A method for preparing high-strength and super-hydrophilic nanofiber membranes by co-crystallization and applications thereof
Patent Information
- Application Number
- CN202611259491.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-19
- Publication Date
- 2026-09-25
AI Technical Summary
[0003]本发明要解决现有油水分离纳米纤维膜在高乳化水包油体系中易发生膜污染和通量衰减、纤维间结合强度不足、亲水改性组分结合不牢以及耐化学介质稳定性不足的问题，进而提供一种通过共结晶制备高强度及超亲水纳米纤维膜的方法及其应用
[0016]本发明通过在半结晶工程塑料中预分散COFs、MOFs和TiO2等结晶性纳米颗粒作为生长种子，经静电纺丝制成含晶体生长种子的纳米纤维膜，再通过水热反应使目标晶体在纤维表面及纤维间孔道内壁原位生长为纳米阵列。利用半结晶工程塑料的晶区、引入结晶性纳米颗粒的晶区以及非晶区链段之间的相互作用，提高纤维搭接点的结合稳定性；后续热压结晶工艺进一步促进半结晶工程塑料链段取向与晶区完善，从而提升纤维膜的整体力学性能。
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic polymer composite materials technology. Background Technology
[0002] With the acceleration of industrial development and urbanization, the discharge of oily wastewater has increased dramatically, posing a serious threat to the aquatic environment and ecosystems. Membrane separation technology has shown application potential in the field of oil-water separation due to its advantages such as high separation efficiency, low energy consumption, and ease of integration. Semi-crystalline engineering plastics such as polyvinylidene fluoride (PVDF), polysulfone (PSU), polyethersulfone (PES), and polyether ether ketone (PEEK) generally have good mechanical strength, thermal stability, and processing performance, making them suitable as matrix materials for durable separation membranes. However, existing polymer separation membranes are prone to membrane fouling in highly emulsified oil-in-water systems, resulting in a decrease in permeate flux. Some electrospun polymer nanofiber membranes are limited by the bonding strength of fiber overlap points and interfacial stability, and the hydrophilic modification layer is prone to detachment. The overall mechanical stability and resistance to acids, alkalis, and organic solvents still need to be improved, making it difficult to simultaneously meet the long-term and high-efficiency separation requirements of highly emulsified oil-water systems. Summary of the Invention
[0003] This invention aims to address the problems of existing oil-water separation nanofiber membranes, such as membrane fouling and flux decline, insufficient inter-fiber bonding strength, weak bonding of hydrophilic modified components, and insufficient stability against chemical media, in highly emulsified oil-in-water systems. It further provides a method for preparing high-strength and superhydrophilic nanofiber membranes through co-crystallization and its application.
[0004] A method for preparing high-strength and superhydrophilic nanofiber membranes by co-crystallization, comprising the following steps:
[0005] I. Preparation of nanofiber membranes containing crystal growth seeds:
[0006] ① At room temperature, semi-crystalline engineering plastic is mixed with an organic solvent to obtain a semi-crystalline engineering plastic solution;
[0007] ② The semi-crystalline engineering plastic solution is mixed with crystalline nanoparticles to obtain the casting solution;
[0008] ③ The casting solution is electrospun to obtain a semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane;
[0009] II. Preparation of composite nanofiber membranes:
[0010] A semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane is immersed in a monomer solution for hydrothermal reaction, and a nanoarray is grown in situ on the fiber surface and the inner wall of the inter-fiber pores. Finally, the membrane is washed and dried to obtain the composite nanofiber membrane.
[0011] The nanoarray is one or a combination of COFs, MOFs and TiO2;
[0012] III. Hot-pressing crystallization strengthening:
[0013] High-strength and superhydrophilic nanofiber membranes are obtained by hot-pressing composite nanofiber membranes at high temperature.
[0014] An application of a high-strength and superhydrophilic nanofiber membrane for oil-water separation.
[0015] The beneficial effects of this invention are:
[0016] This invention utilizes pre-dispersed crystalline nanoparticles such as COFs, MOFs, and TiO2 in semi-crystalline engineering plastics as growth seeds. A nanofiber membrane containing these crystalline growth seeds is then electrospinned. Subsequently, a hydrothermal reaction is used to grow the target crystals in situ onto the fiber surface and the inner walls of the inter-fiber pores, forming a nanoarray. The interaction between the crystalline regions of the semi-crystalline engineering plastic, the crystalline regions of the introduced crystalline nanoparticles, and the amorphous segments enhances the bonding stability at fiber overlap points. Subsequent hot-pressing crystallization further promotes the orientation of the semi-crystalline engineering plastic segments and the refinement of the crystalline regions, thereby improving the overall mechanical properties of the fiber membrane.
