel sintered mesh.

[0075] III. Gradient Reaction Wet Spinning Process

[0076] This invention employs segmented air gaps and a specific coagulation bath to achieve gradient forming of membrane structures and initiation of initial reactions.

[0077] 1. Spinning components and parameters

[0078] The spinning solution and core solution are co-extruded through a double concentric spinneret. The winding speed during the spinning process is controlled at 10-20 m / min, and the draw ratio is controlled at 0.95-1.05 (micro-relaxed state) to protect the nascent gel network.

[0079] 2. Core Fluid Composition

[0080] The core fluid consists of 80 parts by weight of NMP, 20 parts by weight of water, and 1.5 parts by weight of triethylamine. This formulation utilizes an organic base to assist in the catalytic reaction from the inner surface, thereby regulating the endothelial structure.

[0081] 3. Segmented Air Gap Environment

[0082] After the concentrate is extruded, it passes through two zones with different atmospheres:

[0083] (1) Dry protection zone: The area 0-30mm immediately adjacent to the spinneret outlet is purged with dry nitrogen gas with a humidity of less than 5%. The purpose of this zone is to create an absolutely dry environment, prevent moisture backflow from causing gel blockage on the spinneret end face, and ensure the feasibility of continuous spinning.

[0084] (2) Reaction initiation zone: 30-150 mm in length, exposed to constant temperature and humidity air at 35-40℃ and 75%-85% relative humidity. This zone utilizes high humidity to initiate rapid pre-hydrolysis of silanes on the outer surface of the fiber, forming a dense separation skin layer and improving retention performance.

[0085] 4. Coagulation bath system

[0086] The coagulation bath uses water as the matrix, with ammonium chloride / ammonia buffer added to adjust the pH to 9.0±0.2, and the temperature controlled at 45-55℃. Under these conditions, pH 9.0 is at the edge of the metastable region of UiO-66, and the contact time is extremely short (<5 seconds), which is sufficient to gently catalyze the initiation of the sol-gel reaction without destroying the crystal framework structure of MOF.

[0087] IV. Solvent thermal crosslinking and structural curing

[0088] After the nascent fibers undergo phase transformation, they need to be subjected to solvothermal treatment to construct the final inorganic-organic interpenetrating network and anchor the hydrophilic components.

[0089] 1. Solvent thermal crosslinking medium

[0090] An ethanol / water mixture with a weight ratio of 80:20 was used. 2-3 parts by weight of triethylamine (TEA) were added to the medium as an organic base catalyst, and 0.5-1.0 parts by weight of 3-aminopropyltriethoxysilane (APTES) as an anchoring agent. TEA has a boiling point of 89℃, is non-volatile at the reaction temperature, and maintains pH stability; the high proportion of ethanol effectively protects the MOF structure from hydrolysis.

[0091] 2. The solvothermal reaction process is carried out in a stainless steel sealed reactor equipped with a pressure relief valve (set pressure 0.3MPa), rupture disc and reflux condenser.

[0092] (1) Pre-swelling / activation: Immerse the fiber in a medium containing TEA and treat it at 60°C for 1 hour. At this time, the anhydride ring in SMA is hydrolyzed into carboxylate, and the fiber undergoes micro-swelling, which is conducive to the diffusion of subsequent reactants.

[0093] (2) Stepwise addition and anchoring: Heat to 80-85℃ and slowly add APTES dropwise over 2 hours using a constant flow pump. During this process, APTES acts as a "molecular nail," and its amino group forms an ionic bond (-COO) with the carboxyl group of SMA. - H3N + -R) or partial amide bonds are used to achieve discrete anchoring; at the same time, the silane end of APTES participates in network condensation. The molar ratio of APTES amino to SMA anhydride units is controlled at 1:5 to 1:10, retaining most of the carboxyl groups to provide hydrophilicity.

[0094] (3) Deep curing: After the addition is complete, the reaction is carried out at a constant temperature for 8-10 hours. During this period, the silanol groups on the side chain of component A, the silanol groups on the surface of component B, and the silane end of APTES undergo co-condensation to form a Si-O-Si inorganic network that penetrates the membrane wall, physically locking the SMA macromolecules in the network.

[0095] (4) Cooling: After the reaction is completed, cool down to below 40°C at a rate not exceeding 10°C / h and slowly release the pressure.

[0096] V. Gradient Solvent Replacement and Drying / Setting

[0097] To prevent micropore collapse caused by capillary tension during the drying process, a gradient solvent displacement and explosion-proof vacuum drying process is adopted.

