Preparation method and application of a covalent organic framework material TPA-COF

Abstract

The application provides a preparation method and application of a covalent organic framework material TPA-COF. The preparation method of the covalent organic framework material TPA-COF comprises the following steps: in step 1, tri-substituted benzene derivatives are mixed with a first solvent at a certain proportion, dissolved and ultrasonically dispersed to obtain a clear solution; in step 2, a certain amount of acetic acid is added to the clear solution, and then the solution is frozen below zero degrees, and vacuum freeze-drying is performed to obtain a dry product; in step 3, the dry product obtained in step 2 is heated to obtain a yellow product; the yellow product is washed and dried to obtain a dark yellow powder; in step 4, the dark yellow powder obtained in step 3 is dispersed in a second solvent and intermittently ultrasonically dispersed to form a self-assembled dispersion liquid; and in step 5, the upper suspension in the self-assembled dispersion liquid is collected, and the suspension is centrifuged and concentrated to obtain the covalent organic framework material TPA-COF.

Description

Technical Field

[0001] This invention relates to a method for preparing and applying a covalent organic framework material TPA-COF, belonging to the field of electrode material preparation and application. Background Technology

[0002] Covalent organic frameworks (COFs), as a class of porous materials composed of organic molecules linked by covalent bonds, offer ample ion adsorption sites due to their large specific surface area and excellent stability. Therefore, COFs can be applied in fields such as greenhouse gas capture, lithium-ion batteries, and capacitive deionization. Capacitive deionization technology utilizes an external electric field to form an electric double layer, allowing ions to migrate to the electrode surface for adsorption. Currently, capacitive deionization is widely used to remove inorganic ions, heavy metal ions, microorganisms, and some organic matter from water bodies due to its low energy consumption and simple operation. Its applications primarily include brackish water treatment, low-salinity seawater desalination, industrial wastewater treatment, and domestic wastewater purification.

[0003] Currently, porous carbon materials remain the most widely used electrode materials in capacitive deionization technology. Their adsorption process is primarily based on the double-layer storage mechanism, thus still facing challenges such as low adsorption capacity, limited adsorption rate, and poor cycle stability. Covalent organic framework materials, as a novel type of electrode material, exhibit great application potential in capacitive deionization technology due to their high specific surface area and porosity. However, these materials also reveal some problems in practical applications, specifically: they are prone to dissociation in water, which destroys their structure and affects long-term use; their synthesis involves complex molecular assembly processes, making it difficult to guarantee the uniformity of the overall material structure; the existing structure is not conducive to ion transport; and after adsorption saturation in water treatment applications, it is difficult to restore the initial adsorption performance, resulting in poor regeneration performance. Therefore, it is necessary to develop a covalent organic framework material that can be well applied in capacitive deionization technology. Summary of the Invention

[0004] This invention proposes a method for preparing a covalent organic framework material TPA-COF and its application, with the aim of preparing a covalent organic framework material that can be used as an electrode active material in capacitive deionization technology.

[0005] The technical solution of this invention: a method for preparing a covalent organic framework material TPA-COF, the method comprising:

[0006] Step 1) The trisubstituted benzene derivative group is mixed and dissolved with the first solvent in a certain proportion and then ultrasonically dispersed to obtain a clear solution;

[0007] Step 2) After adding a certain mass of acetic acid to the clear solution, freeze it to below zero degrees Celsius, and then perform vacuum freeze-drying to obtain the dried product;

[0008] Step 3) Heat the dried product obtained in Step 2) to obtain a yellow product; wash the yellow product and dry it to collect a dark yellow powder;

[0009] Step 4) Disperse the dark yellow powder obtained in step 3) in a second solvent and perform intermittent sonication to form a self-assembled dispersion;

[0010] Step 5) Collect the upper suspension in the self-assembled dispersion, and centrifuge and concentrate the suspension to obtain the covalent organic framework material TPA-COF.

