Intelligent response type temperature control nanofiber separation membrane and preparation method thereof

Abstract

The invention discloses an intelligent response type temperature control nanofiber membrane based on a metal organic framework confinement phase change material and a preparation method of the intelligent response type temperature control nanofiber membrane. The nanofiber membrane is prepared by constructing a polymer fiber substrate through electrostatic spinning, then growing a metal organic framework layer on the fiber surface in situ, and encapsulating a thermal response phase change material in a framework pore channel by using a vacuum impregnation process. The method is reasonable in preparation process design, simple and efficient, and the obtained intelligent temperature control nanofiber membrane has remarkable temperature response characteristics and excellent hydrophilicity and anti-pollution performance. The introduction of the metal organic framework material not only realizes the regulation and control of the aperture of the film, but also inhibits the migration and leakage tendency of the thermal response material in the repeated phase change process, and ensures the long-term stability of the intelligent temperature control film. The prepared intelligent response temperature control nanofiber membrane has excellent selective separation performance on different proteins while keeping high flux (pure water flux of 1500-2300 L.m <-2 >. H <-1 >). The response temperature range of the membrane material is 20-50 DEG C, the aperture change range is 10-50 nm, and the flux recovery rate is still greater than or equal to 85% after 30 times of thermal cycling. The material has important application value in the fields of intelligent separation, controllable release, self-adaptive protection and the like.

Description

Technical Field

[0001] This invention belongs to the field of separation membrane material technology, specifically relating to a smart responsive temperature-controlled nanofiber membrane based on a metal-organic framework (MOF) confined phase change material and its preparation method. This membrane material utilizes in-situ growth technology to construct an ordered porous MOF structure on the fiber surface, and then precisely loads the thermally responsive material into the pores through nanoconfinement effects. By loading the thermally responsive material into the pores of the MOF material and combining in-situ growth technology with confined loading technology, a highly responsive smart membrane material with multi-level structural synergy is successfully prepared. This material has significant application value in intelligent separation and controlled release in complex protein separation systems. Background Technology

[0002] With advancements in biomedicine and biotechnology, the demand for efficient and highly selective protein separation technologies is becoming increasingly urgent. Among numerous separation methods, membrane separation technology has attracted widespread attention due to its advantages such as ease of operation, low energy consumption, and ease of scale-up. However, traditional separation membranes still face two major challenges when dealing with complex protein systems: first, membrane fouling is a serious problem, with proteins easily and irreversibly adsorbed into the membrane channels through hydrophobic or electrostatic interactions, leading to flux decay and reduced lifetime; second, a common "flux-rejection trade-off" effect exists, making it difficult to achieve high throughput while maintaining a high rejection rate, especially for screening proteins of similar size.

[0003] To address the aforementioned issues, numerous studies have attempted to improve membranes through material modification. For example, grafting amphoteric dynamic supramoleculars, such as cyclodextrin and polydimethylsiloxane, onto the membrane surface creates supramolecular structures, combining hydrophilicity with low surface energy microdomains to create a synergistic antifouling mechanism to reduce protein adsorption (Reference: CN119215701A). While this method alleviates membrane fouling to some extent, it typically lacks environmental responsiveness and cannot achieve in-situ removal of contaminants or membrane regeneration. Regarding smart responsive membranes, thermoresponsive materials such as poly(N-isopropylacrylamide) (PNIPAM) have been introduced into membrane materials, utilizing their temperature-dependent hydrophilic / hydrophobic transitions to regulate membrane performance. Heating can cause PNIPAM segments to shrink, desorbing adsorbed proteins to achieve membrane cleaning. However, this process usually requires interrupting filtration and is completed in a separate cleaning step, failing to couple the "decontamination" and "sieving" functions within the same dynamic pore size change process, thus limiting its continuous operation efficiency and application potential. In addition, directly coating or blending thermally responsive polymers into membranes often faces problems such as slow response rate, uneven loading, and insufficient cycle stability.

