A core-shell structure covalent organic framework / carbon nanotube fiber, a preparation method and application thereof

Abstract

The application provides a kind of core-shell structure covalent organic framework / carbon nanotube fiber, preparation method and application thereof, and relates to the field of functional materials and environmental pollution control technology.The fiber takes polysulfonamide as the mechanical support inner core, and the surface is in-situ grown with COFs functional layer rich in-OH and-COOH functional groups.The preparation method adopts the strategy of microfluidic spinning and in-situ interface growth coordination, first extrudes a precursor fiber with clear core-shell interface through microfluidic extrusion, and then in-situ synthesizes COFs layer on the surface of the fiber through solvothermal reaction.The method fundamentally solves the problem that traditional powder COFs are difficult to be macroscopically formed and recycled.The fiber has both continuous form and weavability, is easy to be processed into fabric, can efficiently and synchronously adsorb anion and cation pollutants in water by simply adjusting the environmental pH, and provides an innovative solution for developing intelligent and engineering application water treatment adsorption materials.

Description

Technical Field

[0001] This invention relates to the field of functional materials and environmental pollution control technology, specifically to a core-shell structured covalent organic framework / carbon nanotube fiber, its preparation method, and its applications. Background Technology

[0002] In the field of water pollution control, residual organic dyes (such as methylene blue) and heavy metal ions (such as hexavalent chromium Cr(VI)) in industrial wastewater pose a serious threat to the ecological environment and human health. Adsorption methods, due to their simplicity, high removal efficiency, and environmental friendliness, have become an important technical means for treating these pollutants. In recent years, covalent organic frameworks (COFs) have shown outstanding potential in adsorption separation due to their highly ordered pore structure, extremely large specific surface area, tunable organic functional groups, and good chemical stability, and are considered a promising new type of adsorption material. Carbon nanotubes (CNTs), with their extremely high specific surface area and unique hollow tubular structure, provide abundant adsorption sites and efficient mass transfer channels. Simultaneously, their surface is easily functionalized, enhancing their affinity for specific pollutants, thus showing great potential in adsorption fields such as wastewater treatment, gas separation, and environmental remediation.

[0003] However, despite the excellent adsorption performance of COFs, they still face significant challenges in practical engineering applications. Most reported COF materials are in micron or nanometer-scale powder form. While this form exposes more active sites, it has significant shortcomings in practical water treatment scenarios: powder materials are difficult to separate quickly and completely from treated water, easily leading to secondary pollution; recycling and regeneration processes are cumbersome and costly, limiting their reusability and economic feasibility; furthermore, powdered COFs cannot be directly packed or integrated into continuous flow treatment devices (such as fixed-bed adsorption columns, membrane separation modules, or textile-based filtration systems), limiting their large-scale, continuous application. This contradiction essentially stems from the mismatch between the superior microscale performance of COF materials and their poor macroscopic morphological engineering applicability.

[0004] To promote the practical application of COFs, existing technologies attempt to process or composite them into macroscopic structures. Common methods include electrospinning, solution blowing, 3D printing, and template-assisted loading to fix them onto polymer fibers or porous supports. However, these methods still have several common drawbacks: First, COFs are often unevenly distributed in the support and are prone to agglomeration, leading to a decrease in the utilization rate of effective adsorption sites. Second, the composite preparation process may damage the crystalline structure of COFs or block their pores, weakening their inherent high adsorption capacity. Third, the resulting composite materials often suffer from insufficient mechanical strength and poor flexibility, making it difficult to weave into fabrics or withstand the impact of actual water flow. Fourth, there is a lack of fine control over the internal microstructure of the fibers (such as core-shell structures), making it difficult to balance the mechanical support function of the support with the efficient surface adsorption function of the COFs. In addition, most existing macroscopically structured COFs materials have relatively simple functions and are difficult to efficiently remove pollutants with opposite charges (such as cationic methylene blue and anionic Cr(VI)) in the same system. Their adsorption mechanism often depends on the surface charge characteristics, and the simultaneous removal of pollutants with different charges requires precise design and control of the material surface properties.

[0005] Therefore, there is still a lack of COFs-based adsorbent materials in the current technology that can simultaneously meet the following requirements: maintain the high adsorption performance of COFs themselves while achieving the engineering applicability of their macroscopic morphology; possess good mechanical strength and structural stability, suitable for dynamic water treatment environments; and be able to achieve efficient and simultaneous removal of multiple types of pollutants (especially including dyes and heavy metal ions with different charge properties) under a wide range of conditions or in a single material system. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention discloses a core-shell covalent organic framework / carbon nanotube fiber and its preparation method, which possesses high adsorption capacity, excellent cycling stability, good mechanical properties, and dual functionality (simultaneous removal of anionic and cationic pollutants), in order to promote the large-scale application of COFs / CNT adsorbent materials in practical water treatment.

[0007] To achieve the above technical objectives, in a first aspect, the present invention proposes a core-shell structured covalent organic framework / carbon nanotube fiber, wherein the fiber is composed of a core and a COFs / CNT shell covering the core; the core is a high molecular weight aromatic polymer, and the COFs / CNT shell contains carbon nanotubes and a covalent organic framework formed by covalently connecting aldehyde monomers and amine monomers; The aromatic polymer is selected from any one of polysulfonamide, polyimide or polyaryletherketone; The aldehyde monomer is selected from any one of 2,4,6-tricarboxymethyl phloroglucinol, mesitylene benzoaldehyde, or terephthalaldehyde. The amine monomer is selected from any one of 2,5-diaminoterephthalic acid, p-phenylenediamine, or biphenylenediamine; The fibers have a continuous porous structure with a specific surface area of ​​8.55~13.26 m². 2 / g, with a pore size of 9~12 Å.