[0017] Taking Example 1 as an example, the high-strength and superhydrophilic nanofiber membrane prepared by the present invention has a tensile strength of 83.2 MPa; in the separation tests of water-in-octane emulsion and water-in-toluene emulsion, the aqueous phase permeation flux is 34300.7 L·m⁻¹, respectively. -2 ·h -1 ·bar -1 and 39342.5 L·m -2 ·h -1 ·bar -1 The separation efficiency for emulsified oil droplets was 99.9%. Furthermore, the prepared high-strength and superhydrophilic nanofiber membranes maintained their intact fiber morphology even after being immersed in strong acids, strong alkalis, and various organic solvents for 180 days. Attached Figure Description
[0018] Figure 1 The images show the microstructure of the high-strength and superhydrophilic nanofiber membrane prepared in Example 1 and the nanofiber membrane prepared in Comparative Example 1. a is a scanning electron microscope image of the nanofiber membrane without growth seeds in Comparative Example 1, b is a scanning electron microscope image of the nanofiber membrane with growth seeds added in Example 1, and c is a transmission electron microscope image of the nanofiber membrane with growth seeds added in Example 1.
[0019] Figure 2The microstructure of the high-strength and superhydrophilic nanofiber membrane prepared in Example 1 after immersion in different organic solvents and strong acid and strong alkali solutions for 180 days is shown. a is CH2Cl2, b is NMP, c is HCl solution (pH=1), and d is NaOH aqueous solution (pH=14).
[0020] Figure 3 Infrared spectra of the high-strength and superhydrophilic nanofiber membrane prepared in Example 1 and the nanofiber membrane prepared in Comparative Example 1. Detailed Implementation
[0021] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.
[0022] Specific Implementation Method 1: This implementation method describes a method for preparing high-strength and superhydrophilic nanofiber membranes via co-crystallization, which is carried out according to the following steps:
[0023] I. Preparation of nanofiber membranes containing crystal growth seeds:
[0024] ① At room temperature, semi-crystalline engineering plastic is mixed with an organic solvent to obtain a semi-crystalline engineering plastic solution;
[0025] ② The semi-crystalline engineering plastic solution is mixed with crystalline nanoparticles to obtain the casting solution;
[0026] ③ The casting solution is electrospun to obtain a semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane;
[0027] II. Preparation of composite nanofiber membranes:
[0028] A semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane is immersed in a monomer solution for hydrothermal reaction, and a nanoarray is grown in situ on the fiber surface and the inner wall of the inter-fiber pores. Finally, the membrane is washed and dried to obtain the composite nanofiber membrane.
[0029] The nanoarray is one or a combination of COFs, MOFs and TiO2;
[0030] III. Hot-pressing crystallization strengthening:
[0031] High-strength and superhydrophilic nanofiber membranes are obtained by hot-pressing composite nanofiber membranes at high temperature.
[0032] The beneficial effects of this embodiment are:
[0033] This embodiment uses pre-dispersed crystalline nanoparticles such as COFs, MOFs, and TiO2 as growth seeds in semi-crystalline engineering plastics. A nanofiber membrane containing these crystalline growth seeds is then produced via electrospinning. A hydrothermal reaction is then used to grow the target crystals in situ on the fiber surface and the inner walls of the inter-fiber pores, forming a nanoarray. The interaction between the crystalline regions of the semi-crystalline engineering plastic, the crystalline regions of the introduced crystalline nanoparticles, and the amorphous segments improves the bonding stability at fiber overlap points. Subsequent hot-pressing crystallization further promotes the orientation of the semi-crystalline engineering plastic segments and the perfection of the crystalline regions, thereby enhancing the overall mechanical properties of the fiber membrane.
[0034] Taking Example 1 as an example, the high-strength and superhydrophilic nanofiber membrane prepared in this embodiment has a tensile strength of 83.2 MPa; in the separation tests of water-in-octane emulsion and water-in-toluene emulsion, the aqueous phase permeation flux is 34300.7 L·m⁻¹, respectively. -2 ·h -1 ·bar -1 and 39342.5 L·m -2 ·h -1 ·bar -1 The separation efficiency for emulsified oil droplets was 99.9%. Furthermore, the prepared high-strength and superhydrophilic nanofiber membranes maintained their intact fiber morphology even after being immersed in strong acids, strong alkalis, and various organic solvents for 180 days.