[0098] 1. Gradient solvent displacement

[0099] The cross-linked fibers were sequentially immersed in 50%, 75%, and 100% ethanol solutions for 2 hours each to gradually remove moisture. They were then immersed in a 50:50 ethanol / n-hexane mixture for 1 hour for transition, and finally immersed twice in n-hexane for 1 hour each time. The extremely low surface tension of n-hexane effectively reduces the shrinkage force of the pores during drying.

[0100] 2. Explosion-proof vacuum drying

[0101] The replaced fibers were placed in an explosion-proof vacuum drying oven equipped with a solvent condensation and recovery device. Drying was performed under deep vacuum conditions with an absolute pressure of less than 5 kPa using a stepped temperature increase program: holding at 30°C, 40°C, and 50°C for 1 hour each. This process maximizes the preservation of the high porosity structure in the wet state, resulting in high-flux dry hollow fiber membranes.

[0102] VI. Performance Verification Experiments and Data Analysis

[0103] To further confirm the practical effects of the technical solution described in this invention on microstructure construction and macroscopic performance improvement, particularly to verify the construction of the inorganic-organic interpenetrating network (IPN), the chemical anchoring of hydrophilic components, and the stability of nano-hybrid nodes, this section designs a series of rigorous comparative experiments. By controlling core variables, the influence of each key component and its ratio on membrane separation performance, mechanical strength, and chemical stability is quantitatively evaluated, thereby confirming that the technical feature range defined in this invention is an optimal choice based on scientific principles.

[0104] 1. Experimental Design and Variable Setting

[0105] Based on the principles of sol-gel chemistry and the thermodynamics of polymer blending, the following three core elements that have a decisive influence on membrane structure and performance were selected as experimental variables:

[0106] Variable 1: Amount of surface-silanized MOF (component B) added

[0107] Basis for setting: Component B serves as the "hard link" in the IPN network, and its content directly determines the network's crosslinking density and resistance to compaction. According to percolation theory, the filler needs to reach a certain threshold to construct a continuous framework, but excessive amounts can lead to agglomeration defects.

[0108] Experimental gradient: The amount of component B added was set to 0 parts, 2 parts, 5 parts (preferred values ​​in the example), and 10 parts. The focus was on investigating its effect on mechanical strength and solvent swelling resistance.

[0109] Variable 2: Amount of latent hydrophilic agent SMA (component C) added

[0110] Rationale: SMA provides hydrophilicity but relies on APTES anchoring and network embedding. If the SMA exceeds the anchoring capacity, free segments will be lost; if it is insufficient, contamination resistance will be poor. This variable is used to verify the effectiveness of the "discrete anchoring + embedding" mechanism.

[0111] Experimental gradient: The amount of component C added was set to 0 parts, 3 parts, 8 parts (preferred values ​​in the example), and 15 parts. The effects on its anti-pollution (flux recovery rate) and hydrophilic long-term effect were investigated.

[0112] Variable 3: Grafting degree (chlorine content) of the modified matrix (component A)

[0113] Basis for setting: The density of siloxane groups in the side chains of component A determines the crosslinking point spacing of the organic phase. If the grafting density is too low, a dense network cannot be formed; if it is too high, excessive crosslinking shrinkage stress will lead to brittle fracture.

[0114] Experimental gradient: CM-PES synthesis component A was selected with chlorine contents of 0.8 mmol / g, 1.5 mmol / g (preferred values ​​in the examples), and 2.2 mmol / g. The effects on pure water flux (affected by pore structure) and elongation at break were investigated in detail.

[0115] 2. Performance testing methods and standards

[0116] All tests were conducted in a standard laboratory environment, in accordance with generally accepted objective testing standards.

[0117] (1) Pure water flux and rejection rate test

[0118] Test method: A cross-flow filtration device was used. The device was pre-pressurized at 0.15 MPa for 30 minutes to eliminate physical compaction, and then the pure water permeation rate was recorded at 0.10 MPa.

[0119] Basis: Refer to the industry-standard testing specifications for ultrafiltration membrane water flux and rejection rate.

[0120] Retention target: Using a 1.0 g / L bovine serum albumin (BSA, Mw=67 kDa) solution, the concentrations of the feed solution and the permeate were measured by ultraviolet spectrophotometer, and the retention rate was calculated.

[0121] (2) Mechanical performance testing

[0122] Test method: Using a universal testing machine, the tensile rate was set to 20 mm / min, and the tensile strength (cN) and elongation at break (%) of the wet membrane filament were measured.

[0123] Basis: Refer to relevant international / national standards for the determination of tensile properties of plastics.

