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

Abstract

The invention 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 steps that 1, a trisubstituted benzene derivative group and a first solvent are mixed and dissolved according to a certain proportion and then subjected to ultrasonic dispersion, and a clear solution is obtained; 2) adding a certain mass of acetic acid into the clear solution, freezing to below zero DEG C, and then performing vacuum freeze drying to obtain a dried product; (3) heating the dried product obtained in the step (2) to obtain a yellow product; washing and drying the yellow product, and collecting to obtain deep yellow powder; (4) dispersing the deep yellow powder obtained in the step (3) in a second solvent, and carrying out intermittent ultrasonic treatment to form a self-assembled dispersion liquid, and (5) collecting an upper suspension in the self-assembled dispersion liquid, and carrying out centrifugal concentration on the suspension to obtain the covalent organic framework material TPA-COF.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a covalent organic framework material TPA-COF, and belongs to the field of electrode material preparation and application. Background Art

[0002] Covalent organic framework materials are a type of porous material formed by organic molecules connected by covalent bonds. Their large specific surface area and excellent stability can provide sufficient ion adsorption sites. Therefore, covalent organic framework materials can be used in the fields of greenhouse gas capture, lithium-ion batteries and capacitive deionization. Among them, capacitive deionization technology uses the action of an external electric field to form a double layer, so that ions can migrate to the electrode surface for adsorption. Currently, capacitive deionization is mostly used to remove inorganic ions, heavy metal ions, microorganisms and some organic matter from water bodies due to its advantages such as low energy consumption and simple operation. It mainly involves brackish water treatment, low-salinity seawater desalination, industrial wastewater treatment and domestic wastewater purification.

[0003] At present, the most widely used electrode material in capacitive deionization technology is still porous carbon material, and its adsorption process is mainly based on the double-layer storage mechanism. Therefore, it still faces the problems of low adsorption capacity, limited adsorption rate and poor cycle stability. Covalent organic framework materials, as a new type of electrode material, have shown great application potential in capacitive deionization technology due to their high specific surface area and porosity. However, this type of material also exposes some problems in practical application, specifically including: easy dissociation in water and destruction of structure, thus affecting long-term use; the synthesis of materials involves a complex molecular assembly process, so the uniformity of the overall material structure cannot be guaranteed, and the structure of existing materials is not conducive to ion transport. In water treatment applications, it is difficult to restore the initial adsorption performance after adsorption saturation, and the regeneration performance is poor; therefore, it is necessary to develop a covalent organic framework material that can be well used in capacitive deionization technology. Summary of the invention

[0004] The present invention provides a preparation method and application of a covalent organic framework material TPA-COF, the purpose of which is to prepare a covalent organic framework material that can be used as an electrode active material in capacitive deionization technology.

[0005] The technical solution of the present invention is a method for preparing a covalent organic framework material TPA-COF, the method comprising: Step 1), the trisubstituted benzene derivative group and the first solvent are mixed and dissolved in a certain proportion, and then ultrasonically dispersed to obtain a clear solution; Step 2), adding a certain amount of acetic acid to the clear solution and freezing it to below zero degrees, followed by vacuum freeze drying to obtain a dry product; Step 3), heating the dried product obtained in step 2) to obtain a yellow product; washing the yellow product and drying it to obtain a dark yellow powder; Step 4), dispersing the dark yellow powder obtained in step 3) in a second solvent and subjecting it to intermittent ultrasonication to form a self-assembly dispersion; Step 5), collecting the upper suspension in the self-assembly dispersion, and concentrating the suspension by centrifugation to obtain the covalent organic framework material TPA-COF.

[0006] Furthermore, in step 1), the tri-substituted benzene derivative group is any two or more of the tri-substituted benzene derivatives such as 1,3,5-tris(4-aminophenyl)amine, 1,3,5-tris(4-nitrophenyl)amine, 1,3,5-tris(4-alkynylphenyl)amine, and 1,3,5-tris(4-carboxyphenyl)amine.