[0011] Further, in step 1), the trisubstituted benzene derivative group is any two or more combinations of trisubstituted benzene derivatives such as 1,3,5-tris(4-aminophenyl)amine, 1,3,5-tris(4-nitrophenyl)amine, 1,3,5-tris(4-ynylphenyl)amine, and 1,3,5-tris(4-carboxyphenyl)amine.

[0012] Further, in step 1), the first solvent is any one or a combination of several of water, methanol, ethanol, isopropanol, p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide; in step 3), the washing solvent used to wash the yellow product is any one or a combination of several of water, methanol, ethanol, isopropanol, dichloromethane, anhydrous ethanol, anhydrous acetone, and anhydrous dichloromethane; in step 4), the second solvent is any one or a combination of several of methanol, ethanol, isopropanol, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0013] Furthermore, when the trisubstituted benzene derivative group in step 1) is a combination of two trisubstituted benzene derivatives, the mass ratio of the two trisubstituted benzene derivatives in the trisubstituted benzene derivative group is 1:(0.1~10).

[0014] Further, in step 1), the mass-to-volume ratio of the trisubstituted derivative group to the first solvent is 1:(0.05-20) mg / mL; in step 2), the molar ratio of acetic acid to the trisubstituted benzene derivative group is 1:(0.1-100).

[0015] Further, in step 2), the vacuum freeze-drying time is 24 hours to 96 hours; in step 3), heating the dried product obtained in step 2) to obtain a yellow product involves heating the dried product obtained in step 2) at 60°C to 150°C for 24 hours to 96 hours to obtain a yellow product.

[0016] Furthermore, in step 4), the intermittent ultrasound is set to a periodic ultrasound with a certain on-off cycle; the on-off cycle of the ultrasound is (5-60) seconds: (5-60) seconds, that is, ultrasound for 5 seconds to 60 seconds, then pause ultrasound for 5 seconds to 60 seconds to count as one ultrasound cycle, and repeat ultrasound several times, more preferably a total of 5 to 10 ultrasound cycles.

[0017] Furthermore, the prepared covalent organic framework material TPA-COF is suitable for electrode active materials.

[0018] A method for preparing a capacitive deionization electrode using the prepared covalent organic framework material TPA-COF includes:

[0019] Step (1): Dissolve the covalent organic framework material TPA-COF, conductive agent, and binder in a solvent at a certain mass ratio, and stir thoroughly to form a solution; the mass ratio of the covalent organic framework material TPA-COF, conductive agent, and binder is (7-9):(0.1-2):(0.5-2).

[0020] Step (2): The solution formed in step (1) is uniformly coated onto graphite paper and dried to obtain the TPA-COF capacitor deionization electrode.

[0021] Furthermore, in the method for preparing a capacitor deionization electrode using the prepared covalent organic framework material TPA-COF, the conductive agent is any one or a combination of conductive carbon black, conductive graphite, graphene, and carbon nanotubes; the binder is any one or a combination of polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride (PVDF); the solvent is any one or a combination of ethanol, ethylene glycol, dichloromethane, dimethyl sulfoxide, and N-methylpyrrolidone; and the drying temperature for obtaining the TPA-COF capacitor deionization electrode is 50℃~150℃, and the drying time is 6 hours~72 hours.

[0022] The beneficial effects of this invention are:

[0023] 1) The covalent organic framework material TPA-COF (Tris(4-(iminomethyl)phenyl)amine-based Covalent Organic Framework) prepared by the method of the present invention is a two-dimensional high-efficiency electrode active material. Its tunable pore structure and ordered pore arrangement are conducive to ion transport.

[0024] 2) The preparation method of the covalent organic framework material TPA-COF of this invention is flexible, simple to operate, and the product structure is adjustable;

[0025] 3) The covalent organic framework material TPA-COF prepared by this invention has a highly ordered layered two-dimensional framework structure, and forms an ordered pore structure and a large specific surface area, which significantly improves the adsorption capacity for substances such as nitrosamines in water.