[0008] The core-shell structured covalent organic framework / carbon nanotube fiber of this invention consists of a core made of a high-molecular-weight aromatic polymer and an outer shell of COFs / CNTs, forming a macroscopic fiber with a well-defined interface and a continuous porous structure. This unique core-shell structure achieves synergy between macroscopic morphology and microscopic function: the high-molecular-weight aromatic polymer core provides mechanical support and fiber morphology, while the COFs and carbon nanotube shell, rich in hydroxyl and carboxyl functional groups, endow the fiber with high surface activity. The fiber itself exhibits excellent comprehensive performance, with a specific surface area of ​​8.55~13.26 m². 2 The fiber exhibits a pore size distribution concentrated in the 9–12 Å range, a thermal decomposition temperature exceeding 400℃, and structural stability within a pH range of 1–13. Regarding adsorption performance, the fiber material demonstrates an initial adsorption rate of 99.11–99.98% for 0.1 mmol / L methylene blue solution and 95.9–99.93% for 50 mg / L Cr(VI) solution at pH=2. After 10 adsorption-desorption cycles, its adsorption efficiency remains above 99.05% and 99.63%, respectively, exhibiting stability and reusability. This fiber combines high adsorption capacity, good flexibility, and direct weaving capabilities, providing a material basis for developing efficient, recyclable wastewater treatment adsorption materials and smart environmentally friendly textiles.

[0009] Secondly, the present invention also provides a method for preparing core-shell structured covalent organic framework / carbon nanotube fibers, the preparation method comprising Scheme 1 or Scheme 2; Scheme 1 includes the following steps: (1) Prepare high molecular aromatic polymer spinning solution and aldehyde monomer / CNT spinning solution respectively. Inject the two solutions into the core layer and shell layer channels of the microfluidic spinning device respectively. Under pressure drive, extrude them coaxially into the coagulation bath. After solidification and molding, stretch, wash and dry to obtain precursor fiber with core and shell structure. (2) The precursor fiber obtained in step (1) and the amine monomer are placed together in a solvent and subjected to a solvothermal polycondensation reaction under the catalysis of acetic acid, so that the aldehyde monomer in the precursor fiber shell reacts with the amine monomer, thereby forming a COFs / CNT shell in situ on the fiber surface. (3) The fiber product after the reaction in step (2) is washed and dried in sequence to obtain the core-shell structured covalent organic framework / carbon nanotube fiber; Scheme 2 includes the following steps: (1) Prepare high molecular aromatic polymer spinning solution and amine monomer / CNT spinning solution respectively. Inject the two solutions into the core layer and shell layer channels of the microfluidic spinning device respectively. Under pressure drive, extrude them coaxially into the coagulation bath. After solidification and molding, stretch, wash and dry to obtain precursor fiber with core and shell structure. (2) The precursor fiber obtained in step (1) and the aldehyde monomer are placed together in a solvent and subjected to a solvothermal polycondensation reaction catalyzed by acetic acid, so that the amine monomer in the precursor fiber shell reacts with the aldehyde monomer, thereby forming a COFs / CNT shell in situ on the fiber surface. (3) The fiber product after the reaction in step (2) is washed and dried in sequence to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0010] The method for preparing core-shell covalent organic framework / carbon nanotube fibers provided by this invention employs a synergistic strategy of constructing precursors through microfluidic spinning combined with in-situ growth of functional layers at the interface. Specifically, in Scheme 1, the core spinning solution of a high-molecular-weight aromatic polymer and the shell spinning solution of an aldehyde monomer / carbon nanotube are coaxially extruded through a microfluidic wet spinning device and then placed in a coagulation bath. Utilizing the dual diffusion effect of solvent and non-solvent, the polymer undergoes phase separation and solidification, forming an active precursor fiber with a clear core-shell interface. In this structure, the aromatic polymer is uniformly distributed in the fiber core, while the aldehyde monomer and carbon nanotubes are enriched in the outer shell, providing a structural basis for the subsequent in-situ growth of the covalent organic framework. Subsequently, using the precursor fiber as a template, it is placed in a solvent along with amine monomers and subjected to a solvothermal polycondensation reaction catalyzed by acetic acid. This causes the aldehyde monomers and amine monomers in the fiber shell to undergo a Schiff base condensation reaction, generating an OH-COOH functionalized covalent organic framework crystal layer with ketene-amine linkages (-C=CNC-) in situ. This forms a functionalized covalent organic framework / carbon nanotube shell on the fiber surface. Scheme 2 follows the same principle as Scheme 1, except that the loading positions and reaction order of the aldehyde and amine monomers are reversed: first, a precursor fiber containing amine monomers / carbon nanotubes is prepared by microfluidic spinning, and then it undergoes a solvothermal polycondensation reaction with the aldehyde monomers, similarly generating a functionalized covalent organic framework / carbon nanotube shell in situ on the fiber surface. This preparation method ingeniously combines the fiber forming process with the covalent organic framework synthesis process, which not only achieves a firm and uniform loading of the covalent organic framework on the macroscopic fiber carrier, but also completely preserves its porous structure and surface activity, fundamentally solving the common technical problem of covalent organic framework materials being difficult to macroscopically form and recycle.

[0011] In a further example of the present invention, in Scheme 1, the solvent in the polymeric aromatic spinning solution in step (1) is any one of N,N-dimethylacetamide, N,N-dimethylformamide, or N,N-dimethyl sulfoxide, and the mass concentration of the polymeric aromatic polymer is 9~14 wt%. In step (1), the solvent in the aldehyde monomer / CNT spinning solution is any one of N,N-dimethylacetamide, N,N-dimethylformamide or N,N-dimethyl sulfoxide, the mass concentration of the aldehyde monomer is 9~14 wt%, and the amount of CNT added is 5~10%. Alternatively, in Scheme 2, the solvent in the polymer spinning solution of the aromatic polymer in step (1) is any one of N,N-dimethylacetamide, N,N-dimethylformamide, or N,N-dimethyl sulfoxide, and the mass concentration of the aromatic polymer is 9~14 wt%. In step (1), the solvent in the amine monomer / CNT spinning solution is any one of N,N-dimethylacetamide, N,N-dimethylformamide or N,N-dimethyl sulfoxide, the mass concentration of the amine monomer is 9~14 wt%, and the amount of CNT added is 5~10%.

[0012] In a further example of the present invention, in scheme 1, the rate at which the aromatic polymer spinning solution is injected into the microfluidic spinning device in step (1) is 0.03 ml / min to 0.07 ml / min. The injection rate of the aldehyde monomer / CNT spinning solution into the microfluidic spinning device in step (1) is 0.04 ml / min to 0.08 ml / min; Alternatively, in Scheme 2, the injection rate of the aromatic polymer spinning solution into the microfluidic spinning device in step (1) is 0.03 ml / min to 0.07 ml / min. The injection rate of the amine monomer / CNT spinning solution into the microfluidic spinning device in step (1) is 0.04 ml / min to 0.08 ml / min.