[0007] Furthermore, in the step 1), the first solvent is any one of water, methanol, ethanol, isopropanol, p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide, or a combination of several thereof; in the step 3), the washing solvent used to wash the yellow product is any one of water, methanol, ethanol, isopropanol, dichloromethane, anhydrous ethanol, anhydrous acetone, and anhydrous dichloromethane, or a combination of several thereof; in the step 4), the second solvent is any one of methanol, ethanol, isopropanol, N,N-dimethylformamide, and N,N-dimethylacetamide, or a combination of several thereof.

[0008] Furthermore, in the step 1), when the tri-substituted benzene derivative group is a combination of two tri-substituted benzene derivatives, the mass ratio of the two tri-substituted benzene derivatives in the tri-substituted benzene derivative group is 1:(0.1-10).

[0009] Furthermore, in the step 1), the mass volume ratio of the trisubstituted derivative group to the first solvent is 1:(0.05-20) in mg / mL; and in the step 2), the molar ratio of the added acetic acid to the trisubstituted benzene derivative group is 1:(0.1-100).

[0010] Furthermore, the vacuum freeze-drying time in step 2) is 24 hours to 96 hours; and in step 3), heating the dried product obtained in step 2) to obtain a yellow product is 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.

[0011] Furthermore, in the step 4), the intermittent ultrasound is set to be periodic ultrasound with a certain on-off cycle; the on-off cycle of the ultrasound is (5 to 60) seconds: (5 to 60) seconds, that is, ultrasound for 5 to 60 seconds, and then pause for 5 to 60 seconds is counted as one ultrasound cycle, and the ultrasound is repeated for several ultrasound cycles, and it is further preferred that a total of 5 to 10 ultrasound cycles are performed.

[0012] Furthermore, the prepared covalent organic framework material TPA-COF is suitable for electrode active materials.

[0013] A method for preparing a capacitive deionization electrode using the prepared covalent organic framework material TPA-COF comprises: Step (1), dissolving a covalent organic framework material TPA-COF, a conductive agent, and a binder in a solvent in a certain mass ratio, and stirring thoroughly to form a solution; the mass ratio of the covalent organic framework material TPA-COF, the conductive agent, and the binder is (7-9): (0.1-2): (0.5-2); Step (2), uniformly coating the solution formed in step (1) on graphite paper, and drying to obtain a TPA-COF capacitor deionization electrode.

[0014] 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; the drying temperature for drying the TPA-COF capacitor deionization electrode is 50°C to 150°C, and the drying time is 6 hours to 72 hours.

[0015] Beneficial effects of the present invention: 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, and its adjustable pore size structure and orderly pore arrangement are conducive to ion transport; 2) The preparation method of the covalent organic framework material TPA-COF of the present invention is flexible, simple to operate, and the product structure is adjustable; 3) The covalent organic framework material TPA-COF prepared by the present invention through reasonable design has a highly ordered layered two-dimensional framework structure, and forms an ordered pore structure and a large specific surface area as a whole, which significantly improves the adsorption capacity of substances such as nitrosamines in water; 4) The intermittent ultrasonic method selected in the preparation process of the present invention can avoid unnecessary stacking behavior between molecules, optimize the pore structure of the material, and enhance the structural stability of the material; 5) The covalent organic framework material TPA-COF prepared by the present invention is used to prepare an electrode for capacitive deionization, and the electrode prepared by the covalent organic framework material TPA-COF is applied to a capacitive deionization device, and the capacitive deionization device is applied to the enrichment treatment of a low-content nitrosamine solution, which can achieve rapid and high-throughput enrichment of nitrosamines; the electrode material prepared by the present invention can achieve rapid enrichment of trace nitrosamines in water by means of capacitive deionization, thereby improving the adsorption capacity and rate of the electrode and enhancing the enrichment effect, which is of great significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Attached Figure 1 This is a SEM image of the TPA-COF material in Example 1 of the present invention.

[0017] Attached Figure 2 This is a SEM image of the TPA-COF material in Example 1 of the present invention.

[0018] Attached Figure 3 This is a TEM image of the TPA-COF material in Example 1 of the present invention.

[0019] Attached Figure 4 This is a TEM image of the TPA-COF material in Example 1 of the present invention.

[0020] Attached Figure 5 : is the XRD pattern of the TPA-COF material in Example 1 of the present invention.