[0026] 4) The intermittent ultrasonic method selected in the preparation process of this invention can avoid unnecessary intermolecular stacking behavior, optimize the pore structure of the material, and enhance the structural stability of the material;

[0027] 5) Electrodes for capacitive deionization are prepared using the covalent organic framework material TPA-COF prepared in this invention. The electrodes prepared using this covalent organic framework material TPA-COF are applied to capacitive deionization devices. When these capacitive deionization devices are applied to the enrichment treatment of low-content nitrosamine solutions, rapid and high-throughput enrichment of nitrosamines can be achieved. The electrode material prepared in this invention can achieve rapid enrichment of trace amounts of nitrosamines in water by means of capacitive deionization, which improves the adsorption capacity and rate of the electrode and enhances the enrichment effect, which is of great significance. Attached Figure Description

[0028] Appendix Figure 1 This is a SEM image of the TPA-COF material in Embodiment 1 of the present invention.

[0029] Appendix Figure 2 This is a SEM image of the TPA-COF material in Embodiment 1 of the present invention.

[0030] Appendix Figure 3 This is a TEM image of the TPA-COF material in Embodiment 1 of the present invention.

[0031] Appendix Figure 4 This is a TEM image of the TPA-COF material in Embodiment 1 of the present invention.

[0032] Appendix Figure 5 This is the XRD pattern of the TPA-COF material in Embodiment 1 of the present invention.

[0033] Appendix Figure 6 This is a SEM image of the activated carbon material in Comparative Example 1 of this invention.

[0034] Appendix Figure 7 This is a SEM image of the activated carbon fiber material in Comparative Example 2 of this invention.

[0035] Appendix Figure 8 This is a comparison chart of the concentrations of nitrosamines after enrichment of the materials in Example 3, Comparative Example 1, and Comparative Example 2 of this invention.

[0036] Appendix Figure 9This is a graph showing the changes in the concentration of N-nitrosodiethylamine (NDEA) solution before and after adsorption and desorption enrichment treatment using a CDI device in Example 3.

[0037] Appendix Figure 10 It is the capacity retention rate of enrichment performance in the five-cycle stability test in Example 4. Detailed Implementation

[0038] A method for preparing a covalent organic framework material TPA-COF, the method comprising the following steps:

[0039] Step 1) The trisubstituted benzene derivative group is mixed and dissolved with the first solvent in a certain proportion and then ultrasonically dispersed to obtain a clear solution;

[0040] Step 2) After adding a certain mass of acetic acid to the clear solution, freeze it to below zero degrees Celsius, and then perform vacuum freeze-drying to obtain the dried product;

[0041] Step 3) Heat the dried product obtained in Step 2) to obtain a yellow product; wash the yellow product and dry it to collect a dark yellow powder;

[0042] Step 4) Disperse the dark yellow powder obtained in step 3) in a second solvent and perform intermittent sonication to form a self-assembled dispersion;

[0043] Step 5) Collect the upper suspension in the self-assembled dispersion, and centrifuge and concentrate the suspension to obtain the covalent organic framework material TPA-COF.

[0044] The covalent organic framework material TPA-COF (Tris(4-(iminomethyl)phenyl)amine-based Covalent Organic Framework) prepared in this invention is in the form of nanosheets with a layered two-dimensional framework structure. During the preparation process, different nanosheet-shaped TPA-COF materials form self-assembled agglomerates, resulting in flower-shaped clusters with porous structures. In each flower-shaped cluster, the nanosheet-shaped TPA-COF materials on the periphery are more densely distributed than those in the center, with clear edges and uniform distribution. Obvious porous structures are formed inside the flower-shaped clusters, and different flower-shaped clusters also form obvious flow channels. Different nanosheet-shaped TPA-COF materials also have a three-dimensional framework structure, and the interconnected porous structures form a pore network, creating efficient storage and transport centers.

[0045] Preferably, in step 1), the trisubstituted benzene derivative group is any two or more combinations of trisubstituted benzene derivatives such as 1,3,5-tris(4-aminophenyl)amine, 1,3,5-tris(4-nitrophenyl)amine, 1,3,5-tris(4-ynylphenyl)amine, and 1,3,5-tris(4-carboxyphenyl)amine; the trisubstituted benzene derivative in step 1) is further preferably a combination of 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-nitrophenyl)amine, or a combination of 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-ynylphenyl)amine, or a combination of 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-carboxyphenyl)amine.