[0004] In recent years, metal-organic frameworks (MOFs) have been regarded as ideal carriers of functional materials due to their regular channels and high specific surface area. Based on this, this invention proposes a cascade functionalization strategy of "in-situ growth of metal-organic frameworks - confined loading of thermally responsive materials" to construct a multi-level structure with dynamic pore size control capability on an electrospun nanofiber membrane substrate. Specifically, during the fiber forming stage, a metal source is uniformly dispersed inside the fiber, inducing in-situ growth of MOFs on the fiber surface and inside; further, the nanopores of MOFs are used as "molecular containers" to encapsulate thermally responsive media such as octadecane through a confinement effect. Under temperature stimulation, the encapsulated medium undergoes a phase transition, driving a synergistic change in the pore size between the MOF channels and the fibers, thereby achieving dynamic and reversible control of the membrane pore size. This structure not only effectively inhibits irreversible protein adsorption but also integrates membrane surface contamination removal and selective sieving into the same temperature control process, overcoming the limitations of traditional membranes in continuous operation.

[0005] In summary, this invention, through an in-situ-confined coupling modification path, has for the first time achieved precise loading and dynamic pore size control of thermally responsive media in MOF channels within nanofiber membranes. This provides a new material system and technical solution for addressing membrane fouling and the "trade-off" effect, and has significant advantages in applications requiring precise protein separation and continuous operation. Summary of the Invention

[0006] The purpose of this invention is to address the current problem of membranes being easily fouled and unable to meet the requirements of membrane separation. A smart responsive temperature-controlled nanofiber separation membrane is prepared by this invention. The nanofiber separation membrane prepared by this method has advantages such as high flux, good antifouling performance, and good selectivity for proteins of different sizes. It is suitable for membrane separation processes and can ensure excellent separation effect and long-term stable operation.

[0007] The intelligent responsive temperature-controlled nanofiber separation membrane prepared by this invention is fabricated by constructing a polymer fiber substrate through electrospinning, followed by in-situ growth of a metal-organic framework layer on the fiber surface, and then encapsulating a thermally responsive phase change material within the framework channels using a vacuum impregnation process. The process includes the following steps: Step 1): In the preparation of the spinning solution, by mass percentage, 12-15% of the film substrate, 70-82% of the solvent, 5-10% of the thermoplastic polyurethane elastomer, and 1-5% of the metal source are heated and stirred at 60-80℃ for 2-4 hours to form a homogeneous and transparent solution.

[0008] Step 2): Place the spinning solution obtained in step (1) into a high-voltage electrospinning device, control the injection pump speed to be 1.0-2.0 mL / h, and the distance between the spinneret and the receiving device to be 10-20 cm. Apply a voltage of 10-20 kV at 20-30℃ and 40%-60% humidity to form a Taylor cone and stretch the spinning solution into nanofibers. The fibers are deposited on the receiving device to form a porous fiber membrane. Then, hot press at 100-120℃ and 5-15 MPa for 2-5 min.

[0009] Step 3): Immerse the hot-pressed nanofiber membrane in a growth solution containing gallic acid ligands at a concentration of 5-15 mmol / L. React in a shaker water bath at 60-90°C for 4-12 hours to grow a gallic acid metal-organic framework layer in situ on the fiber surface.

[0010] Step 4): After vacuum pretreatment, the MOF@fiber composite membrane obtained in step (3) is immersed in molten thermally responsive material at 45-60°C for 12-24 hours to achieve loading of the thermally responsive material within the metal-organic framework channels. The residual thermally responsive material on the surface is cleaned, and the membrane is dried to obtain the intelligent temperature-controlled nanofiber membrane.

[0011] Preferably, in step 1), the membrane substrate is one of polyacrylonitrile or polyethersulfone.

[0012] Preferably, the solvent in step 1) can be one of N,N-dimethylformamide, N-methylpyrrolidone, or N,N-dimethylacetamide.

[0013] Preferably, the metal source in step 1) is one of aluminum chloride hexahydrate, zinc acetate, and ferric chloride.

[0014] Preferably, the growth solution in step 3) is a mixed solution of gallic acid in ethanol and water, wherein the volume ratio of ethanol to water is 1:1-3:1.