[0013] In a further example of the present invention, in scheme 1 and / or scheme 2, the stretching speed in step (1) is 0.7~1.5 rpm.

[0014] In a further example of the present invention, in Scheme 1 and / or Scheme 2, the coagulation bath in step (1) is a mixture of water and N,N-dimethylacetamide, wherein the concentration of N,N-dimethylacetamide in the coagulation bath is 30~56wt%.

[0015] In a further example of the present invention, in scheme 1, the molar ratio of aldehyde monomer to amine monomer in the precursor fiber in step (2) is 1:(0.8~1), preferably 1:1; Alternatively, in Scheme 2, the molar ratio of amine monomers to aldehyde monomers in the precursor fiber in step (2) is (0.8~1):1, preferably 1:1.

[0016] In a further example of the present invention, in Scheme 1 and / or Scheme 2, the solvent in step (2) is selected from one or two of 1,4-dioxane and mesitylene. When the solvent is 1,4-dioxane and mesitylene, the volume ratio of 1,4-dioxane to mesitylene is (3~5):(4~6), preferably 5:6. And / or, the acetic acid in step (2) is a 6 mol / L acetic acid solution, and the amount of the 6 mol / L acetic acid solution is 4 to 8% of the total amount of the reaction system in step (2).

[0017] In a further example of the present invention, in Scheme 1 and / or Scheme 2, the temperature of the solvothermal polycondensation reaction in step (2) is 120°C to 180°C and the time is 72h to 96h; And / or, the washing solution used in step (3) is one or both of tetrahydrofuran or water; And / or, the drying temperature in step (3) is 120℃~140℃ and the time is 12~24h.

[0018] Thirdly, the present invention also provides an application of the core-shell structured covalent organic framework / carbon nanotube fiber prepared by the method described in the first aspect or the preparation method described in the second aspect, wherein the covalent organic framework / carbon nanotube fiber is woven into a fabric for the adsorption of pollutants in water.

[0019] The fiber of this invention successfully transforms high-performance adsorption fiber materials into directly usable engineered adsorption fabrics. By weaving the fiber into a fabric (preferably using a plain weave), not only is macroscopic integration and morphological reshaping of the material achieved, but the fabric is also synergistically endowed with excellent hydrophilicity and tunable surface charge. The fabric exhibits a water contact angle of 52° at the warp points and approximately 9° at the weft points due to rapid droplet spread, demonstrating superhydrophilic properties that greatly promote the contact between pollutants and active sites. Simultaneously, it possesses tunable surface charge characteristics over a wide pH range of 3-11, enabling efficient and simultaneous adsorption of anionic pollutants (such as Cr(VI)) and cationic pollutants (such as methylene blue dye) in water through simple adjustment of the fabric's ambient pH. This application ingeniously combines the intrinsic adsorption properties of the fiber, the macroscopic processing characteristics of the fabric, and the dynamic control of interfacial physicochemical properties, providing a new approach for developing intelligent, efficient, and easily deployable water treatment adsorption materials.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The core-shell structured covalent organic framework / carbon nanotube fiber of this invention has a core supported by a high-molecular-weight aromatic polymer, while the outer shell is composed of in-situ grown functionalized covalent organic frameworks and carbon nanotubes rich in hydroxyl (-OH) and carboxyl (-COOH) groups. This core-shell structured covalent organic framework / carbon nanotube fiber ingeniously solves the recycling problem of traditional powdered COFs, enabling the material to have a continuous fiber morphology, making it easy to weave into fabrics, wind, or fill, and achieving rapid solid-liquid separation.

[0021] The present invention discloses a method for preparing core-shell covalent organic framework / carbon nanotube fibers. This method employs a synergistic strategy of microfluidic spinning to construct a precursor and then growing it at the in-situ interface. This one-step process produces precursor fibers with a clear core-shell structure, which are then used as templates to grow functionally rich COF crystal layers in situ. This method combines the porosity and high activity of COFs with excellent macroscopic formability, structural stability, and processability, fundamentally solving the technical bottlenecks of macroscopic forming and recycling of COFs.

[0022] The core-shell structured covalent organic framework / carbon nanotube fiber of this invention can be engineered into fabrics that exhibit superhydrophilicity, facilitating the rapid diffusion of pollutants to adsorption sites. Combined with its continuous fiber morphology and macroscopic dimensions, the fabric of this invention can be directly integrated into filtration devices, flow reactors, or wearable water purification devices, solving the industry challenge of scaling up powdered COFs. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The image shows the cross-sectional morphology characterization results of PSA-COFs / CNT fibers using scanning electron microscopy (SEM) in Test Example 1 of the present invention; Figure 2 The image shows the surface morphology characterization results of PSA-COFs / CNT fibers using scanning electron microscopy (SEM) in Test Example 1 of the present invention; Figure 3 The X-ray diffraction pattern of Test Example 2 of the present invention is shown; Figure 4 The Fourier transform infrared (FT-IR) spectrum of Test Example 2 of the present invention is shown; Figure 5 The thermogravimetric analysis diagram of test example 3 of the present invention is shown; Figure 6 The surface charge environmental response characteristics of Test Example 3 of the present invention are shown in the figure. Figure 7 A two-dimensional fabric of PSA-COFs / CNT fibers is shown in Example 1 of the application of the present invention. Detailed Implementation

[0024] To facilitate understanding of the present invention, a more comprehensive description will be provided below, along with preferred embodiments. However, it should be understood that these embodiments are merely for more detailed explanation and should not be construed as limiting the invention in any way, i.e., not intended to limit the scope of protection of the invention.

[0025] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0026] It should be noted that the method for testing the adsorption rate of methylene blue dye in this embodiment of the invention is as follows: 10 mg of PSA-COFs / CNT fibers were uniformly dispersed in 10 ml of a 0.1 mmol / L aqueous solution of methylene blue dye at room temperature (25°C). The residual concentration of the solution was determined by UV-Vis spectrophotometry to calculate the adsorption rate. The formula for calculating the adsorption rate is as follows:

[0027] c0 is the initial concentration of the dye solution, and c is the concentration of the solution after adsorption equilibrium.