[0046] Preferably, the first solvent in step 1) is any one or a combination of several of the following: water, methanol, ethanol, isopropanol, p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0047] Preferably, when the trisubstituted benzene derivative group in step 1) is a combination of two trisubstituted benzene derivatives, the mass ratio of the two trisubstituted benzene derivatives in the trisubstituted benzene derivative group is preferably 1:(0.1~10); the mass ratio of the two trisubstituted benzene derivatives in the trisubstituted benzene derivative group in step 1) is further preferably: when 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-nitrophenyl)amine are combined, the mass ratio of 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-nitrophenyl)amine is preferably 1:( The mass ratio of 1,3,5-tris(4-aminophenyl)amine to 1,3,5-tris(4-alkynylphenyl)amine in the combination of 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-alkynylphenyl)amine is preferably 1:(0.1 to 10);

[0048] Preferably, in step 1), the mass-to-volume ratio of the trisubstituted derivative group to the first solvent is 1:(0.05-20), that is, each 1 mg of the trisubstituted derivative group is dissolved in 0.05 mL to 20 mL of the first solvent.

[0049] Preferably, the molar ratio of acetic acid to the trisubstituted benzene derivative group added in step 2) is 1:(0.1-100).

[0050] Preferably, the vacuum freeze-drying time in step 2) is 24 hours to 96 hours.

[0051] Preferably, the step 3) involves heating the dried product obtained in step 2) to obtain a yellow product. More preferably, the dried product obtained in step 2) is heated at 60°C to 150°C for 24 to 96 hours to obtain the yellow product.

[0052] Preferably, the washing solvent used in step 3) to wash the yellow product is any one or a combination of several of the following: water, methanol, ethanol, isopropanol, dichloromethane, anhydrous ethanol, anhydrous acetone, and anhydrous dichloromethane.

[0053] Preferably, in step 4), the second solvent is any one or a combination of several of methanol, ethanol, isopropanol, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0054] In step 4), the intermittent ultrasound is set to a periodic ultrasound with a certain on-off cycle; the on-off cycle (seconds) of the ultrasound is preferably (5~60): (5~60) means that the ultrasound lasts for 5 seconds to 60 seconds, and then the ultrasound is paused for 5 seconds to 60 seconds, which is considered one ultrasound cycle. The ultrasound is repeated several times, and more preferably, a total of 5 to 10 ultrasound cycles are performed.

[0055] The covalent organic framework material TPA-COF prepared in this invention is suitable for electrode active materials.

[0056] A method for preparing a capacitive deionization electrode using the covalent organic framework material TPA-COF prepared according to the present invention, the method comprising the following steps:

[0057] Step (1): Dissolve the covalent organic framework material TPA-COF, conductive agent, and binder in a solvent at a certain mass ratio, and stir thoroughly to form a solution; the preferred mass ratio of the covalent organic framework material TPA-COF, conductive agent, and binder is (7-9):(0.1-2):(0.5-2); preferably, the conductive agent is any one or a combination of conductive carbon black, conductive graphite, graphene, and carbon nanotubes; the binder is any one or a combination of polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride (PVDF); preferably, the solvent is any one or a combination of ethanol, ethylene glycol, dichloromethane, dimethyl sulfoxide, and N-methylpyrrolidone.

[0058] Step (2): The solution formed in step (1) is uniformly coated onto graphite paper and dried at high temperature to obtain a TPA-COF capacitor deion electrode; preferably, the drying temperature at high temperature is 50℃~150℃ and the drying time is 6 hours~72 hours.