[0124] (3) Chemical cleaning resistance and hybrid stability test

[0125] Test method: Simulate the industrial CIP process, and use 0.1M HCl and 0.1M NaOH solutions to clean the membrane module alternately for 10 cycles.

[0126] Hydrophilic stability: The changes in contact angle and BSA flux recovery rate were measured before and after cleaning.

[0127] Hybrid stability: The cleaning waste liquid was collected, and the zirconium (Zr) content was determined by inductively coupled plasma mass spectrometry (ICP-MS) to characterize the loss of MOF nodes.

[0128] (4) Solvent resistance structural stability test

[0129] Test method: Immerse the dried membrane fibers in N,N-dimethylformamide (DMF) at 60°C for 168 hours.

[0130] Swelling / Dissolution Rate: Measure the change in dry weight before and after treatment, and calculate the weight loss rate (reflecting whether dissolution has occurred) and the degree of swelling (reflecting the density of the cross-linked network).

[0131] Basis: Refer to the relevant standards for determining the resistance of polymer materials to liquid chemical reagents.

[0132] 3. Analysis of Experimental Results (Expected)

[0133] Effect of component B: It is expected that in the range of 0-5 parts, as the MOF increases, the tensile strength and solvent resistance of the membrane will be significantly improved, and the flux will increase due to the MOF pore effect; when it reaches 10 parts, the rejection rate may decrease due to defects caused by agglomeration, and the strength will no longer improve.

[0134] Effect of component C: It is expected that in the range of 0-8 parts, the antifouling ability will increase linearly with the increase of SMA; after exceeding 10 parts, due to the saturation of the anchoring point, the flux recovery rate after cleaning will no longer increase, and there may be a phenomenon of high flux in the early stage but decay due to SMA loss after operation.

[0135] Effect of component A: A grafting degree of 1.5 mmol / g is expected to achieve the best balance between flux and strength; the 0.8 mmol / g group may partially dissolve in DMF; the 2.2 mmol / g group may have low flux and brittle fibers due to excessive crosslinking shrinkage.

[0136] Exemplary Description

[0137] Because the technical solution of this invention involves the construction of a complex organic-inorganic hybrid network and the synergistic effect of multiple reaction mechanisms, in order to objectively and comprehensively verify the rationality and technical advantages of the defined ranges of key components and process parameters in this invention, this specification specifically selects ten representative experimental groups as examples for demonstration. The design of these ten examples strictly follows the principle of controlled variables, covering preferred embodiments within the scope of this invention (Examples 1-5), comparative embodiments exceeding the defined range (Examples 6-9), and a blank control group using existing technology (Example 10). By comparing the differences in pure water flux, mechanical strength, and antifouling performance among the groups, the inventiveness and practicality of the technical solution of this invention are strongly demonstrated. Specific Implementation

[0139] Example 1

[0140] This embodiment provides a high-performance spinning method suitable for hollow fiber membranes and its preparation method. The specific steps are as follows:

[0141] 1. Raw material preparation

[0142] Preparation of Component A: Under dry nitrogen protection, 100 parts of chloromethylated polyether sulfone (CM-PES) with a chlorine content of 1.2 mmol / g were dissolved in 400 parts of DMAc, 15 parts of triethylamine (TEA) were added, the temperature was raised to 55℃, and 15 parts of 3-aminopropyltriethoxysilane (APTES) were added dropwise. The reaction was carried out at a constant temperature for 12 hours. The reaction solution was precipitated with isopropanol / water (8:2), washed, and dried under vacuum at 60℃ to obtain side-chain silanized modified polyarylene ether sulfone (Si-g-PES).

[0143] Preparation of component B: Under light-protected and anhydrous conditions, 3 parts of UiO-66-NH2 with a particle size of 50 nm were dispersed in THF, and 1 part of 3-isocyanate-propyltriethoxysilane (IPTS) was added. The reaction was carried out at 25 °C for 4 hours. After washing with anhydrous ethanol to remove free silane, the product was dried under vacuum at 40 °C for 12 hours to obtain a surface-silanized MOF (Si-@UiO-66-NH2).

[0144] Component C: Styrene-maleic anhydride copolymer (SMA) with a molecular weight Mw of 80,000-120,000 and an anhydride content of 25%.

[0145] 2. Preparation of spinning solution

[0146] Under dry nitrogen protection and light-proof conditions with a dew point below -40°C, 3 parts of component B were first ultrasonically dispersed in 80 parts of NMP for 60 minutes; then 100 parts of component A, 5 parts of component C, 20 parts of polyethylene glycol (PEG400), and 320 parts of NMP (total solvent 400 parts) were added, and the mixture was stirred and dissolved at 50°C for 8 hours. After vacuum degassing and filtration through a 15μm sintered mesh, the rotational viscosity at 25°C was monitored online and found to be 18500 mPa·s, thus obtaining a high-performance spinning solution.