[0028] The adsorption rate test method for hexavalent chromium (Cr(VI)) is as follows: 10 mg of PSA-COFs / CNT fibers were uniformly dispersed in 10 ml of hexavalent chromium (Cr(VI)) (50 mg / L) solution at room temperature (25°C), and the residual concentration of the solution was determined by UV-Vis spectrophotometry to calculate the adsorption rate. The formula for calculating the adsorption rate is as follows.

[0029]

[0030] c0 is the initial concentration of the chromium ion solution, and c is the concentration of the solution after adsorption equilibrium.

[0031] Example 1 A method for preparing core-shell structured covalent organic framework / carbon nanotube fibers includes the following steps: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution containing 53 wt% DMAC in a mixed coagulation bath. Then, the fibers are stretched at a speed of 0.7 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber (PSA-COFs / CNT fiber).

[0032] The PSA-COFs / CNT fibers prepared using the method of this embodiment have a specific surface area of ​​13.26 m². 2 / g, pore size distribution concentrated in 9-12 Å; fracture strength of 11.13 MPa, and elongation at break of 2.40%.

[0033] Example 2

[0034] A method for preparing core-shell structured covalent organic framework / carbon nanotube fibers includes the following steps: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution and the shell spinning solution is a 13.5 wt% triphenylformaldehyde and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution containing 53 wt% DMAC and then stretched at a speed of 0.7 rpm in a stretching device. The collected fibers are then washed with deionized water at room temperature to remove uncured solvents and contaminants. The washed fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-triphenylformaldehyde / carbon nanotube precursor fibers with a core-shell structure. (2) The precursor fiber obtained in step (1) and p-phenylenediamine (the amount of which is equal to the molar amount of triphenylmethane in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and trimethylbenzene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, triphenylmethane in the precursor fiber shell undergoes a polycondensation reaction with p-phenylenediamine, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0035] The core-shell covalent organic framework / carbon nanotube fiber prepared using the method in this embodiment has a specific surface area of ​​10.11 m². 2 / g, pore size distribution concentrated in 10-12 Å; fracture strength of 10.1 MPa, and elongation at break of 1.7%.

[0036] Example 3

[0037] Based on the preparation method of core-shell covalent organic framework / carbon nanotube fibers in Example 1, the precursor fiber in this example is polysulfonamide-2,5-diaminoterephthalic acid / carbon nanotube, which is then subjected to a polycondensation reaction with 2,4,6-tricarboxymethyl phloroglucinol. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution and the shell spinning solution is a 13.5 wt% 2,5-diaminoterephthalic acid and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution mixed coagulation bath containing 53 wt% DMAC. Then, the fibers are stretched at a speed of 0.7 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. The washed fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,5-diaminoterephthalic acid / carbon nanotube precursor fibers with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,4,6-tricarboxymethyl phloroglucinol (the amount of which is the same as the molar amount of 2,5-diaminoterephthalic acid in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,5-diaminoterephthalic acid and 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergo a polycondensation reaction, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0038] The fiber prepared using the method of this embodiment has a specific surface area of ​​12.30 m². 2 / g, pore size distribution concentrated in 9-10 Å; fracture strength of 10.81 MPa, and elongation at break of 2%.

[0039] Example 4

[0040] The difference between this embodiment and Embodiment 1 is that the concentration of aldehyde monomers in the shell spinning solution was changed; all other conditions are the same as in Embodiment 1. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution and the shell spinning solution is a 9 wt% 2,4,6-tricarboxymethyl phloroglucinol and an 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution mixed coagulation bath containing 53 wt% DMAC. Then, the fibers are stretched at a speed of 0.7 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0041] The fiber prepared using the method of this embodiment has a specific surface area of ​​10.5 m². 2 / g, pore size distribution concentrated in 9-11 Å; fracture strength of 10.2 MPa, and elongation at break of 1.6%.

[0042] Example 5

[0043] The difference between this embodiment and Embodiment 1 is that the concentration of DMAC in the coagulation bath is changed; all other conditions are the same as in Embodiment 1. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at a flow rate of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution containing 30 wt% DMAC and then stretched at a speed of 0.7 rpm in a stretching device. The collected fibers are then washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0044] The fiber prepared using the method of this embodiment has a specific surface area of ​​8.55 m². 2 / g, pore size distribution concentrated in 9-10 Å; fracture strength of 10.3 MPa, and elongation at break of 1.9%.

[0045] Example 6

[0046] The difference between this embodiment and Embodiment 1 is that the injection rate of the shell spinning solution is changed; all other conditions are the same as in Embodiment 1. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.08 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution mixed coagulation bath containing 53 wt% DMAC. Then, the fibers are stretched at a speed of 0.7 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0047] The fiber prepared using the method of this embodiment has a specific surface area of ​​12.3 m². 2 / g, pore size distribution concentrated in 10-11 Å; fracture strength of 11.2 MPa, and elongation at break of 2%.

[0048] Example 7

[0049] The difference between this embodiment and Embodiment 1 is that the stretching speed of the stretching device is changed; all other conditions are the same as in Embodiment 1. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at a flow rate of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution containing 53 wt% DMAC in a mixed coagulation bath. Then, the fibers are stretched at a speed of 1.4 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0050] The fiber prepared using the method of this embodiment has a specific surface area of ​​13.11 m². 2 / g, pore size distribution concentrated in 9-11 Å; fracture strength of 10.8 MPa, and elongation at break of 1.5%.

[0051] Example 8

[0052] The difference between this embodiment and Embodiment 1 is that the injection rate of the core spinning solution is changed; all other conditions are the same as in Embodiment 1. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at a flow rate of 0.05 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution mixed coagulation bath containing 53 wt% DMAC. Then, the fibers are stretched at a speed of 0.7 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0053] The fiber prepared using the method of this embodiment has a specific surface area of ​​11.3 m². 2 / g, pore size distribution concentrated in 9-11 Å; fracture strength of 10.8 MPa, and elongation at break of 1.5%.