[0059] The present invention will be further described below with reference to specific embodiments. Example 1

[0060] A method for preparing a covalent organic framework material TPA-COF, the method comprising the following steps:

[0061] 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-carboxyphenyl)amine were combined in a mass ratio of 1:1 to form a trisubstituted benzene derivative group. The derivatives were dissolved in a mixed solvent of o-dichlorobenzene and ethanol at a mass-to-volume ratio of 1:2 (mg / mL). After ultrasonic dispersion to obtain a clear solution, acetic acid was added at a molar ratio of acetic acid to the trisubstituted benzene derivative group of 1:1, followed by freeze-drying to obtain a dried product. The dried product was then heated and dried at 120°C for 72 hours. After drying, the product was repeatedly centrifuged and washed with a solvent composed of anhydrous ethanol, anhydrous acetone, and anhydrous dichloromethane. It was then vacuum-dried at 120°C for 72 hours to obtain a deep yellow powder. This deep yellow powder was dispersed in ethanol, and after ten cycles of ultrasonic operation with a 5-second on / off cycle, the upper suspension was collected and centrifuged to concentrate the TPA-COF nanosheets, thus obtaining the covalent organic framework material TPA-COF.

[0062] The surface morphology of the covalent organic framework material TPA-COF (TPA-COF nanosheets) prepared in the examples was observed using scanning electron microscopy. By fixing the on / off cycle of the material during ultrasonication, overheating was effectively avoided and the uniformity of cavitation effect was improved, resulting in increased looseness of the TPA-COF material. See attached electron microscope images. Figure 1 Appendix Figure 2 As shown, the prepared covalent organic framework material TPA-COF is a nanoscale layered stack with a distinct cluster distribution. The interconnected pore structures form a porous network with clear edges and uniform distribution, creating efficient storage and transport centers. Figure 3 Appendix Figure 4 The image shows a TEM image of the TPA-COF nanosheets prepared in Example 1. The image clearly shows that the material has a two-dimensional nanosheet layered structure with uniform size; the diameter of a single nanosheet is approximately 300 nm. During the preparation process, the different nanosheet-shaped covalent organic framework materials TPA-COF self-assemble and aggregate, forming flower-shaped clusters with porous structures. The nanosheet-shaped TPA-COF on the periphery of each flower-shaped cluster is more densely distributed than the central part, with clear edges and uniform distribution. A distinct porous structure is formed within the flower-shaped clusters. Figure 5The XRD pattern of the TPA-COF nanosheets prepared in Example 1 shows that the diffraction peaks at 8.72°, 10.14° and 13.47° correspond to the (110), (200) and (210) crystal planes of the material, respectively. The diffraction peak at the (001) crystal plane at 21.41° indicates that the spatial structure of the TPA-COF nanosheets has become more complex. The orderly stacking of two-dimensional nanosheets forms a three-dimensional structure, which makes the pore structure of the material richer and increases the specific surface area of ​​the material. Therefore, the adsorption sites increase, which is more conducive to the subsequent adsorption and desorption of nitrosamines. Example 2

[0063] The preparation of a capacitive deionization electrode using the covalent organic framework material TPA-COF prepared in Example 1 includes the following steps:

[0064] (1) Mix the covalent organic framework material TPA-COF, conductive carbon black, and polyvinylidene fluoride in a mass ratio of 8:1:1 and dissolve them in N-methylpyrrolidone. Stir thoroughly until the solution is completely homogeneous.

[0065] (2) The solution formed in step (1) is uniformly coated on graphite paper and dried at 90°C for 24 hours to obtain TPA-COF capacitor deionization electrode. Example 3