[0015] Preferably, the thermally responsive material in step 4) is one of octadecane or eicosane.

[0016] The present invention provides a nanoparticle-reinforced composite fiber membrane, characterized in that the nanofiber membrane exhibits a pure water flux of 1500-2300 L·m⁻¹ at a pressure of 1 bar. -2 ·h -1 It has a rejection rate of ≥99% for bovine serum albumin and ≥85% for pepsin, and has good anti-pollution properties and flux recovery rate. After 30 cycles of hot and cold, the flux recovery rate is still ≥85%.

[0017] Beneficial effects: This invention is significantly superior to existing separation membranes in terms of high selectivity, high rejection rate, antifouling properties, and long-term stability.

[0018] 1. Excellent separation performance At a pressure of 1 bar, the pure water flux is 1500-2300 L·m. -2 ·h -1 The retention rate of bovine serum albumin is ≥99%, the retention rate of gastric protein is ≥85%, and the flux recovery rate is still ≥85% after 30 cycles of hot and cold.

[0019] 2. Excellent functional layer stability and thermal response performance By employing a modification strategy combining in-situ growth and confined loading, MOFs are firmly bonded to fiber substrates. Utilizing the nanoconfinement effect, thermoresponsive materials are precisely encapsulated within the nanopores of the MOF. This ingeniously upgrades traditional passive separation or adsorption materials into actively responsive smart materials. The hydrophilic groups on the MOF result in a membrane surface contact angle ≤30°, significantly enhancing the membrane's hydrophilicity. Through the inherent properties of the thermoresponsive material, the signal of molecular changes within the confined space is efficiently amplified and converted into a signal of pore size changes in macroscopic membrane performance, successfully achieving precise pore size control.

[0020] 3. Dynamic and reversible control of membrane pore size Dynamic and reversible control of membrane pore size is achieved through temperature changes, cleverly integrating sieving and filtration as well as contaminant removal into a single process. The core mechanism is as follows: when the temperature is below the phase transition temperature of the thermally responsive material (such as octadecane), the material is in a solid state, and the membrane exhibits a large effective pore size. This not only enables high-throughput filtration and high-precision retention but also allows for membrane rinsing to remove residual contaminants from the membrane surface and pores. When the temperature rises above the phase transition point, the volume expansion and interfacial property changes caused by the phase transition generate microscopic mechanical stress within the nanoscale confinement space, significantly weakening the adsorption force of proteins. This forces the desorption of adsorbed contaminants, achieving an antifouling effect. Attached Figure Description

[0021] Figure 1 Scanning electron microscope image of nanofibers in a polyacrylonitrile-modified membrane according to Example 1 of this invention. Figure 2 Physical image of the polyacrylonitrile-modified membrane of Embodiment Six of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments.

[0023] Example 1 Step 1): Preparation of the spinning solution. The membrane substrate consists of 1.2 g polyacrylonitrile, 8.2 g N,N-dimethylformamide solvent, 0.5 g thermoplastic polyurethane elastomer, and 0.1 g aluminum chloride hexahydrate. The substrate, thermoplastic polyurethane elastomer, metal source, and solvent are heated and stirred at 60°C for 3 h to dissolve and form a transparent liquid.

[0024] Step 2): The obtained spinning solution is placed in a high-voltage electrospinning device. The injection pump speed is controlled at 1.0 mL / h, and the distance between the spinneret and the receiving device is 10 cm. A voltage of 14 kV is applied at 20℃ and 45% humidity to form a Taylor cone in the spinning solution and stretch it into nanofibers. The fibers are deposited on the receiving device to form a porous fiber membrane. Then, it is hot-pressed at 100℃ and 15 MPa for 2 min for later use.

[0025] Step 3) The hot-pressed nanofiber membrane is immersed in a growth solution containing gallic acid ligands at a concentration of 15 mmol / L and a volume ratio of ethanol to water of 2:1. The membrane is then placed in a shaker water bath at 90°C for 8 hours to grow a gallic acid metal-organic framework layer in situ on the fiber surface.