[0054] Example 9

[0055] The difference between this embodiment and Example 1 is that the temperature of the solvothermal polycondensation reaction in step (2) has been changed; other conditions are the same as in Example 1. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution containing 53 wt% DMAC in a mixed coagulation bath. Then, the fibers are stretched at a speed of 0.7 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 160°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0056] The fiber prepared using the method of this embodiment has a specific surface area of ​​10.3 m². 2 / g, pore size distribution concentrated in 9-11 Å; fracture strength of 10.1 MPa, and elongation at break of 1.2%.

[0057] Example 10

[0058] The difference between this embodiment and Example 1 is that the time of the solvothermal polycondensation reaction in step (2) has been changed; other conditions are the same as in Example 1. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution containing 53 wt% DMAC in a mixed coagulation bath. Then, the fibers are stretched at a speed of 0.7 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 84 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0059] The fiber prepared using the method of this embodiment has a specific surface area of ​​11.15 m². 2 / g, pore size distribution concentrated in 9-11 Å; fracture strength of 9.8 MPa, and elongation at break of 1.6%.

[0060] Example 11

[0061] The difference between this embodiment and Example 1 is that the ratio of the mixed solvent of 1,4-dioxane and mesitylene in step (2) has been changed, while other conditions are the same as in Example 1. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution containing 53 wt% DMAC in a mixed coagulation bath. Then, the fibers are stretched at a speed of 0.7 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a 1:1 volume ratio was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0062] The fiber prepared using the method of this embodiment has a specific surface area of ​​9.10 m². 2 / g, pore size distribution concentrated in 9-11 Å; fracture strength of 10.8 MPa, and elongation at break of 2.1%.

[0063] Example 12

[0064] The difference between this embodiment and Embodiment 1 is that the vacuum drying temperature in step (3) has been changed; other conditions are the same as in Embodiment 1. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide (DMAC) solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution containing 53 wt% DMAC in a mixed coagulation bath. Then, the fibers are stretched at a speed of 0.7 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 130°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0065] The fiber prepared using the method of this embodiment has a specific surface area of ​​10.10 m². 2 / g, pore size distribution concentrated in 9-12 Å; fracture strength of 11.1 MPa, and elongation at break of 2.2%.

[0066] Comparative Example 1

[0067] Based on the method for preparing core-shell covalent organic framework / carbon nanotube fibers in Example 1, this comparative example modifies the concentration of the core spinning solution during the preparation of precursor fibers. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is an 8 wt% polysulfonamide N,N-dimethylacetamide solution, and the shell spinning solution is a mixed solution of 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively, and after coaxial extrusion under pressure, enter a coagulation bath containing 53 wt% N,N-dimethylacetamide deionized water solution to solidify and form the fiber, and then stretch it at a speed of 0.7 rpm in a stretching device. Then wash the collected fiber with deionized water at room temperature to remove uncured solvent and contaminants. Spread the washed fiber flat to dry at room temperature (25~35℃), and turn it over every two hours to obtain the precursor fiber; (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0068] The fiber prepared using the method of this embodiment has a specific surface area of ​​5.44 m². 2 / g, pore size distribution concentrated in 10-11 Å; fracture strength of 6.1 MPa, and elongation at break of 0.3%.

[0069] Comparative Example 2

[0070] Based on the method for preparing core-shell covalent organic framework / carbon nanotube fibers according to Example 1, this comparative example adds aldehyde monomers and amine monomers simultaneously to the shell layer during the preparation of precursor fibers, rather than adding them stepwise. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% N,N-dimethylacetamide solution of polysulfonamide, and the shell spinning solution is a mixed solution of 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol, 13.5 wt% 2,5-diaminoterephthalic acid and 8 wt% N,N-dimethylacetamide of carbon nanotubes; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a mixed coagulation bath containing 53 wt% N,N-dimethylacetamide in deionized water. Then, the fibers are stretched at a speed of 0.7 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers are laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain precursor fibers. (2) The precursor fibers obtained in step (1) were placed in a pressure-resistant Pyrex tube. A mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was then added, along with 6M acetic acid as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface. (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0071] The fiber prepared using the method of this embodiment has a specific surface area of ​​6.22 m². 2 / g, pore size distribution concentrated in 12-14Å; fracture strength of 5 MPa, elongation at break of 0.5%.

[0072] Comparative Example 3

[0073] Based on the method for preparing core-shell covalent organic framework / carbon nanotube fibers in Example 1, this comparative example modifies the concentration of the shell spinning solution during the preparation of the precursor fibers. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% N,N-dimethylacetamide solution of polysulfonamide, and the shell spinning solution is a mixed solution of 8 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% N,N-dimethylacetamide of carbon nanotubes; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively, and after coaxial extrusion under pressure, enter a coagulation bath containing 53 wt% N,N-dimethylacetamide in a deionized aqueous solution to solidify and form the fiber, and then stretch it at a speed of 0.7 rpm in a stretching device. Then wash the collected fiber with deionized water at room temperature to remove uncured solvent and contaminants. Spread the washed fiber flat to dry at room temperature (25~35℃), and turn it over every two hours to obtain the precursor fiber; (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran (THF) and deionized water to remove unreacted monomers and byproducts. Then it is dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

[0074] The fiber prepared using the method of this embodiment has a specific surface area of ​​7.31 m². 2 / g, pore size distribution concentrated in 10-11 Å; fracture strength of 7 MPa, elongation at break of 0.7%.

[0075] Comparative Example 4

[0076] Based on the method for preparing core-shell covalent organic framework / carbon nanotube fibers according to Example 1, this comparative example changes the stretching speed of the stretching device during the preparation of precursor fibers. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively. After coaxial extrusion under pressure, the fibers are solidified in a deionized aqueous solution containing 53 wt% N,N-dimethylacetamide. Then, the fibers are stretched at a speed of 0.5 rpm in a stretching device. Finally, the collected fibers are washed with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 120°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran and deionized water to remove unreacted monomers and byproducts, and then dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber (PSA-COFs / CNT fiber).

[0077] The fiber prepared using the method of this embodiment has a specific surface area of ​​5.31 m². 2 / g, pore size distribution concentrated in 10-12 Å; fracture strength of 4 MPa, elongation at break of 0.2%.