[0147] 3. Spinning and forming

[0148] The above-mentioned spinning solution and core solution (80 parts NMP + 20 parts water + 1.5 parts TEA) were co-extruded through a double concentric spinneret. During spinning, the nascent fibers first passed through a dry nitrogen protection zone with a length of 30 mm and a humidity of <5% adjacent to the spinneret exit, and then entered a reaction initiation zone with a length of 100 mm, a temperature of 35℃, and a relative humidity of 75%. Next, they entered a phase inversion and shaping bath in an ammonium chloride / ammonia water buffer solution with a temperature of 45℃ and a pH of 9.0. The winding speed was 15 m / min, and the draw ratio was 1.0.

[0149] 4. Solvent thermal crosslinking

[0150] The nascent fibers were placed in a sealed reactor, and an ethanol / water (80:20) mixture and 2 parts of TEA were added. Pretreatment was carried out at 60°C for 1 hour. The temperature was then raised to 80°C, and 0.5 parts of APTES were slowly added dropwise over 2 hours using a constant flow pump. After the addition was complete, the reaction was maintained at this temperature for 8 hours. After the reaction was completed, the temperature was lowered to below 40°C at a rate of 5°C / h, and the pressure was released.

[0151] 5. Drying and shaping

[0152] The cross-linked fibers were sequentially replaced with 50%, 75%, and 100% ethanol (2 hours each), followed by a transitional replacement with ethanol / n-hexane (50:50) for 1 hour, and finally replaced twice with n-hexane (1 hour each). The fibers were then placed in an explosion-proof vacuum drying oven and dried at an absolute pressure of 2 kPa, with temperature increases of 30℃, 40℃, and 50℃ (1 hour each) to obtain the final product.

[0153] Example 2

[0154] The only difference between this embodiment and Example 1 is the variable parameters: the amount of component B (Si-@UiO-66-NH2) added is 5.5 parts, the amount of component C (SMA) added is 7.5 parts, and the chlorine content of the raw material CM-PES in component A is 1.5 mmol / g. The remaining steps, process conditions, and parameters are exactly the same as in Example 1.

[0155] Example 3

[0156] The only difference between this embodiment and Example 1 is the variable parameters: the amount of component B added is 8 parts, the amount of component C added is 10 parts, and the chlorine content of the raw material CM-PES for component A is 1.8 mmol / g. The remaining steps, process conditions, and parameters are exactly the same as in Example 1.

[0157] Example 4

[0158] The only difference between this embodiment and Example 1 is the variable parameters: the amount of component B added is 4.2 parts, the amount of component C added is 6 parts, and the chlorine content of the raw material CM-PES for component A is 1.4 mmol / g. All other steps, process conditions, and parameters are exactly the same as in Example 1.

[0159] Example 5

[0160] The only difference between this embodiment and Example 1 is the variable parameters: the amount of component B added is 7 parts, the amount of component C added is 9 parts, and the chlorine content of the raw material CM-PES for component A is 1.6 mmol / g. All other steps, process conditions, and parameters are exactly the same as in Example 1.

[0161] Example 6

[0162] The only difference between this embodiment and Embodiment 1 is the variable parameter: the amount of component B added is 1 part (below the limit specified in this invention). The remaining steps, process conditions, and parameters are exactly the same as in Embodiment 2.

[0163] Example 7

[0164] The only difference between this embodiment and Embodiment 1 is the variable parameter: the amount of component B added is 12 parts (exceeding the limit of this invention). The remaining steps, process conditions, and parameters are exactly the same as in Embodiment 2.

[0165] Example 8

[0166] The only difference between this embodiment and Example 1 is the variable parameter: the amount of component C added is 2 parts (below the limit of this invention). The remaining steps, process conditions and parameters are exactly the same as in Example 2.

[0167] Example 9

[0168] The only difference between this embodiment and Example 1 is the variable parameter: the chlorine content of component A, raw material CM-PES, is 0.8 mmol / g (below the limit specified in this invention). All other steps, process conditions, and parameters are exactly the same as in Example 2.

[0169] Example 10

[0170] This example is a blank control group prepared using existing technology.