[0035] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the semi-crystalline engineering plastic mentioned in step one ① is polyvinylidene fluoride, polyetheretherketone, polysulfone, or polyethersulfone, and the weight-average molecular weight of the semi-crystalline engineering plastic is 100,000 to 300,000; the organic solvent mentioned in step one ① is one or a combination of several of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; the mass percentage of the semi-crystalline engineering plastic solution mentioned in step one ① is 10% to 25%. Everything else is the same as in Specific Implementation Method One.
[0036] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the crystalline nanoparticles mentioned in step one ② are one or a combination of several of COF nanoparticles, MOF nanoparticles, and TiO2 nanoparticles; the crystalline nanoparticles mentioned in step one ② are dispersed crystalline nanoparticles, and the dispersion is specifically carried out according to the following steps: ultrasonic dispersion treatment for 0.5h to 3h under ultrasonic power of 200W~500W. Everything else is the same as in Specific Implementation Method One or Two.
[0037] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the COF nanoparticles are one or a combination of several of TpPa-COF, TpBD-COF, and TAPT-TFP-COF; the MOF nanoparticles are one or a combination of several of ZIF-8, ZIF-67, UiO-66, MIL-101(Cr), and HKUST-1; and the TiO2 nanoparticles are one or a combination of several of anatase TiO2, rutile TiO2, and TiO2(B). Everything else is the same as in Specific Implementation Methods One to Three.
[0038] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: the particle size of the crystalline nanoparticles mentioned in step one (②) is 20nm~500nm; the mass ratio of semi-crystalline engineering plastic to crystalline nanoparticles in the casting solution mentioned in step one (②) is (10~20):1. Everything else is the same as in Specific Implementation Methods One to Four.
[0039] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the electrospinning described in step one ③ is specifically performed under the following conditions: a positive voltage of 10kV~30kV, a negative voltage of 0kV~10kV, a needle inner diameter of 0.5mm~1.5mm, an injection rate of 0.0001mm / s~0.01mm / s, and a receiving roller speed of 100r / min~500r / min. Everything else is the same as in Specific Implementation Methods One to Five.
[0040] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: the monomer solution mentioned in step two is a monomer solution used for growing nanoarrays; when the monomer solution is a monomer solution used for growing TpPa-COF nanoarrays, the monomer solution is specifically prepared from p-phenylenediamine, trialdehyde phloroglucinol, and a solvent, and the total molar concentration of p-phenylenediamine and trialdehyde phloroglucinol in the monomer solution is 0.1 mol / L to 0.5 mol / L; the mass ratio of the semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane to the volume of the monomer solution in step two is 1 g:(50~200) mL; the hydrothermal reaction in step two is specifically carried out at a hydrothermal temperature of 80℃ to 150℃ for 18h to 30h. Everything else is the same as in Specific Implementation Methods One to Six.
[0041] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the high-temperature hot pressing treatment described in step three is specifically carried out at a temperature of 250℃~300℃ and a pressure of 1MPa~5MPa for 10min~60min. Everything else is the same as in Specific Implementation Methods One to Seven.
[0042] Specific Implementation Method Nine: This implementation method describes the application of a high-strength and superhydrophilic nanofiber membrane for oil-water separation.
[0043] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Nine in that the high-strength and superhydrophilic nanofiber membrane described herein achieves a separation efficiency of over 99.9% for oil-in-water emulsions. Everything else is the same as in Specific Implementation Method Nine.
[0044] The beneficial effects of the present invention are verified using the following embodiments:
[0045] Example 1:
[0046] A method for preparing high-strength and superhydrophilic nanofiber membranes by co-crystallization, comprising the following steps:
[0047] I. Preparation of nanofiber membranes containing crystal growth seeds:
[0048] ① At room temperature, semi-crystalline engineering plastic is mixed with an organic solvent to obtain a semi-crystalline engineering plastic solution;
[0049] The semi-crystalline engineering plastic is polyetheretherketone (PEEK), and the weight-average molecular weight of the semi-crystalline engineering plastic is 150,000.
[0050] The organic solvent is N,N-dimethylformamide; the semi-crystalline engineering plastic solution has a mass percentage of 15%.