[0026] Step 4) After vacuum pretreatment, the nanofiber composite membrane obtained in step (3) is immersed in molten thermally responsive material octadecane and impregnated at 60 °C for 12 hours to achieve loading of the thermally responsive material within the metal-organic framework channels. The residual thermally responsive material on the surface is cleaned and the membrane is dried.

[0027] The heat-responsive nanofiber membrane has a pure water flux of 2200 L·m at 1 bar. -2 ·h -1 At a feed temperature of 25°C, the membrane exhibited a 99% rejection rate for bovine serum albumin and an 85% rejection rate for pepsin. When separating a pepsin solution at a feed temperature of 35°C, the membrane pore size decreased to 20 nm due to the thermal response. The rejection rate for pepsin remained at 90%. After 30 cycles of thermal cycling, the flux recovery rate was 85%.

[0028] Example 2 Step 1): Preparation of the spinning solution. The membrane substrate consists of 1.3 g polyacrylonitrile, 8.0 g N,N-dimethylformamide solvent, 0.5 g thermoplastic polyurethane elastomer, and 0.2 g aluminum chloride hexahydrate. The substrate, thermoplastic polyurethane elastomer, metal source, and solvent are heated and stirred at 70°C for 4 h to dissolve and form a transparent liquid.

[0029] Step 2): The obtained spinning solution is placed in a high-voltage electrospinning device. The injection pump speed is controlled at 1.0 mL / h, and the distance between the spinneret and the receiving device is 18 cm. A voltage of 14 kV is applied at 30℃ and 50% humidity to form a Taylor cone in the spinning solution and stretch it into nanofibers. The fibers are deposited on the receiving device to form a porous fiber membrane. Then, it is hot-pressed at 110℃ and 10 MPa for 2 min for later use.

[0030] Step 3) The hot-pressed nanofiber membrane is immersed in a growth solution containing gallic acid ligands at a concentration of 5 mmol / L and a volume ratio of ethanol to water of 1:1. The membrane is then placed in a shaker water bath at 60°C and reacted for 12 hours to grow a gallic acid metal-organic framework layer in situ on the fiber surface.

[0031] Step 4) After vacuum pretreatment, the nanofiber composite membrane obtained in step (3) is immersed in molten thermally responsive material octadecane and impregnated at 45°C for 24 hours to achieve loading of the thermally responsive material within the metal-organic framework channels. The residual thermally responsive material on the surface is cleaned and the membrane is dried.

[0032] The heat-responsive nanofiber membrane has a pure water flux of 1600 L·m at 1 bar. -2 ·h -1 At a feed temperature of 25℃, the retention rate of bovine serum albumin was 99.2%, and the retention rate of pepsin was 86%. When separating a pepsin solution at a feed temperature of 40℃, under the effect of thermal response, the membrane pore size decreased to 17 nm, and the retention rate of pepsin was 93%. After 30 cycles of thermal cycling, the flux recovery rate was 85.5%.

[0033] Example 3 Step 1): Preparation of the spinning solution. The membrane substrate consists of 1.5 g polyacrylonitrile, 8.0 g N,N-dimethylformamide solvent, 0.2 g thermoplastic polyurethane elastomer, and 0.3 g aluminum chloride hexahydrate. The substrate, thermoplastic polyurethane elastomer, metal source, and solvent are heated and stirred at 60 °C for 2 h to dissolve and form a transparent liquid.

[0034] Step 2): The obtained spinning solution is placed in a high-voltage electrospinning device. The injection pump speed is controlled at 1.0 mL / h, and the distance between the spinneret and the receiving device is 18 cm. An 18 kV voltage is applied at 30℃ and 50% humidity to form a Taylor cone in the spinning solution and stretch it into nanofibers. The fibers are deposited on the receiving device to form a porous fiber membrane. Then, it is hot-pressed at 110℃ and 10 MPa for 5 min for later use.

[0035] Step 3) The hot-pressed nanofiber membrane is immersed in a growth solution containing gallic acid ligands, with a gallic acid concentration of 10 mmol / L and a volume ratio of ethanol to water of 3:1. The membrane is then placed in a shaker water bath at 60°C and reacted for 4 hours to grow a gallic acid metal-organic framework layer in situ on the fiber surface.