[0171] Preparation process: 100 parts of ordinary polyethersulfone (PES) were dissolved in 400 parts of NMP, and 20 parts of PEG400 were added to prepare the casting solution. Dry-wet spinning was used with an air gap height of 100 mm (normal air environment), and the coagulation bath was 45℃ pure water. After washing, the nascent fibers were placed in a muffle furnace for high-temperature annealing: the temperature was increased to 300℃ at a rate of 5℃ / min, held for 1 hour, and then allowed to cool naturally. No chemical crosslinking, MOF addition, or SMA anchoring steps were involved.

[0172] To visually demonstrate the effectiveness of the technical solution of this invention, performance tests were conducted on the hollow fiber membrane products prepared in the above ten sets of embodiments. The test object was the final product—hollow fiber membrane filaments. Three key performance indicators were selected:

[0173] Pure water flux: Characterizes the permeation performance of the membrane (unit: L / m) 2 ·h·bar).

[0174] Tensile strength: Characterizes the mechanical properties of a membrane (unit: MPa).

[0175] Flux recovery rate: Characterizes the membrane's antifouling and regeneration capabilities after BSA protein contamination washing (unit: %).

[0176] Overall score calculation formula:

[0177] .

[0178] Table 1. Statistical Table of Relevant Data for Each Embodiment

[0179]

[0180] Based on the test results of the above embodiments, through a comprehensive evaluation of the hollow fiber membranes in terms of separation performance, mechanical strength, and antifouling ability, especially by combining a weighted scoring mechanism for quantitative comparison, the nonlinear regulatory law of the core components and their proportions on the final membrane material performance can be clearly revealed. The following will analyze in detail the performance trends presented by the experimental data and their underlying causes from the perspective of microscopic molecular structure and physicochemical mechanisms.

[0181] Analysis of Experimental Results

[0182] I. Regulation Mechanism of Mechanical and Permeability Properties by Inorganic-Organic Interpenetrating Network Integrity

[0183] By comparing experimental groups with different amounts of metal-organic frameworks (MOFs), it can be found that when the amount of MOF is within the optimal range, the tensile strength and pure water flux of the membrane fibers both reach a high level, and the overall score is significantly higher.

[0184] From a molecular level perspective, surface-silanized MOFs are no longer simply physical fillers, but rather participate in the construction of inorganic-organic interpenetrating networks (IPNs) as multifunctional crosslinking nodes. Within a preferred range, MOF particles are uniformly dispersed in the polymer matrix, co-condensing with the silanol groups of the polymer side chains through surface siloxane bonds, forming a microstructure similar to "reinforced concrete." This rigid inorganic framework effectively supports the membrane pore structure, preventing capillary collapse during the drying process. Thus, while significantly improving mechanical strength, it retains high porosity in the wet state, achieving a simultaneous increase in flux and strength.

[0185] However, when the MOF addition is too low, a continuous percolation network cannot be formed within the system, resulting in a weak hybridization enhancement effect and a lack of sufficient inorganic nodes to support the pores. This leads to membrane shrinkage during drying or solvent resistance tests, resulting in both low strength and low flux. Conversely, when the MOF addition exceeds the threshold, nanoparticles tend to aggregate, leading to unbonded microdefects at the organic-inorganic interface. These defects become stress concentration points during stretching, causing a sharp decrease in mechanical strength. Simultaneously, excessive filler occupies the free volume of the polymer chains, increasing mass transfer resistance and impairing separation performance.

[0186] II. The Impact of the Synergistic Mechanism of Discrete Anchoring and Physical Embedding on Anti-Pollution Performance

[0187] By comparing experimental groups with different amounts of hydrophilic modifier (SMA), it can be seen that as the SMA content increases, the membrane flux recovery rate first rises rapidly and then tends to level off, and the best hydrophilic long-lasting effect is obtained within the optimal range.

[0188] The underlying reason lies in the dual fixation mechanism of "discrete ion anchoring + network embedding" employed in this invention. Within a preferred range, the amount of introduced aminosilane (APTES) reaches thermodynamic equilibrium with the amount of anhydride / carboxyl groups on the SMA segments. APTES, acting as "molecular nails," discretely anchors the SMA segments to the network framework through ionic bonds or partial chemical bonds, while the resulting Si-O-Si network physically locks the SMA macromolecules within the grid. This structure not only restricts the loss of hydrophilic polymers under water erosion but also retains the mobility of most of its free carboxyl groups, allowing them to undergo conformational inversion with changes in environmental pH, thereby achieving highly efficient anti-fouling cleaning.