[0078] Comparative Example 5

[0079] The method for preparing core-shell covalent organic framework / carbon nanotube fibers based on Example 1 differs in that the temperature of the solvothermal polycondensation reaction in step (2) is changed, while other conditions remain the same as in Example 1. The specific process is as follows: (1) Prepare core spinning solution and shell spinning solution respectively, wherein the core spinning solution is a 13.5 wt% polysulfonamide N,N-dimethylacetamide solution, and the shell spinning solution is a 13.5 wt% 2,4,6-tricarboxymethyl phloroglucinol and 8 wt% carbon nanotube N,N-dimethylacetamide solution; using a microfluidic injection pump, inject the core spinning solution and shell spinning solution into the corresponding channels of the microfluidic spinning device at flow rates of 0.06 ml / min and 0.05 ml / min respectively, and after coaxial extrusion under pressure, they enter a mixed coagulation bath containing 53 wt% DMAC deionized water solution to solidify and form, and then stretch them at a speed of 0.7 rpm in a stretching device, and then wash the collected fibers with deionized water at room temperature to remove uncured solvents and contaminants. After washing, the fibers were laid flat to dry at room temperature (25~35℃), and turned over every two hours to obtain polysulfonamide-2,4,6-tricarboxypyrogallol / carbon nanotube precursor fibers (PSA-TFP / CNT fibers) with a core-shell structure. (2) The precursor fiber obtained in step (1) and 2,5-diaminoterephthalic acid (the amount of which is equal to the molar amount of 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber) were placed in a pressure-resistant Pyrex tube. Then a mixed solvent consisting of 1,4-dioxane and mesitylene in a volume ratio of 5:6 was added, and 6M acetic acid was added as a catalyst. After sealing the tube, a solvothermal polycondensation reaction was carried out at a constant temperature of 90°C for 72 hours. During this process, 2,4,6-tricarboxymethyl phloroglucinol in the precursor fiber shell undergoes a polycondensation reaction with 2,5-diaminoterephthalic acid, thereby forming a COF shell in situ on the fiber surface; (3) The fiber product after the reaction in step (2) is washed thoroughly with tetrahydrofuran and deionized water to remove unreacted monomers and byproducts, and then dried under vacuum at 120°C for 12 hours to obtain the core-shell structured covalent organic framework / carbon nanotube fiber (PSA-COFs / CNT fiber).

[0080] The fiber prepared using the method of this embodiment has a specific surface area of ​​6.31 m². 2 / g, pore size distribution concentrated in 10-12 Å; fracture strength of 5.2 MPa, and elongation at break of 0.2%.

[0081] Test Example 1

[0082] Using the core-shell covalent organic framework / carbon nanotube fiber (PSA-COFs / CNT fiber) prepared in Example 1 as an example, its characterization was performed by scanning electron microscopy (SEM), such as... Figure 1 and Figure 2As shown, the synthesized COFs and CNTs are distributed solidly on the fiber shell layer, with the COFs growth thickness ranging from 5 to 15 μm. Furthermore, the fiber surface is uniformly covered with barbed COF crystals. Simultaneously, the COFs and CNTs are densely and uniformly arranged on the axial surface of the fiber.

[0083] Test Example 2

[0084] Using the core-shell covalent organic framework / carbon nanotube fiber (PSA-COFs / CNT fiber) prepared in Example 1 as the test object, X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy were performed sequentially to characterize its crystal structure and chemical bond composition in order to systematically resolve its crystal structure and chemical bond composition.

[0085] (1) Crystal structure analysis (XRD)

[0086] like Figure 3 As shown, the XRD pattern of PSA-COFs / CNT fibers exhibits significant diffraction peaks at 4.58° and 26.74°, corresponding to the (100) and (001) crystal planes, respectively, indicating that the material has a highly ordered crystal structure. According to the Bragg equation 2dsinθ=nλ (where d is the interplanar spacing, θ is the diffraction angle, n is the diffraction order, and λ is the X-ray wavelength), the interplanar spacing of this crystal plane is relatively large, which corresponds to the

[100] crystal plane unique to COFs materials, reflecting the periodic structure of the material in one dimension. The characteristic peak at 2θ=26.74° corresponds to the

[001] crystal plane spacing, which is relatively small. The ordered arrangement in the two crystal plane directions proves that the existence of these two characteristic peaks is a sign that the COFs material has an ordered crystal structure.

[0087] (2) Chemical bond structure analysis (FT-IR)

[0088] To further confirm the chemical nature of the bonds in the fiber, FT-IR testing was performed, and the results are as follows: Figure 4 As shown in the figure. At approximately 1550 cm... -1 The absorption peak at 1213 cm⁻¹ is attributed to the C=C vibration. -1 The absorption peaks appearing at this point are attributed to the CN vibration, and together they confirm the successful formation of the ketone-enamine linkage structure (-C=CNC-).

[0089] Test Example 3

[0090] Using the core-shell covalent organic framework / carbon nanotube fiber (PSA-COFs / CNT fiber) prepared in Example 1 as an example, its thermal stability and surface charge environmental response characteristics were systematically evaluated.

[0091] (1) Thermal stability analysis The thermal stability of the material was characterized by thermogravimetric analysis (TGA). The results are as follows: Figure 5 As shown, no significant mass loss was observed in PSA-COFs / CNT fibers below 400°C, indicating that the material has excellent structural stability in high-temperature environments.

[0092] (2) Surface charge environmental response characteristics The surface electrical properties of the material under different pH conditions were further quantified using Zeta potential measurements. Figure 6 As shown, the results indicate that the surface charge of PSA-COFs / CNT fibers can be effectively and stably regulated over a wide pH range from 3 to 11. This characteristic means that the material can adaptively capture pollutants with different electrical charges through electrostatic interactions, thereby adapting to complex actual water quality conditions.

[0093] Based on the above tests, the PSA-COFs / CNT fibers prepared in this invention possess both excellent thermal stability and intelligent surface charge response capabilities. These characteristics enable them to overcome the limitations of traditional adsorbent materials that are prone to deactivation under extreme or fluctuating pH environments, demonstrating their application potential in various industrial wastewater treatment scenarios.