[0066] The TPA-COF capacitive deionization electrode obtained in Example 2 was used for the enrichment of nitrosamines in a capacitive deionization device. This application included: assembling a capacitive deionization device using the TPA-COF electrode prepared in Example 2 as the anode and an activated carbon electrode as the cathode; using a 0.2 mmol / L N-nitrosodiethylamine (NDEA) solution as the electrolyte solution; passing the electrolyte solution through the capacitive deionization device for capacitive deionization adsorption; N-nitrosodiethylamine (NDEA) being adsorbed onto the TPA-COF capacitive deionization electrode; and then short-circuiting the capacitive deionization device to release another 0.2 mmol / L solution. A mmol / L N-nitrosodiethylamine (NDEA) solution is passed through a capacitive deionization device, where previously adsorbed N-nitrosodiethylamine (NDEA) is released and desorbed into the N-nitrosodiethylamine (NDEA) solution, increasing the concentration of N-nitrosodiethylamine (NDEA) in the solution and completing the enrichment. The ratio of the volume of electrolyte solution used for enrichment to the volume of electrolyte solution used for adsorption is 1:15. After enrichment, the resulting solution is analyzed using nuclear magnetic resonance spectroscopy to detect specific chemical shift signals generated by different chemical groups of NDEA (N-nitrosodiethylamine) (such as hydrogen atoms on the ethyl group). The peak area is calculated after integrating the signals to determine the concentration of NDEA in the solution, thereby determining the degree of NDEA enrichment.

[0067] As attached Figure 9 As shown, the N-nitrosodiethylamine (NDEA) solution, after adsorption and desorption enrichment treatment using a CDI device, requires only 30 minutes of processing time. Figure 9 The concentration increased from 0.2 mmol / L to 1.6 mmol / L, resulting in an enrichment factor of 8-fold, as shown in the attached figure. Figure 8 Compared with the electrode materials in Comparative Examples 1 and 2, the TPA-COF covalent organic framework material prepared in this invention exhibits superior performance, exceeding that of activated carbon electrodes by 5 times and activated carbon fibers by 5.5 times. Due to its ultrathin nanosheet structure and the self-assembled flower-shaped clusters with porous structures, the TPA-COF material facilitates the adsorption and desorption of N-nitrosodiethylamine (NDEA). This demonstrates its superior nitrosamine enrichment performance for applications requiring nitrosamine concentration. For example, nitrosamines mainly originate from drinking water disinfection, agricultural and industrial production, and food processing, and are typically present in extremely low concentrations in the environment and food. Although the concentration of pollutants such as nitrosamines in water bodies is usually very low, their strong carcinogenicity means that even low concentrations can harm the environment and public health. To monitor the degree of water pollution, it is necessary to detect whether the water contains pollutants such as nitrosamines. However, because the content of pollutants such as nitrosamines in water bodies is relatively low, it is difficult to accurately detect whether the water contains pollutants such as nitrosamines directly. Therefore, it is necessary to enrich the pollutants such as nitrosamines in the water body before detection, so as to realize the detection, monitoring and removal of nitrosamines. This invention can be used for the adsorption, desorption and enrichment of nitrosamines.

[0068] Comparative Example 1

[0069] This comparative example provides an application of capacitive deionization for the enrichment of nitrosamines. The only difference from Example 3 is that the anode electrode material is replaced with activated carbon, while the other steps are the same as in Example 3.

[0070] Comparative Example 2

[0071] This comparative example provides an application of nitrosamine enrichment using capacitive deionization. The only difference from Example 3 is that the anode electrode material is replaced with activated carbon fiber, while the other steps are the same as in Example 3. Example 4

[0072] This embodiment provides an application of TPA-COF capacitive deionization electrode in the enrichment of nitrosamines in a capacitive deionization device. The single-pass operation steps are the same as in Embodiment 3, except that five consecutive adsorption-desorption enrichment cycles are performed to verify the cyclic stability of the capacitive deionization device in the enrichment process of nitrosamines.

[0073] From the appendix Figure 10As can be seen, the capacity retention rate of the enrichment performance remained stable at over 95% after five cycles of stability testing. This device demonstrated excellent cycle stability, indicating that the capacitive deion electrode prepared using the covalent organic framework material TPA-COF has good regeneration performance and can meet the actual needs of nitrosamine enrichment.