[0189] When the amount of SMA added is insufficient, the density of hydrophilic groups on the membrane surface does not reach the critical value for forming a continuous hydration layer, causing proteins to easily adsorb onto the exposed areas of the hydrophobic matrix, resulting in low washing and recovery efficiency. Conversely, when the amount of SMA added is significantly excessive, due to the limited number of anchoring sites (APTES), excess SMA segments cannot be effectively fixed. These free hydrophilic components will gradually precipitate from the membrane or be eluted during long-term operation. Although the hydrophilicity is acceptable initially, it will lead to unstable changes in membrane porosity, and the contribution to improving overall performance will exhibit diminishing marginal returns.

[0190] III. Thermodynamic Locking Effect of Reactive Precursor Grafting Degree on Microporous Structure

[0191] Comparison of matrix experimental groups with different chlorine contents (i.e. silane grafting degree) shows that the density of active groups in the matrix side chains is the material basis for determining the stability of the final membrane structure.

[0192] Within a preferred grafting degree range, the solvothermal crosslinking process can induce the formation of a moderately dense crosslinked network between polymer chains. This network is "frozen" by chemical bonds in the solvent-swollen state. During the subsequent gradient drying process, even if the solvent evaporates, the rigid chemical bonds can resist the relaxation and collapse of polymer chain segments, thereby permanently preserving the open microporous structure in the wet state to the dry state, exhibiting extremely high pure water flux and excellent resistance to solvent swelling.

[0193] If the grafting density is too low, the resulting cross-linked network is too sparse, and the molecular weight between the cross-linking points is too large. This leads to excessively high network flexibility, making it unable to effectively resist capillary contraction forces, causing micropore collapse, a significant decrease in flux, and a tendency to swell severely or even partially dissolve in strong solvents. Conversely, if the grafting density is too high, the cross-linking reaction rate during solvothermal processes is too fast and the cross-linking density is too high, causing the network to shrink rapidly and generate huge internal stresses. This not only closes off some effective pores, leading to a decrease in flux, but also makes the fiber matrix brittle and significantly reduces its mechanical toughness.

[0194] IV. Comprehensive Evaluation Conclusion

[0195] In summary, while the blank control group (using traditional high-temperature annealing) achieved a certain level of mechanical strength, its pore structure underwent severe densification and collapse during heat treatment due to the lack of chemical cross-linking support, resulting in a flux far lower than that of the embodiments of this invention. In contrast, the preferred embodiments of this invention, through precise control of the inorganic node content, hydrophilic component ratio, and matrix reactivity, constructed a microscopically perfect inorganic-organic interpenetrating network with minimal defects, achieving a ternary synergy of mechanical enhancement, porosity maintenance, and long-lasting hydrophilicity. This demonstrates the significant advantages of this technical solution in addressing the bottleneck problem in the preparation of high-performance hollow fiber membranes.

[0196] Specific work process

[0197] Please refer to Figure 1 The high-performance hollow fiber membrane preparation process of this invention begins with the construction of a core reactive precursor, a stage that activates an inert polymer and an inorganic framework and endows them with chemical reaction potential. First, under strict dry nitrogen protection, active silane groups are grafted onto the polyarylethersulfone backbone via a nucleophilic substitution reaction: chloromethylated polyethersulfone is dissolved in a solvent, and under the neutralizing effect of triethylamine as an acid-binding agent, the highly reactive chloromethyl side chain undergoes nucleophilic attack on the primary amino group of 3-aminopropyltriethoxysilane, losing hydrogen chloride and generating a secondary amine linker bond, thereby suspending a large number of reactive triethoxysilane groups on the polymer backbone; after precipitation and washing to remove triethylamine hydrochloride byproducts, a pure reactive matrix is ​​obtained. Meanwhile, the metal-organic framework UiO-66-NH2 undergoes surface chemical modification in an anhydrous and light-protected environment. The isocyanate group in 3-isocyanate-propyltriethoxysilane electrophilically attacks the amino group on the MOF surface, forming a stable urea bond through an addition reaction. The active silane layer is covalently "grown" on the surface of the inorganic node, and the free modifier is removed by Soxhlet extraction, thus completing the activation of the inorganic crosslinking node.

[0198] The process then proceeds to the preparation and homogenization of the reactive spinning solution, a process that pre-assembles the reactive matrix, activated crosslinking nodes, and latent hydrophilic agent at the molecular scale. Surface-activated MOF particles are first monodispersed in a partial solvent using high-frequency ultrasound, and then blended and dissolved with reactive polyarylene ether sulfone, styrene-maleic anhydride copolymer, and a porogen at a constant temperature. During this process, the components form a homogeneous system in the solvent; the styrene-maleic anhydride copolymer exists stably in a hydrophobic anhydride state, while the reactive matrix and activated MOF remain chemically quiescent. After vacuum degassing and precision filtration, a spinning solution with high reactive potential is formed.