[0021] Attached Figure 6 It is a SEM picture of the activated carbon material in Comparative Example 1 of the present invention.

[0022] Attached Figure 7 It is a SEM picture of the activated carbon fiber material in Comparative Example 2 of the present invention.

[0023] Attached Figure 8 It is a concentration comparison chart of the materials after nitrosamine enrichment in Example 3, Comparative Example 1 and Comparative Example 2 of the present invention.

[0024] Attached Fig. 9 This is a graph showing the change in N-nitrosodiethylamine (NDEA) concentration in the N-nitrosodiethylamine (NDEA) solution in Example 3 before and after the adsorption and desorption enrichment treatment by the CDI device.

[0025] Attached Fig.10 It is the capacity retention rate of the enrichment performance in the stability test of five cycles in Example 4. DETAILED DESCRIPTION

[0026] A method for preparing a covalent organic framework material TPA-COF, the method comprising the following steps: Step 1), the trisubstituted benzene derivative group and the first solvent are mixed and dissolved in a certain proportion, and then ultrasonically dispersed to obtain a clear solution; Step 2), adding a certain amount of acetic acid to the clear solution and freezing it to below zero degrees, followed by vacuum freeze drying to obtain a dry product; Step 3), heating the dried product obtained in step 2) to obtain a yellow product; washing the yellow product and drying it to obtain a dark yellow powder; Step 4), dispersing the dark yellow powder obtained in step 3) in a second solvent and subjecting it to intermittent ultrasonication to form a self-assembly dispersion; Step 5), collecting the upper suspension in the self-assembly dispersion, and concentrating the suspension by centrifugation to obtain the covalent organic framework material TPA-COF.

[0027] The individual covalent organic framework material TPA-COF (Tris(4-(iminomethyl)phenyl)amine-based Covalent Organic Framework; tris(4-(iminomethyl)phenyl)amine covalent organic framework) prepared by the present invention is in the form of nanosheets and has a layered two-dimensional framework structure. Different nanosheet covalent organic framework materials TPA-COF form self-assembly aggregation during the preparation process to form a flower-shaped cluster distribution with a pore structure, and the distribution density of the nanosheet covalent organic framework material TPA-COF on the surrounding side walls of each flower-shaped cluster is greater than that of the middle part of the flower-shaped cluster, with clear edges and uniform distribution, and an obvious pore structure is formed inside the flower-shaped cluster, and different flower-shaped clusters also form obvious flow channels, and different nanosheet covalent organic framework materials TPA-COF also have a three-dimensional framework structure, and the pore structures are connected to form a pore network to form an efficient storage and transmission center.

[0028] Preferably, the trisubstituted benzene derivative group in step 1) is any two or more of the trisubstituted benzene derivatives such as 1,3,5-tris(4-aminophenyl)amine, 1,3,5-tris(4-nitrophenyl)amine, 1,3,5-tris(4-alkynylphenyl)amine, 1,3,5-tris(4-carboxyphenyl)amine, etc.; 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-alkynylphenyl)amine, or a combination of 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-carboxyphenyl)amine.

[0029] Preferably, in step 1), the first solvent is any one of water, methanol, ethanol, isopropanol, p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, or a combination of several thereof.

[0030] Preferably, when the tri-substituted benzene derivative group in step 1) is a combination of two tri-substituted benzene derivatives, the mass ratio of the two tri-substituted benzene derivatives in the tri-substituted benzene derivative group is preferably 1:(0.1-10); the mass ratio of the two tri-substituted benzene derivatives in the tri-substituted 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:( 0.1~10); when 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-alkynylphenyl)amine are combined, the mass ratio of 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-alkynylphenyl)amine is preferably 1:(0.1~10); when 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-carboxyphenyl)amine are combined, the mass ratio of 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-carboxyphenyl)amine is preferably 1:(0.1~10).

[0031] Preferably, in step 1), the mass volume ratio of the trisubstituted derivative group to the first solvent is 1:(0.05-20) in mg / mL, that is, every 1 mg of the trisubstituted derivative group is dissolved in 0.05 mL-20 mL of the first solvent.

[0032] Preferably, the molar ratio of the acetic acid added in step 2) to the tri-substituted benzene derivative group is preferably 1:(0.1-100).