[0094] Test Example 4

[0095] Using the core-shell covalent organic framework / carbon nanotube fibers prepared in Examples 1-6 and Comparative Examples 1-2 as examples, the adsorption rates of methylene blue dye and hexavalent chromium (Cr(VI)) were tested. The results are shown in Table 1.

[0096] Table 1. Test results of adsorption rates of methylene blue dye and hexavalent chromium (Cr(VI)).

[0097] As shown in Table 1, all examples exhibited excellent adsorption performance, with methylene blue adsorption rates ranging from 99.11% to 99.98% and hexavalent chromium (Cr(VI)) adsorption rates ranging from 95.90% to 99.93%. In particular, the core-shell structured covalent organic framework / carbon nanotube fiber (PSA-COFs / CNT fiber) prepared in Example 1 showed an initial adsorption rate as high as 99.98% when treated with 0.1 mmol / L methylene blue (MB) solution at room temperature; and an initial adsorption rate of 99.93% when treated with 50 mg / L hexavalent chromium (Cr(VI)) solution at pH=2.

[0098] Comparing Example 1 with Comparative Examples 1 and 3, it can be seen that the concentrations of polysulfonamide in the core spinning solution and 2,4,6-tricarboxymethylphloroglucinol (TFP) in the shell spinning solution significantly affect the fiber adsorption performance. Example 1, using a core spinning solution with 13.5 wt% polysulfonamide and a shell spinning solution with 13.5 wt% TFP, achieved a methylene blue adsorption rate of 99.98% and a hexavalent chromium adsorption rate of 99.93%. In Comparative Example 1, when the core polysulfonamide concentration was reduced to 8 wt%, the two adsorption rates decreased to 87.02% and 73.22%, respectively; in Comparative Example 3, when the shell TFP concentration was reduced to 8 wt%, the adsorption rates further decreased to 91.33% and 87.61%. This indicates that when the concentrations of the core and shell monomers are within the range defined by this invention, sufficient mechanical support and reaction sites can be provided for the fiber, ensuring the continuous and uniform growth of covalent organic frameworks (COFs) on the fiber surface, thereby achieving excellent adsorption capacity.

[0099] The rationality of the technical solution of the present invention was further verified by comparing the monomer addition order of Example 1 and Comparative Example 2. Example 1 adopted a stepwise method, that is, first fixing the aldehyde monomer (TFP) in the fiber shell, and then performing a solvothermal polycondensation reaction with the amino monomer (2,5-diaminoterephthalic acid, DABA), which resulted in the best adsorption performance. In contrast, Comparative Example 2 added TFP and DABA to the shell spinning solution at the same time (one-step blending method), which caused the two monomers to prematurely polycondense during the coagulation process, forming amorphous precipitates. This prevented the in-situ growth of an ordered COF shell on the fiber surface, and the adsorption rates of methylene blue and hexavalent chromium dropped to 90.08% and 79.33%, respectively. This comparison fully demonstrates that the stepwise method can effectively avoid premature monomer reaction and ensure the controllable growth of COFs on the fiber surface, which is a key technical feature for obtaining high adsorption performance.

[0100] Test Example 5

[0101] The core-shell covalent organic framework / carbon nanotube fiber prepared in Example 1 was used as the object for adsorption-desorption cycle testing.

[0102] Adsorption-desorption cycle tests were conducted. After 10 consecutive adsorption-desorption cycles, the average adsorption efficiency of the core-shell covalent organic framework / carbon nanotube fiber of this invention for MB remained at 99.26%, as shown in Table 2; the average adsorption rate for Cr(VI) remained at 99.82%, as shown in Table 3. These data indicate that the material structure is highly stable during repeated use, with no significant loss of active sites or pore collapse.

[0103] Therefore, the core-shell structured covalent organic framework / carbon nanotube fibers prepared by this invention have excellent cycling stability and reusability.

[0104] Table 2. Adsorption rate of MB by core-shell covalent organic framework / carbon nanotube fibers

[0105] Table 3. Adsorption rate of Cr(VI) by core-shell covalent organic framework / carbon nanotube fibers

[0106] Application Example 1

[0107] To enhance the practicality of PSA-COFs / CNT fibers, the one-dimensional PSA-COFs / CNT fibers prepared in Example 1 were further processed into a two-dimensional structured fabric. Specifically, a plain weave technique was used, where PSA-COFs / CNT fibers were interwoven as warp and weft yarns to prepare a two-dimensional PSA-COFs fiber fabric with dimensions of approximately 2 cm × 2 cm. The specific fabric pattern is shown below. Figure 7 As shown.

[0108] Test Example 6

[0109] The PSA-COFs / CNT fiber two-dimensional fabric prepared in accordance with Example 1 was subjected to a water contact angle (CA) test. Given that the plain weave fabric is made of warp and weft yarns interwoven, and its surface microstructure has directional differences, the warp and weft interweaving points on the fabric surface were selected as measurement points for this test.

[0110] The results show that the fabric exhibits excellent hydrophilicity. The water contact angle measured at the warp points was 52°, while the contact angle at the weft points was approximately 9° due to rapid droplet spread. These results indicate that the PSA-COFs / CNT fiber fabric possesses rapid wetting characteristics overall, and its wetting behavior exhibits controllable differences at different structural sites.

[0111] It should be noted that the above description is a further detailed explanation of the present invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the present invention to these descriptions. The specific parameters in this embodiment do not necessarily limit the technical solution, but merely illustrate one specific working condition. For those skilled in the art, various simple improvements and modifications can be made without departing from the concept of the present invention, and all such improvements and modifications should be considered to fall within the scope of protection of the present invention.

Claims

1. A core-shell structured covalent organic framework / carbon nanotube fiber, characterized in that, The fiber consists of a core and a COFs / CNT shell covering the core; the core is a high molecular weight aromatic polymer, and the COFs / CNT shell contains carbon nanotubes and a covalent organic framework formed by covalently connecting aldehyde monomers and amine monomers; The aromatic polymer is selected from any one of polysulfonamide, polyimide or polyaryletherketone; The aldehyde monomer is selected from any one of 2,4,6-tricarboxymethyl phloroglucinol, mesitylene benzoaldehyde, or terephthalaldehyde. The amine monomer is selected from any one of 2,5-diaminoterephthalic acid, p-phenylenediamine, or biphenylenediamine; The fibers have a continuous porous structure with a specific surface area of ​​8.55~13.26 m². 2 / g, with a pore size of 9~12 Å.