[0051] ② Under the condition of stirring speed of 600 r / min, the semi-crystalline engineering plastic solution is mixed with crystalline nanoparticles, and then stirred for 6 hours under the condition of stirring speed of 600 r / min to obtain casting solution;
[0052] The crystalline nanoparticles are a combination of TpPa-COF particles and anatase TiO2 nanoparticles in a mass ratio of 1:1; the crystalline nanoparticles are dispersed crystalline nanoparticles, and the dispersion is carried out in the following steps: ultrasonic dispersion treatment for 1.5 hours under ultrasonic power of 300W, and after dispersion, particle size testing and microscopic morphology observation should confirm that no obvious agglomeration has occurred.
[0053] The TpPa-COF particles have a particle size of 50 nm; the anatase TiO2 nanoparticles have a particle size of 20 nm.
[0054] The mass ratio of semi-crystalline engineering plastic to crystalline nanoparticles in the casting solution is 15:1.
[0055] ③ Under the conditions of a positive voltage of 13kV, a negative voltage of 2kV, a needle inner diameter of 1.2mm, an injection rate of 0.001mm / s, and a receiving roller speed of 200r / min, the casting solution was electrospun to obtain a semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane.
[0056] II. Preparation of composite nanofiber membranes:
[0057] At a temperature of 120℃, a semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane was immersed in a monomer solution and hydrothermally reacted for 24 hours. TpPa-COF nanoarrays were grown in situ on the fiber surface and the inner wall of the inter-fiber pores. Finally, the membrane was washed with deionized water and ethanol and dried to obtain the composite nanofiber membrane.
[0058] The monomer solution is used for growing TpPa-COF, specifically prepared from p-phenylenediamine, trialdehyde phloroglucinol, and a mixed solvent, with a molar ratio of p-phenylenediamine to trialdehyde phloroglucinol of 1:1; the total molar concentration of p-phenylenediamine and trialdehyde phloroglucinol in the monomer solution is 0.1 mol / L; the mixed solvent is a mixture of N,N-dimethylamide and 1,4-dioxane in a volume ratio of 1:1.
[0059] III. Hot-pressing crystallization strengthening:
[0060] The composite nanofiber membrane was subjected to high-temperature hot pressing treatment for 30 minutes at a temperature of 275℃ and a pressure of 3MPa to obtain a high-strength and superhydrophilic nanofiber membrane.
[0061] The TpPa-COF particles mentioned in step 1② of this embodiment are commercially available products, purchased from Xianfeng Nanotechnology Co., Ltd.
[0062] Example 2: This example differs from Example 1 in that: the crystalline nanoparticles mentioned in step 1② are a combination of ZIF-8 particles and anatase TiO2 nanoparticles in a mass ratio of 1:1; the reaction monomer solution is a reaction monomer solution used for growing ZIF-8, specifically prepared from zinc nitrate hexahydrate, 2-methylimidazole, and methanol solvent, with a molar ratio of zinc nitrate hexahydrate to 2-methylimidazole of 1:4; the total molar concentration of zinc nitrate hexahydrate and 2-methylimidazole in the reaction monomer solution is 0.25 mol / L. Everything else is the same as in Example 1.
[0063] In this embodiment, the ZIF-8 particles and anatase TiO2 nanoparticles are commercially available products, purchased from Xianfeng Nanotechnology Co., Ltd.
[0064] Example 3: This example differs from Example 1 in that the semi-crystalline engineering plastic mentioned in step 1① is polyvinylidene fluoride (PVDF), and the weight-average molecular weight of the semi-crystalline engineering plastic is 200,000. Everything else is the same as in Example 1.
[0065] Example 4: This example differs from Example 1 in that the mass percentage of the semi-crystalline engineering plastic solution mentioned in step 1① is 12%. Everything else is the same as in Example 1.
[0066] Example 5: This example differs from Example 1 in that, in step two, the semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane is immersed in the reactant monomer solution and hydrothermally reacted for 24 hours at a temperature of 80°C. Everything else is the same as in Example 1.
[0067] Example 6: This example differs from Example 1 in that, in step three, the composite nanofiber membrane is subjected to high-temperature hot pressing treatment for 30 minutes at a temperature of 250°C and a pressure of 3 MPa. Everything else is the same as in Example 1.
[0068] Comparative Example 1: This comparative example differs from Example 1 in that the addition of the seed growth is omitted in step one; and the nanofiber membrane is obtained in step three. Everything else is the same as in Example 1.
[0069] Comparative Example 2: This comparative example is a commercial oil-water separator membrane, purchased from Veolia membrane, model MW4040F50.
[0070] The high-strength and superhydrophilic nanofiber membrane prepared in Example 1 was subjected to a water contact angle test: at room temperature, 5 μL of deionized water was added to the membrane surface and the wetting process was recorded using a contact angle measuring instrument. The water droplet was completely wetted by the membrane within 0.1 s, indicating that the membrane surface has superhydrophilic properties.