Claims

1. A method for preparing a covalent organic framework material TPA-COF, characterized in that... include: Step 1) The trisubstituted benzene derivative group is mixed and dissolved with the first solvent in a certain proportion and then ultrasonically dispersed to obtain a clear solution; Step 2) After adding a certain mass of acetic acid to the clear solution, freeze it to below zero degrees Celsius, and then perform vacuum freeze-drying to obtain the dried product; Step 3) Heat the dried product obtained in Step 2) to obtain a yellow product; The yellow product was washed and dried, and a dark yellow powder was collected. Step 4) Disperse the dark yellow powder obtained in step 3) in a second solvent and perform intermittent sonication to form a self-assembled dispersion; Step 5) Collect the upper suspension in the self-assembled dispersion, and centrifuge and concentrate the suspension to obtain the covalent organic framework material TPA-COF; The trisubstituted benzene derivative group is a combination of 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-carboxyphenyl)amine.

2. The method for preparing a covalent organic framework material TPA-COF according to claim 1, characterized in that: In step 1), the first solvent is any one or a combination of several of the following: water, methanol, ethanol, isopropanol, p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide; in step 3), the washing solvent used to wash the yellow product is any one or a combination of several of the following: water, methanol, ethanol, isopropanol, dichloromethane, anhydrous ethanol, anhydrous acetone, and anhydrous dichloromethane; in step 4), the second solvent is any one or a combination of several of the following: methanol, ethanol, isopropanol, N,N-dimethylformamide, and N,N-dimethylacetamide.

3. The method for preparing a covalent organic framework material TPA-COF according to claim 1, characterized in that: The mass ratio of 1,3,5-tris(4-aminophenyl)amine to 1,3,5-tris(4-carboxyphenyl)amine in the trisubstituted benzene derivative group is 1:(0.1-10).

4. The method for preparing a covalent organic framework material TPA-COF according to claim 1, characterized in that: In step 1), the mass-to-volume ratio of the trisubstituted derivative group to the first solvent is 1:(0.05-20) mg / mL; in step 2), the molar ratio of acetic acid to the trisubstituted benzene derivative group is 1:(0.1-100).

5. The method for preparing a covalent organic framework material TPA-COF according to claim 1, characterized in that: In step 2), the vacuum freeze-drying time is 24 to 96 hours; in step 3), the dried product obtained in step 2) is heated to obtain a yellow product by heating the dried product obtained in step 2) at 60 ℃ to 150 ℃ for 24 to 96 hours to obtain a yellow product.

6. The method for preparing a covalent organic framework material TPA-COF according to claim 1, characterized in that: In step 4), the intermittent ultrasound is set to a periodic ultrasound with a certain on-off cycle; the on-off cycle of the ultrasound is (5~60) seconds: (5~60) seconds, that is, ultrasound for 5 seconds to 60 seconds, and then pause ultrasound for 5 seconds to 60 seconds to count as one ultrasound cycle, and repeat ultrasound several times.

7. The method for preparing a covalent organic framework material TPA-COF according to any one of claims 1-6, characterized in that: The prepared covalent organic framework material TPA-COF is suitable for electrode active materials.

8. The method for preparing a covalent organic framework material TPA-COF according to any one of claims 1-6, characterized in that: Methods for preparing capacitive deion electrodes using the prepared covalent organic framework material TPA-COF include: Step (1): Dissolve the covalent organic framework material TPA-COF, conductive agent, and binder in a solvent at a certain mass ratio, and stir thoroughly to form a solution; the mass ratio of the covalent organic framework material TPA-COF, conductive agent, and binder is (7-9):(0.1-2):(0.5-2). Step (2): The solution formed in step (1) is uniformly coated onto graphite paper and dried to obtain the TPA-COF capacitor deionization electrode.

9. The method for preparing a covalent organic framework material TPA-COF according to claim 8, characterized in that: In the method for preparing a capacitive deionization electrode using the prepared covalent organic framework material TPA-COF, the conductive agent is any one or a combination of conductive carbon black, conductive graphite, graphene, and carbon nanotubes; the binder is any one or a combination of polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride (PVDF); the solvent is any one or a combination of ethanol, ethylene glycol, dichloromethane, dimethyl sulfoxide, and N-methylpyrrolidone; and the drying temperature for obtaining the TPA-COF capacitive deionization electrode is 50℃~150℃, and the drying time is 6 hours~72 hours.

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