[0033] Preferably, the vacuum freeze-drying time in step 2) is preferably 24 hours to 96 hours.

[0034] Preferably, in step 3), heating the dried product obtained in step 2) to obtain a yellow product is preferably heating the dried product obtained in step 2) at 60° C. to 150° C. for 24 to 96 hours to obtain a yellow product.

[0035] Preferably, the washing solvent used for washing the yellow product in step 3) is any one of water, methanol, ethanol, isopropanol, dichloromethane, anhydrous ethanol, anhydrous acetone, and anhydrous dichloromethane, or a combination of several of them.

[0036] Preferably, in step 4), the second solvent is any one of methanol, ethanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, or a combination of several of them.

[0037] In the step 4), the intermittent ultrasound is set to be periodic ultrasound with a certain on-off cycle; the on-off cycle (seconds) of the ultrasound is preferably (5-60): (5-60), that is, ultrasound for 5 seconds to 60 seconds, and then pause ultrasound for 5 seconds to 60 seconds is counted as one ultrasound cycle, and ultrasound is repeated for several ultrasound cycles, and it is further preferred that a total of 5 to 10 ultrasound cycles are performed.

[0038] The covalent organic framework material TPA-COF prepared by the present invention is suitable for electrode active materials.

[0039] A method for preparing a capacitor deionization electrode using the covalent organic framework material TPA-COF prepared by the present invention, the method comprising the following steps: Step (1), dissolving a covalent organic framework material TPA-COF, a conductive agent, and a binder in a solvent in a certain mass ratio, and stirring them thoroughly to form a solution; the mass ratio of the covalent organic framework material TPA-COF, the conductive agent, and the binder is preferably (7-9): (0.1-2): (0.5-2); preferably, the conductive agent is preferably 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; Step (2), uniformly coating the solution formed in step (1) on graphite paper, and drying at high temperature to obtain a TPA-COF capacitor deionization electrode; preferably, the drying temperature of the high temperature drying is 50°C to 150°C, and the drying time is 6 hours to 72 hours.

[0040] The present invention is further described below in conjunction with specific embodiments. Example 1

[0041] A method for preparing a covalent organic framework material TPA-COF, the method comprising the following steps: 1,3,5-tris(4-aminophenyl)amine and 1,3,5-tris(4-carboxyphenyl)amine are prepared into a trisubstituted benzene derivative group in a mass ratio of 1:1, and are dissolved in a mixed solvent of o-dichlorobenzene and ethanol in a mass volume ratio of 1:2 (mg / mL). After ultrasonic dispersion to obtain a clear solution, acetic acid is added in a molar ratio of acetic acid to the trisubstituted benzene derivative group of 1:1, and then freeze-dried to obtain a dry product. The dry product is heated and dried at 120°C for 72 hours. After drying, the product is centrifuged and washed several times with a solvent consisting of anhydrous ethanol, anhydrous acetone and anhydrous dichloromethane, and vacuum dried at 120°C for 72 hours to obtain a dark yellow powder. The dark yellow powder is dispersed in ethanol, and the on-off cycle is set to 5 seconds:5 seconds. After completing ten cycles of ultrasonic operation, the upper suspension is collected and centrifuged and concentrated to obtain TPA-COF nanosheets, that is, the covalent organic framework material TPA-COF is obtained.