2. A method for preparing core-shell structured covalent organic framework / carbon nanotube fibers, characterized in that, The preparation method includes Scheme 1 or Scheme 2; Scheme 1 includes the following steps: (1) Prepare high molecular aromatic polymer spinning solution and aldehyde monomer / CNT spinning solution respectively. Inject the two solutions into the core layer and shell layer channels of the microfluidic spinning device respectively. Under pressure drive, extrude them coaxially into the coagulation bath. After solidification and molding, stretch, wash and dry to obtain precursor fiber with core and shell structure. (2) The precursor fiber obtained in step (1) and the amine monomer are placed together in a solvent and subjected to a solvothermal polycondensation reaction under the catalysis of acetic acid, so that the aldehyde monomer in the precursor fiber shell reacts with the amine monomer, thereby forming a COFs / CNT shell in situ on the fiber surface. (3) The fiber product after the reaction in step (2) is washed and dried in sequence to obtain the core-shell structured covalent organic framework / carbon nanotube fiber; Scheme 2 includes the following steps: (1) Prepare high molecular aromatic polymer spinning solution and amine monomer / CNT spinning solution respectively. Inject the two solutions into the core layer and shell layer channels of the microfluidic spinning device respectively. Under pressure drive, extrude them coaxially into the coagulation bath. After solidification and molding, stretch, wash and dry to obtain precursor fiber with core and shell structure. (2) The precursor fiber obtained in step (1) and the aldehyde monomer are placed together in a solvent and subjected to a solvothermal polycondensation reaction catalyzed by acetic acid, so that the amine monomer in the precursor fiber shell reacts with the aldehyde monomer, thereby forming a COFs / CNT shell in situ on the fiber surface. (3) The fiber product after the reaction in step (2) is washed and dried in sequence to obtain the core-shell structured covalent organic framework / carbon nanotube fiber.

3. The method for preparing core-shell structured covalent organic framework / carbon nanotube fibers according to claim 2, characterized in that, In Scheme 1, the solvent in the spinning solution of the aromatic polymer in step (1) is any one of N,N-dimethylacetamide, N,N-dimethylformamide, or N,N-dimethyl sulfoxide, and the mass concentration of the aromatic polymer is 9~14wt%. In step (1), the solvent in the aldehyde monomer / CNT spinning solution is any one of N,N-dimethylacetamide, N,N-dimethylformamide, or N,N-dimethyl sulfoxide, and the mass concentration of the aldehyde monomer is 9~14 wt%, and the mass concentration of CNT is 5~10 wt%. Alternatively, in Scheme 2, the solvent in the polymer spinning solution of the aromatic polymer in step (1) is any one of N,N-dimethylacetamide, N,N-dimethylformamide, or N,N-dimethyl sulfoxide, and the mass concentration of the aromatic polymer is 9~14wt%. In step (1), the solvent in the amine monomer / CNT spinning solution is any one of N,N-dimethylacetamide, N,N-dimethylformamide or N,N-dimethyl sulfoxide, the mass concentration of the amine monomer is 9~14 wt%, and the mass concentration of CNT is 5~10 wt%.

4. The method for preparing core-shell structured covalent organic framework / carbon nanotube fibers according to claim 2, characterized in that, In Scheme 1, the injection rate of the aromatic polymer spinning solution into the microfluidic spinning device in step (1) is 0.03 ml / min to 0.07 ml / min. The injection rate of the aldehyde monomer / CNT spinning solution into the microfluidic spinning device in step (1) is 0.04 ml / min to 0.08 ml / min; Alternatively, in Scheme 2, the injection rate of the aromatic polymer spinning solution into the microfluidic spinning device in step (1) is 0.03 ml / min to 0.07 ml / min. The injection rate of the amine monomer / CNT spinning solution into the microfluidic spinning device in step (1) is 0.04 ml / min to 0.08 ml / min.

5. The method for preparing core-shell structured covalent organic framework / carbon nanotube fibers according to claim 2, characterized in that, In Scheme 1 and / or Scheme 2, the rotational speed of stretching in step (1) is 0.7~1.5 rpm.

6. The method for preparing core-shell structured covalent organic framework / carbon nanotube fibers according to claim 2, characterized in that, In Scheme 1 and / or Scheme 2, the coagulation bath in step (1) is a mixture of water and N,N-dimethylacetamide, and the concentration of N,N-dimethylacetamide in the coagulation bath is 30~56wt%.

7. The method for preparing core-shell structured covalent organic framework / carbon nanotube fibers according to claim 2, characterized in that, In Scheme 1, the molar ratio of aldehyde monomers to amine monomers in the precursor fiber in step (2) is 1:(0.8~1). Alternatively, in Scheme 2, the molar ratio of amine monomers to aldehyde monomers in the precursor fiber in step (2) is (0.8~1):

1.

8. The method for preparing core-shell structured covalent organic framework / carbon nanotube fibers according to claim 2, characterized in that, In Scheme 1 and / or Scheme 2, the solvent in step (2) is selected from one or two of 1,4-dioxane and mesitylene. When the solvent is 1,4-dioxane and mesitylene, the volume ratio of 1,4-dioxane to mesitylene is (3~5):(4~6). And / or, the acetic acid in step (2) is a 6 mol / L acetic acid solution, and the amount of the 6 mol / L acetic acid solution is 4 to 8% of the total amount of the reaction system in step (2).

9. The method for preparing core-shell structured covalent organic framework / carbon nanotube fibers according to claim 2, characterized in that, In Scheme 1 and / or Scheme 2, the temperature of the solvothermal polycondensation reaction in step (2) is 120℃~180℃ and the time is 72h~96h; And / or, the washing solution used in step (3) is one or both of tetrahydrofuran or water; And / or, the drying temperature in step (3) is 120℃~140℃ and the time is 12~24h.

10. An application of a core-shell structured covalent organic framework / carbon nanotube fiber prepared using the method described in claim 1 or the method described in claims 2-9, characterized in that, The covalent organic framework / carbon nanotube fibers are woven into fabrics for the adsorption of pollutants in water.

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