[0036] Step 4) After vacuum pretreatment, the nanofiber composite membrane obtained in step (3) is immersed in molten thermally responsive material octadecane and impregnated at 60 °C for 24 hours to achieve loading of the thermally responsive material within the metal-organic framework channels. The residual thermally responsive material on the surface is cleaned and the membrane is dried.

[0037] The heat-responsive nanofiber membrane has a pure water flux of 1820 L·m at 1 bar. -2 ·h -1 At a feed temperature of 25℃, the rejection rate for bovine serum albumin was 99.3%, and the rejection rate for pepsin was 88%. Backwashing with 20℃ pure water, under thermal response, increased the membrane pore size to 50 nm, successfully removing contaminants from the membrane surface and pores. After 30 cycles of hot and cold cycling, the flux recovery rate was 87%.

[0038] Example 4 Step 1): Preparation of the spinning solution: The membrane substrate consists of 1.4 g polyacrylonitrile, 8.0 g N,N-dimethylformamide solvent, 0.2 g thermoplastic polyurethane elastomer, and 0.4 g aluminum chloride hexahydrate. The substrate, thermoplastic polyurethane elastomer, metal source, and solvent are heated and stirred at 80 °C for 4 h to dissolve and form a transparent liquid.

[0039] Step 2): The obtained spinning solution is placed in a high-voltage electrospinning device. The injection pump speed is controlled at 1.4 mL / h, and the distance between the spinneret and the receiving device is 15 cm. A voltage of 15 kV is applied at 30℃ and 50% humidity to form a Taylor cone in the spinning solution and stretch it into nanofibers. The fibers are deposited on the receiving device to form a porous fiber membrane. Then, it is hot-pressed at 100℃ and 10 MPa for 5 min for later use.

[0040] Step 3) The hot-pressed nanofiber membrane is immersed in a growth solution containing gallic acid ligands, with a gallic acid concentration of 15 mmol / L and a volume ratio of ethanol to water of 3:1. The membrane is then placed in a shaker water bath at 90°C and reacted for 12 hours to grow a gallic acid metal-organic framework layer in situ on the fiber surface.

[0041] Step 4) After vacuum pretreatment, the nanofiber composite membrane obtained in step (3) is immersed in molten thermally responsive material octadecane and impregnated at 45 °C for 24 hours to achieve loading of the thermally responsive material within the metal-organic framework channels. The residual thermally responsive material on the surface is cleaned and the membrane is dried.

[0042] The heat-responsive nanofiber membrane has a pure water flux of 2120 L·m at 1 bar. -2 ·h -1 At a feed temperature of 25℃, the retention rate of bovine serum albumin was 99.6%, and the retention rate of pepsin was 87%. When separating a pepsin solution at a feed temperature of 29℃, the membrane pore size decreased to 18 nm under the effect of thermal response, and the retention rate of pepsin was 94%. After 30 cycles of thermal cycling, the flux recovery rate was 86%.

[0043] Example 5 Step 1): Preparation of the spinning solution. The membrane substrate consists of 1.2 g polyacrylonitrile, 8.2 g N,N-dimethylformamide solvent, 0.3 g thermoplastic polyurethane elastomer, and 0.3 g aluminum chloride hexahydrate. The substrate, thermoplastic polyurethane elastomer, metal source, and solvent are heated and stirred at 80 °C for 4 h to dissolve and form a transparent liquid.

[0044] Step 2): The obtained spinning solution is placed in a high-voltage electrospinning device. The injection pump speed is controlled at 1.5 mL / h, and the distance between the spinneret and the receiving device is 15 cm. A voltage of 14 kV is applied at 30℃ and 50% humidity to form a Taylor cone in the spinning solution and stretch it into nanofibers. The fibers are deposited on the receiving device to form a porous fiber membrane. Then, it is hot-pressed at 100℃ and 12 MPa for 3 min for later use.