[0042] The surface morphology of the covalent organic framework material TPA-COF (TPA-COF nanosheet) prepared in the embodiment was observed by scanning electron microscopy. Since the on-off cycle of the material during ultrasound was fixed, overheating was effectively avoided and the uniformity of the cavitation effect was improved, so that the looseness of the TPA-COF material increased, as shown in the attached electron microscope photo. Figure 1 , Attachment Figure 2 As shown in the figure, the prepared covalent organic framework material TPA-COF is a nano-scale layered stack with obvious cluster distribution. The pore structure is connected to form a pore network with clear edges and uniform distribution, forming an efficient storage and transmission center. Figure 3 , Attachment Figure 4 This is a TEM image of the TPA-COF nanosheet prepared in Example 1. The image clearly shows that the material has a layered structure of two-dimensional nanosheets with uniform size. The diameter of a single nanosheet is about 300 nm. Different nanosheet-shaped covalent organic framework materials TPA-COF form self-assembly aggregation during the preparation process to form a flower-shaped cluster distribution with a pore structure, and the distribution density of the nanosheet-shaped covalent organic framework material TPA-COF on the side walls of each flower-shaped cluster is greater than that of the middle part of the flower-shaped cluster, with clear edges and uniform distribution, and an obvious pore structure is formed inside the flower-shaped cluster; Figure 5This is the XRD spectrum of the TPA-COF nanosheets prepared in Example 1, wherein the diffraction peaks at 8.72°, 10.14° and 13.47° correspond to the (110), (200) and (210) crystal planes of the material, respectively, and the diffraction peak of the (001) crystal plane at 21.41° indicates that the spatial structure arrangement of the TPA-COF nanosheets becomes complex, and the two-dimensional nanosheets are stacked in an orderly manner to form a three-dimensional structure, which makes the pore structure of the material richer and the specific surface area of ​​the material increased, thereby increasing the adsorption sites, which is more conducive to the subsequent adsorption and desorption of nitrosamines. Example 2

[0043] The covalent organic framework material TPA-COF prepared in Example 1 is used to prepare a capacitive deionization electrode, which specifically includes the following steps: (1) The covalent organic framework material TPA-COF, conductive carbon black, and polyvinylidene fluoride were mixed and dissolved in N-methylpyrrolidone in a mass ratio of 8:1:1, and stirred until the solution was completely uniform; (2) The solution formed in step (1) is evenly coated on graphite paper, and dried at 90° C. for 24 hours to obtain a TPA-COF capacitor deionization electrode. Example 3

[0044] The TPA-COF capacitor deionization electrode obtained in Example 2 is used in a capacitor deionization device to enrich nitrosamines. The application includes: using the TPA-COF capacitor deionization electrode obtained in Example 2 as an anode and an activated carbon electrode as a cathode to assemble a capacitor deionization device, using a 0.2 mmol / L N-nitrosodiethylamine (NDEA) solution as an electrolyte solution, passing the electrolyte solution through the capacitor deionization device for capacitive deionization adsorption, and N-nitrosodiethylamine (NDEA) is adsorbed on the TPA-COF capacitor deionization electrode, and then short-circuiting the capacitor deionization device, and discharging another portion of the same concentration of 0.2 mmol / L N-nitrosodiethylamine (NDEA) solution. A mmol / L N-nitrosodiethylamine (NDEA) solution was passed through a capacitive deionization device, and the previously adsorbed N-nitrosodiethylamine (NDEA) was released and desorbed into the N-nitrosodiethylamine (NDEA) solution, thereby increasing the concentration of N-nitrosodiethylamine (NDEA) in the N-nitrosodiethylamine (NDEA) solution to complete the enrichment, wherein the ratio of the volume of the electrolyte solution used for enrichment to the volume of the electrolyte solution used for adsorption was 1:15; the solution obtained after the enrichment was used to detect the specific chemical shift signals generated by different chemical groups of NDEA (such as the hydrogen atoms on the ethyl group) using nuclear magnetic resonance spectroscopy, and the peak area was calculated after integrating the signal to determine the concentration of NDEA in the solution, thereby determining the degree of enrichment of NDEA.

[0045] As attached Fig. 9 As shown in the figure, the N-nitrosodiethylamine (NDEA) solution was treated for only 30 minutes before and after adsorption and desorption enrichment by the CDI device. Fig. 9 The concentration increased from 0.2 mmol / L to 1.6 mmol / L, and the enrichment factor reached 8 times. Figure 8 Compared with the electrode materials in Comparative Examples 1 and 2, the covalent organic framework material TPA-COF prepared by the present invention is 5 times higher than that of the activated carbon electrode and 5.5 times higher than that of the activated carbon fiber. Due to its ultra-thin nanosheet structure and the flower-shaped cluster distribution with a pore structure formed by self-assembly, it is beneficial to the adsorption and desorption of N-nitrosodiethylamine (NDEA), indicating that when nitrosamine enrichment is required, it can show better nitrosamine enrichment performance; for example, nitrosamines are mainly derived from drinking water disinfection, agricultural and industrial production, and food processing, and are usually present in the environment and food at extremely low concentrations. Although the concentration of nitrosamines and other pollutants in water bodies is usually very low, due to their extremely strong carcinogenicity, low-concentration pollution can also cause harm to environmental pollution and public health. In order to monitor the degree of water pollution, it is necessary to detect whether the water body contains nitrosamines and other pollutants. However, due to the relatively low content of nitrosamines and other pollutants in water bodies, it is difficult to directly and accurately detect whether the water body contains nitrosamines and other pollutants. Therefore, it is necessary to enrich the nitrosamines and other pollutants in the water body before testing, so as to achieve the detection, supervision and removal of nitrosamines; and the present invention can be used for the adsorption, desorption and enrichment of nitrosamines.