[0199] The spinning stage is a simultaneous process of physical phase transformation and chemical reaction initiation. The dopant solution and a core solution containing an organic base catalyst are co-extruded. The nascent fiber first passes through a dry nitrogen protection zone to prevent premature gelation at the spinneret end face, then enters a high-humidity reaction initiation zone. The silanyl groups on the fiber's outer surface absorb moisture from the air and undergo rapid pre-hydrolysis, generating silanol groups which then undergo preliminary condensation to form a dense skin structure. Next, the fiber enters a coagulation bath containing an ammonium chloride / ammonia buffer system. While phase transformation induces pore formation, the weakly alkaline environment gently catalyzes the initiation of the sol-gel reaction, causing the inorganic and organic components within the fiber wall to begin preliminary cross-linking and shaping.

[0200] The final structural curing and functionalization were achieved through solvothermal crosslinking and gradient drying. Nascent fibers were placed in an ethanol / water mixture containing an organic base catalyst and an aminosilane anchoring agent. Under heating and solvent swelling conditions, all silane groups within the system—including polymer side chains, MOF surfaces, and the silane ends of the free anchoring agent—underwent deep co-condensation reactions, constructing a rigid Si-O-Si inorganic network that penetrates the membrane wall, firmly welding the MOF nodes to the polymer backbone. Simultaneously, the anhydride rings in the styrene-maleic anhydride copolymer under alkaline conditions underwent ring-opening hydrolysis to form carboxyl groups, which then reacted with the aminosilane anchoring agent diffused into the pores through acid-base salt formation or amidation reactions. One end of the carboxyl group held the hydrophilic segment via ionic or covalent bonds, while the silane group at the other end incorporated into the inorganic network, thus permanently anchoring the hydrophilic component to the backbone. Finally, through gradient solvent replacement from ethanol to n-hexane, the high-tension water in the channels is gradually replaced by low-tension solvent. Under the stepwise heating in an explosion-proof vacuum environment, the solvent evaporates without the generation of capillary contraction force, thus completely preserving the fluffy interpenetrating network structure in the wet state into the dry finished product.

[0201] The technical features described above can be combined in any way. For the sake of brevity, not all possible combinations of the technical features described above are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A high-performance spinning solution suitable for hollow fiber membranes, characterized in that: The high-performance spinning solution comprises the following components by weight: 100 parts of component A, wherein component A is a modified polyarylene ether sulfone with a side chain containing a triethoxysilane active group; 3-8 parts of component B, wherein component B is a metal-organic framework UiO-66-NH2 with a surface modified with a siloxane layer; 5-10 parts of component C, wherein component C is a styrene-maleic anhydride copolymer; 350-450 parts of main solvent, wherein the main solvent is N-methylpyrrolidone; and 20-30 parts of porogen, wherein the porogen is polyvinyl glycol; Component A was prepared by a nucleophilic substitution reaction of chloromethylated polyethersulfone with 3-aminopropyltriethoxysilane in the presence of triethylamine. Component B was prepared by an addition reaction of the metal-organic framework UiO-66-NH2 with 3-isocyanate-propyltriethoxysilane under anhydrous conditions. The high-performance spinning solution is used to prepare hollow fiber membranes by a method comprising the following steps: The spinning solution and core solution are co-extruded, and after passing through the air gap region, they enter the coagulation bath to undergo phase transformation and preliminary solidification, forming nascent hollow fibers. The nascent hollow fibers were heated in a mixed medium and with a catalyst, and 3-aminopropyltriethoxysilane was added dropwise to carry out a solvothermal crosslinking reaction. After the cross-linked fibers are replaced with gradient solvents, they are dried under vacuum to obtain a hollow fiber membrane.

2. The dope according to claim 1, wherein The preparation process of component A is as follows: under dry nitrogen protection, chloromethylated polyethersulfone with a chlorine content of 1.2-1.8 mmol / g is dissolved in N,N-dimethylacetamide, triethylamine is added, the temperature is raised to 55-60℃, 3-aminopropyltriethoxysilane is added dropwise, and the reaction is stirred at a constant temperature for 12-16 hours; wherein, relative to 100 parts by weight of chloromethylated polyethersulfone, the amount of 3-aminopropyltriethoxysilane is 15-25 parts by weight, and the amount of triethylamine is 15-20 parts by weight.