[0045] Step 3) The hot-pressed nanofiber membrane is immersed in a growth solution containing gallic acid ligands at a concentration of 15 mmol / L and a volume ratio of ethanol to water of 3:1. The membrane is then placed in a shaker water bath at 90°C for 8 hours to grow a gallic acid metal-organic framework layer in situ on the fiber surface.

[0046] Step 4) After vacuum pretreatment, the nanofiber composite membrane obtained in step (3) is immersed in molten eicosane, a thermally responsive material, and impregnated at 60 °C for 24 hours to achieve loading of the thermally responsive material within the metal-organic framework channels. The residual thermally responsive material on the surface is cleaned and the membrane is dried.

[0047] The heat-responsive nanofiber membrane has a pure water flux of 2300 L·m at 1 bar. -2 ·h -1 At a feed temperature of 25℃, the retention rate of bovine serum albumin was 99.4%, and the retention rate of pepsin was 89%. When separating a pepsin solution at a feed temperature of 37℃, the membrane pore size decreased to 12 nm under the effect of thermal response, and the retention rate of pepsin was 94%. After 30 cycles of thermal cycling, the flux recovery rate was still 90%.

[0048] Example 6 Step 1): Preparation of the spinning solution. The membrane substrate consists of 1.2 g polyacrylonitrile, 8.2 g N,N-dimethylformamide solvent, 0.3 g thermoplastic polyurethane elastomer, and 0.3 g zinc acetate. The substrate, thermoplastic polyurethane elastomer, metal source, and solvent are heated and stirred at 80 °C for 4 h to dissolve and form a transparent liquid.

[0049] Step 2): The obtained spinning solution is placed in a high-voltage electrospinning device. The injection pump speed is controlled at 1.5 mL / h, and the distance between the spinneret and the receiving device is 15 cm. A voltage of 14 kV is applied at 30℃ and 60% humidity to form a Taylor cone and stretch the spinning solution into nanofibers. The fibers are deposited on the receiving device to form a porous fiber membrane. Then, it is hot-pressed at 100℃ and 15 MPa for 3 min for later use.

[0050] Step 3) The hot-pressed nanofiber membrane is immersed in a growth solution containing gallic acid ligands at a concentration of 15 mmol / L and a volume ratio of ethanol to water of 3:1. The membrane is then placed in a shaker water bath at 90°C for 8 hours to grow a gallic acid metal-organic framework layer in situ on the fiber surface.

[0051] Step 4) After vacuum pretreatment, the nanofiber composite membrane obtained in step (3) is immersed in molten eicosane, a thermally responsive material, and impregnated at 45 °C for 12 hours to achieve loading of the thermally responsive material within the metal-organic framework channels. The residual thermally responsive material on the surface is cleaned and the membrane is dried.

[0052] The heat-responsive nanofiber membrane has a pure water flux of 1600 L·m at 1 bar. -2 ·h -1 At a feed temperature of 25℃, the rejection rate for bovine serum albumin was 99.3%, and the rejection rate for pepsin was 85.2%. Backwashing with 23℃ pure water, under thermal response, increased the membrane pore size to 50 nm, successfully removing contaminants from the membrane surface and pores. After 30 cycles of hot and cold treatment, the flux recovery rate was 88%.

[0053] Example 7 Step 1): Preparation of the spinning solution. The membrane substrate consists of 1.2 g polyacrylonitrile, 8.2 g N,N-dimethylformamide solvent, 0.3 g thermoplastic polyurethane elastomer, and 0.3 g ferric chloride. The substrate, thermoplastic polyurethane elastomer, metal source, and solvent are heated and stirred at 80 °C for 4 h to dissolve and form a transparent liquid.

[0054] Step 2): The obtained spinning solution is placed in a high-voltage electrospinning device. The injection pump speed is controlled at 2.0 mL / h, and the distance between the spinneret and the receiving device is 20 cm. An 18 kV voltage is applied at 24℃ and 45% humidity to form a Taylor cone in the spinning solution and stretch it into nanofibers. The fibers are deposited on the receiving device to form a porous fiber membrane. Then, it is hot-pressed at 100℃ and 15 MPa for 5 min for later use.