[0046] Comparative Example 1 This comparative example provides an application of enriching nitrosamines using capacitive deionization, which is different from Example 3 only in that the anode electrode material is replaced with activated carbon, and the other steps are the same as Example 3.

[0047] Comparative Example 2 This comparative example provides an application of enriching nitrosamines using capacitive deionization, which differs from Example 3 only in that the anode electrode material is replaced with activated carbon fiber, and the other steps are the same as Example 3. Example 4

[0048] This embodiment provides an application of using a TPA-COF capacitive deionization electrode in a capacitive deionization device to enrich nitrosamines, which is the same as the single-pass operation steps of Example 3, except that five consecutive adsorption and desorption enrichment cycles are performed to verify the cyclic stability of the capacitive deionization device during the nitrosamine enrichment process.

[0049] From the attached Fig.10It can be seen that the capacity retention rate of the enrichment performance in the five-cycle stability test is stable at more than 95%. The device shows excellent cycle stability, indicating that the capacitive deionization 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 and the first solvent are mixed and dissolved in a certain proportion, and then ultrasonically dispersed to obtain a clear solution; Step 2), adding a certain amount of acetic acid to the clear solution and freezing it to below zero degrees, followed by vacuum freeze drying to obtain a dry product; Step 3), heating the dried product obtained in step 2) to obtain a yellow product; The yellow product was washed and dried to obtain a dark yellow powder; Step 4), dispersing the dark yellow powder obtained in step 3) in a second solvent and subjecting it to intermittent ultrasonic treatment to form a self-assembly dispersion; Step 5), collecting the upper suspension in the self-assembly dispersion, and concentrating the suspension by centrifugation to obtain the covalent organic framework material TPA-COF.

2. The method for preparing a covalent organic framework material TPA-COF according to claim 1, characterized in that In step 1), the trisubstituted benzene derivative group is any two or more of 1,3,5-tris(4-aminophenyl)amine, 1,3,5-tris(4-nitrophenyl)amine, 1,3,5-tris(4-alkynylphenyl)amine, and 1,3,5-tris(4-carboxyphenyl)amine.

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

4. The method for preparing a covalent organic framework material TPA-COF according to claim 2, characterized in that When the tri-substituted benzene derivative group in step 1) is a combination of two tri-substituted benzene derivatives, the mass ratio of the two tri-substituted benzene derivatives in the tri-substituted benzene derivative group is 1:(0.1-10).

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

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

7. The method for preparing a covalent organic framework material TPA-COF according to claim 1, characterized in that In the step 4), the intermittent ultrasound is set to be 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 5-60 seconds and then pause for 5-60 seconds is counted as one ultrasound cycle, and the ultrasound is repeated for several ultrasound cycles.

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

9. A method for preparing a covalent organic framework material TPA-COF according to any one of claims 1 to 7, characterized in that The method for preparing a capacitive deionization electrode using the prepared covalent organic framework material TPA-COF comprises: Step (1), dissolving a covalent organic framework material TPA-COF, a conductive agent, and a binder in a solvent in a certain mass ratio, and stirring thoroughly to form a solution; the mass ratio of the covalent organic framework material TPA-COF, the conductive agent, and the binder is (7-9): (0.1-2): (0.5-2); Step (2), uniformly coating the solution formed in step (1) on graphite paper, and drying to obtain a TPA-COF capacitor deionization electrode.

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

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