[0071] The nanofiber membranes of the examples and comparative examples were subjected to separation tests using water-in-octane emulsions and water-in-toluene emulsions. The emulsions were oil-in-water emulsions in which oil droplets were dispersed in a continuous aqueous phase. The average droplet size was determined statistically using dynamic light scattering or microscopic imaging. During the test, the volume of the aqueous phase permeating through the membrane was recorded and the aqueous phase permeation flux was calculated. Simultaneously, the oil content in the permeate was detected, and the membrane's retention efficiency for the dispersed oil droplets was calculated. Tensile strength was tested using the same thin film tensile testing method. Before the test, the sample width, effective clamping distance, and tensile rate were recorded. The results are shown in Table 1.
[0072] Table 1. Detection results of nanofiber membranes in the examples and comparative examples.
[0073]
[0074] Figure 1The images show the microstructure of the high-strength and superhydrophilic nanofiber membrane prepared in Example 1 and the nanofiber membrane prepared in Comparative Example 1. a is a scanning electron microscope (SEM) image of the nanofiber membrane in Comparative Example 1 without growth seeds, b is a SEM image of the nanofiber membrane in Example 1 with growth seeds, and c is a transmission electron microscope (TEM) image of the nanofiber membrane in Example 1 with growth seeds.
[0075] As shown in Table 1, the tensile strength of the high-strength and superhydrophilic nanofiber membrane prepared in Example 1 is 83.2 MPa; the aqueous phase permeation flux through the water-in-octane emulsion is 34300.7 L·m⁻¹. -2 ·h -1 ·bar -1 The separation efficiency was 99.9%; the aqueous phase permeation flux for the water-in-toluene emulsion was 39342.5 L·m⁻¹. -2 ·h -1 ·bar -1 The separation efficiency was 99.9%. Compared with Comparative Example 1, Example 1 showed an approximately 9.7-fold increase in aqueous phase permeation flux in the water-in-octane emulsion test, and a significant improvement in the retention efficiency of dispersed oil droplets.
[0076] The high-strength and superhydrophilic nanofiber membrane prepared in Example 1 was cut into standard samples and completely immersed in six organic solvents (chloroform, acetonitrile, acetone, NMP, ethyl acetate, and dichloromethane), as well as HCl solution (pH=1) and NaOH aqueous solution (pH=14). These samples were statically immersed for 180 days in sealed, light-proof glass bottles at 25°C. Before immersion, all membrane samples were thoroughly rinsed with deionized water and dried in an oven at 60°C to constant weight, and their initial morphology was recorded. After immersion, the membranes were removed and repeatedly rinsed with plenty of deionized water to remove residual solvents and acid / alkali solutes from the surface. They were then dried again at 60°C, and the integrity of the fiber microstructure was observed using SEM. The results show that the high-strength and superhydrophilic nanofiber membrane prepared in Example 1 maintained its intact fiber morphology after immersion in strong acids, strong alkalis, and various organic solvents for 180 days.
[0077] Figure 2 The microstructure of the high-strength and superhydrophilic nanofiber membrane prepared in Example 1 after immersion in different organic solvents and strong acid and alkali solutions for 180 days is shown in the figure. a is CH2Cl2, b is NMP, c is HCl solution (pH=1), and d is NaOH aqueous solution (pH=14). As can be seen from the figure, after immersion in the four extreme media for 180 days, the fibers did not break, collapse, or melt. The COF pine needle array on the surface was uniformly attached without large-scale peeling, which proves that the membrane can withstand strong polar organic solvents, strong acid and strong alkali extreme environments.
[0078] Figure 3The infrared spectra of the high-strength and superhydrophilic nanofiber membrane prepared in Example 1 and the nanofiber membrane prepared in Comparative Example 1 are shown. The results show that there are no Ar-OH and -C=CN- characteristic peaks of TpPa-COF on the surface without growth seeds, while the nanofiber membrane with added TpPa growth seeds shows Ar-OH and -C=CN- characteristic peaks, which confirms the importance of adding growth seeds for surface structure regulation.