3. The dope according to claim 2, wherein The preparation process of component A also includes a purification and post-treatment step: after the reaction is completed, the reaction solution is slowly poured into 5-8 times the volume of a precipitant, wherein the precipitant is an isopropanol / water mixture with a volume ratio of 8:2; the precipitate is washed with pure isopropanol until no chloride ions are detected, and then dried under vacuum at 60°C.

4. The spinning solution as described in claim 1, characterized in that, The preparation process of component B is as follows: under light-proof and anhydrous conditions, metal-organic framework UiO-66-NH2 with a particle size of 50-100 nm is dispersed in anhydrous tetrahydrofuran, and 3-isocyanate-propyltriethoxysilane is added. The mixture is stirred and reacted at 25-40°C for 4-6 hours. The product is separated by centrifugation and washed with anhydrous ethanol to remove unreacted free silane. Finally, it is vacuum dried at a temperature not exceeding 40°C for 12-16 hours. The weight ratio of the metal-organic framework UiO-66-NH2 to the 3-isocyanate-propyltriethoxysilane is 3-8:1-3.

5. The spinning solution as described in claim 1, characterized in that: The molecular weight (Mw) of component C is 80,000-120,000, and the content of acid anhydride groups is greater than 20%.

6. A method for preparing hollow fiber membranes, using the high-performance spinning solution as described in any one of claims 1 to 5, characterized in that, The preparation method includes the following steps: Step S1, Preparation of the raw solution: Under dry nitrogen protection and light-proof conditions, component B is dispersed in part of the main solvent, and then component A, component C, pore-forming agent and the remaining main solvent are added. The solution is dissolved and mixed evenly at 50°C, and obtained by vacuum degassing and filtration. Step S2, spinning and forming: The spinning solution and core solution are co-extruded through a spinneret, and after passing through a segmented air gap region, they enter a coagulation bath to undergo phase transformation and preliminary solidification to form nascent hollow fibers; Step S3, Solvent thermal crosslinking: The nascent hollow fiber is placed in a closed reaction vessel and heated to 80-85°C under the catalysis of ethanol / water mixed medium and triethylamine. 3-aminopropyltriethoxysilane is added dropwise in steps to carry out the crosslinking reaction, constructing an inorganic-organic interpenetrating network and anchoring the component C. Step S4, Drying and Shaping: After the cross-linked fibers are replaced with a gradient solvent, they are placed in an explosion-proof vacuum drying oven and dried by step temperature increase under an absolute pressure of less than 5 kPa.

7. The preparation method according to claim 6, characterized in that: In step S2, the segmented air gap region includes a dry nitrogen protection zone with a length of 0-30 mm and a humidity of less than 5% adjacent to the spinneret outlet, and a reaction initiation zone with a length of 30-150 mm, a temperature of 35-40℃, and a relative humidity of 75%-85%; the coagulation bath is an ammonium chloride / ammonia water buffer solution with a pH of 9.0±0.2 and a coagulation bath temperature of 45-55℃.

8. The preparation method according to claim 6, characterized in that: In step S2, the core liquid is composed of 80 parts by weight of N-methylpyrrolidone, 20 parts by weight of water and 1.5 parts by weight of triethylamine; the winding speed during the spinning process is 10-20 m / min and the draw ratio is 0.95-1.

05.

9. The preparation method according to claim 6, wherein step S3 is specifically performed as follows: The nascent hollow fibers were immersed in an ethanol / water mixture containing triethylamine and pre-swelled at 60°C for 1 hour. Then the temperature was raised to 80-85°C and 3-aminopropyltriethoxysilane was slowly added dropwise over 2 hours using a constant flow pump. After the addition was complete, the reaction was continued at a constant temperature for 8-10 hours. After the reaction is complete, cool down to below 40°C at a rate not exceeding 10°C / h and release the pressure; in, The weight ratio of ethanol to water in the ethanol / water mixture is 80:20; relative to 100 parts by weight of component A, the amount of triethylamine in the ethanol / water mixture is 2-3 parts by weight, and the amount of 3-aminopropyltriethoxysilane added is 0.5-1.0 parts by weight.

10. The preparation method according to claim 6, characterized in that, In step S4, the gradient solvent replacement process is as follows: the fiber is sequentially immersed in ethanol with concentrations of 50%, 75%, and 100% for 2 hours each, then immersed in a 50:50 ethanol / n-hexane mixture for 1 hour, and finally immersed in n-hexane for 1 hour each time; the specific procedure for the stepwise temperature-increasing drying is as follows: the fiber is maintained at three temperature stages of 30℃, 40℃, and 50℃ for 1 hour each.

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