[0055] Step 3) The hot-pressed nanofiber membrane is immersed in a growth solution containing gallic acid ligands at a concentration of 15 mmol / L and a volume ratio of ethanol to water of 3:1. The membrane is then placed in a shaker water bath at 90°C for 8 hours to grow a gallic acid metal-organic framework layer in situ on the fiber surface.

[0056] Step 4) After vacuum pretreatment, the nanofiber composite membrane obtained in step (3) is immersed in molten eicosane, a thermally responsive material, and impregnated at 50 °C for 8 hours to achieve loading of the thermally responsive material within the metal-organic framework channels. The residual thermally responsive material on the surface is cleaned and the membrane is dried.

[0057] The heat-responsive nanofiber membrane has a pure water flux of 1880 L·m at 1 bar. -2 ·h -1 At a feed temperature of 25℃, the retention rate of bovine serum albumin was 99.6%, and the retention rate of pepsin was 90%. When separating a pepsin solution at a feed temperature of 50℃, the membrane pore size decreased to 10 nm under the effect of thermal response, and the retention rate of pepsin was 93%. After 30 cycles of hot and cold treatment, the flux recovery rate was 95%.

Claims

1. An intelligent responsive temperature-controlled nanofiber separation membrane and a method for preparing the same, characterized by, The method comprises the following steps: (1) Spinning solution preparation: according to mass percentage, 12-15% of membrane substrate, 70-82% of solvent, 5-10% of thermoplastic polyurethane elastomer and 1-5% of metal source are heated and stirred at 60-80°C for 2-4 h to form a uniform transparent solution; (2) Electrospinning: the spinning solution obtained in step (1) is placed in a high-voltage electrospinning device, the injection pump advancing speed is controlled at 1.0-2.0 mL / h, the distance between the spinneret and the receiving device is 10-20 cm, a voltage of 10-20 kV is applied in an environment of 20-30°C and 40%-60% humidity, so that the spinning solution forms a Taylor cone and is stretched into nanofibers, the fibers are deposited on the receiving device to form a porous fiber membrane, and then the nanofiber membrane is hot-pressed at 100-120°C and 5-15 MPa for 2-5 min; (3) In-situ growth of MOF layer: the hot-pressed nanofiber membrane is immersed in a growth solution containing gallic acid ligand, the concentration of gallic acid is 5-15 mmol / L; and the nanofiber membrane is placed in a shaking water bath at 60-90°C for 4-12 h, so that a gallic acid metal organic framework layer is grown in-situ on the surface of the fiber; (4) Loading of thermal responsive material: the MOF@fiber composite membrane obtained in step (3) is vacuum pretreated and then immersed in a molten thermal responsive material, and the immersion is performed at 45-60°C for 12-24 h to realize the loading of the thermal responsive material in the pores of the metal organic framework; the surface residual thermal responsive material is cleaned, and the obtained smart temperature control nanofiber membrane is dried.

2. The method of claim 1, wherein: The membrane substrate is selected from one of polyacrylonitrile and polyethersulfone.

3. The method of claim 1, wherein: The solvent is at least one of N,N-dimethylformamide, N-methylpyrrolidone and N,N-dimethylacetamide.

4. The method of claim 1, wherein: The metal source is one of aluminum chloride hexahydrate, zinc acetate and iron chloride.

5. The method of claim 1, wherein: The growth solution is a mixed solution of gallic acid in ethanol and water, and the volume ratio of ethanol to water is 1:1-3:

1.

6. The method of claim 1, wherein: The thermal responsive material is one of octadecane and eicosane.

7. The smart responsive temperature-dependent nanofiber separation membrane prepared by the method of any one of claims 1-6, characterized in that: The pure water flux was 1500-2300 L-m -2 ·h -1 The rejection rate of bovine serum albumin was ≥99%, the rejection rate of pepsin was ≥85%, the response temperature range was 20-50 °C, the pore size range was 10-50 nm, and the flux recovery rate was still ≥85% after 30 cold and hot cycles.

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