Claims
1. A method for preparing high-strength and superhydrophilic nanofiber membranes via co-crystallization, characterized in that... It is done in the following steps: I. Preparation of nanofiber membranes containing crystal growth seeds: ① At room temperature, semi-crystalline engineering plastic is mixed with an organic solvent to obtain a semi-crystalline engineering plastic solution; ② The semi-crystalline engineering plastic solution is mixed with crystalline nanoparticles to obtain the casting solution; ③ The casting solution is electrospun to obtain a semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane; II. Preparation of composite nanofiber membranes: A semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane is immersed in a monomer solution for hydrothermal reaction, and a nanoarray is grown in situ on the fiber surface and the inner wall of the inter-fiber pores. Finally, the membrane is washed and dried to obtain the composite nanofiber membrane. The nanoarray is one or a combination of COFs, MOFs and TiO2; III. Hot-pressing crystallization strengthening: High-strength and superhydrophilic nanofiber membranes are obtained by hot-pressing composite nanofiber membranes at high temperature.
2. The method for preparing high-strength and superhydrophilic nanofiber membranes by co-crystallization according to claim 1, characterized in that... The semi-crystalline engineering plastic mentioned in step 1① is polyvinylidene fluoride, polyetheretherketone, polysulfone, or polyethersulfone, and the weight-average molecular weight of the semi-crystalline engineering plastic is 100,000 to 300,000; the organic solvent mentioned in step 1① is one or a combination of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; the mass percentage of the semi-crystalline engineering plastic solution mentioned in step 1① is 10% to 25%.
3. The method for preparing high-strength and superhydrophilic nanofiber membranes by co-crystallization according to claim 1, characterized in that... The crystalline nanoparticles mentioned in step 1② are one or a combination of several of COF nanoparticles, MOF nanoparticles and TiO2 nanoparticles; the crystalline nanoparticles mentioned in step 1② are dispersed crystalline nanoparticles, and the dispersion is carried out according to the following steps: ultrasonic dispersion treatment for 0.5h to 3h under ultrasonic power of 200W~500W.
4. The method for preparing high-strength and superhydrophilic nanofiber membranes by co-crystallization according to claim 3, characterized in that... The COF nanoparticles are one or a combination of several of TpPa-COF, TpBD-COF, and TAPT-TFP-COF; the MOF nanoparticles are one or a combination of several of ZIF-8, ZIF-67, UiO-66, MIL-101(Cr), and HKUST-1; the TiO2 nanoparticles are one or a combination of several of anatase TiO2, rutile TiO2, and TiO2(B).
5. The method for preparing high-strength and superhydrophilic nanofiber membranes by co-crystallization according to claim 1, characterized in that... The particle size of the crystalline nanoparticles mentioned in step 1② is 20nm~500nm; the mass ratio of semi-crystalline engineering plastic to crystalline nanoparticles in the casting solution mentioned in step 1② is (10~20):
1.
6. The method for preparing high-strength and superhydrophilic nanofiber membranes by co-crystallization according to claim 1, characterized in that... The electrospinning described in step 1③ specifically involves electrospinning under the following conditions: positive voltage of 10kV~30kV, negative voltage of 0kV~10kV, needle inner diameter of 0.5mm~1.5mm, injection rate of 0.0001mm / s~0.01mm / s, and receiving roller speed of 100r / min~500r / min.
7. The method for preparing high-strength and superhydrophilic nanofiber membranes by co-crystallization according to claim 1, characterized in that... The monomer solution mentioned in step two is a monomer solution used for growing nanoarrays; when the monomer solution is a monomer solution used for growing TpPa-COF nanoarrays, the monomer solution is specifically prepared by p-phenylenediamine, trialdehyde phloroglucinol and solvent, and the total molar concentration of p-phenylenediamine and trialdehyde phloroglucinol in the monomer solution is 0.1mol / L~0.5mol / L; the mass ratio of the semi-crystalline engineering plastic / nanoparticle composite nanofiber membrane to the volume of the monomer solution in step two is 1g:(50~200)mL; the hydrothermal reaction mentioned in step two is specifically carried out at a hydrothermal temperature of 80℃~150℃ for 18h~30h.
8. The method for preparing high-strength and superhydrophilic nanofiber membranes by co-crystallization according to claim 1, characterized in that... The high-temperature hot pressing treatment mentioned in step three is specifically carried out at a temperature of 250℃~300℃ and a pressure of 1MPa~5MPa for 10min~60min.
9. The application of the high-strength and superhydrophilic nanofiber membrane prepared according to claim 1, characterized in that... It is used for oil-water separation.
10. The application of a high-strength and superhydrophilic nanofiber membrane according to claim 9, characterized in that... The high-strength and superhydrophilic nanofiber membrane described above has a separation efficiency of over 99.9% for oil-in-water emulsions.