Viologen-based COFs (covalent organic frameworks) material and series plant growth device thereof for photocatalytic degradation of medical animal husbandry wastewater

Abstract

The invention discloses a viologen-based covalent organic framework material as well as a synthesis method and application thereof, through introduction of an electron donor type unit, a viologen structure is expanded, the stability of viologen free radicals is greatly enhanced, and meanwhile, the cycle performance of molecules is improved; the viologen-based covalent organic framework material obtained by adopting the viologen structure has the advantages of good thermal stability and cycling stability, reversible redox peaks and the like, and can be used as a catalyst for photocatalytic degradation of tetracycline antibiotic drugs; a series plant growth device for photocatalytic degradation of medical animal husbandry wastewater, which is built with a circulating pump, a metal net and the like, can be directly used for a device for changing wastewater into fertilizer water for agricultural irrigation, and is remarkable in degradation efficiency, high in cycling stability and capable of promoting plant root development.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental protection of photocatalytic materials, and specifically relates to the preparation and application of a type of viologen-based covalent organic framework material and a photocatalytic degradation of medical and animal husbandry wastewater in series with a plant growth device constructed therefrom. Background Art

[0002] Antibiotics are widely used in medicine and animal husbandry due to their effectiveness in treating bacterial infections. However, the production and abuse of antibiotics have led to the discharge of a large amount of antibiotic wastewater into the environment. Although the concentration of antibiotic residues in water systems is very low, it has the potential to cause extremely negative environmental impacts, such as antibiotic resistance in bacteria, damage to the ecosystem, and possible risks to human health. Several efficient and economical technologies have been developed to remove antibiotics from wastewater, including adsorption, microbial degradation, electrolysis, photocatalysis, and membrane separation. Among them, photocatalysis has attracted widespread attention due to its advantages such as environmental protection, economy, and high efficiency. However, the performance of photocatalysis depends largely on the photocatalyst used, so it is crucial to design a low-cost and efficient photocatalytic material. Organic photovoltaic materials have attracted widespread attention among many photocatalytic materials due to their abundance, low cost, and environmental protection. Conjugated radical cations have a wide range of applications in catalysis, energy storage, electrochromic display, and other fields due to their special properties; in addition, conjugated radical cations are also widely used in photocatalytic water treatment because the free radicals they produce can effectively degrade pollutants.

[0003] Covalent organic frameworks (COFs) are crystalline organic materials characterized by pre-designed polygonal networks with highly ordered pores. When the symmetry and planarity of each monomer are fixed, the resulting COFs can evolve into two-dimensional (2D) periodic frameworks that are further coaxially stacked via overlapping π interactions. As a result, it endows COFs with outstanding light absorption and strong conductivity. Most of the COFs reported so far are semiconductor materials with a band gap of 1.5-3.0 eV. Due to their covalent nature, these materials are strong and stable in air and various solvents, and only begin to degrade at high temperatures, so their photoelectric conversion in photocatalytic applications is unique. Among them, COFs materials that are insoluble in most solvents have attracted much attention: (i) insoluble materials can be easily purified by simple washing, while soluble materials require more complex purification techniques; (ii) insoluble materials can be easily separated from suspensions, which greatly facilitates recycling without causing significant loss of materials, improves cost-effectiveness, and minimizes waste; (iii) convenient separation simplifies the regeneration and reuse of materials. These properties make COFs materials that are insoluble in most solvents particularly important in fields such as catalysis and pollutant removal. They have been successfully used in catalysis, removal of pollutants from water and organic solvents, biomedical applications, and sensing.

[0004] Viologen analoges RV 2+ ) is an organic free radical compound that easily generates cationic free radicals after gaining electrons. It has a wide range of applications in optoelectronics. 2 + ), due to its radical cation (SeV + ) has excellent properties and can be used as a photosensitizer and electron transfer agent in photocatalysis. However, SeV obtained by existing preparation methods + It is unstable and easily dimerizes through intermolecular N coupling, thus limiting the electron transfer process; in addition, photocatalysis requires the selective transfer of electrons from the viologen cation to the metal catalytic center, while inhibiting pathways such as charge recombination. Competition between these pathways will also affect SeV 2+ Role in optoelectronic applications. There are few reports on the use of main group element viologen as free radicals to degrade pollutants, especially antibiotic pollutants. Existing photocatalytic water treatment devices only stay at the sewage treatment step and do not make full use of the beneficial elements in the treated water.

[0005] Therefore, SeV obtained by the existing preparation method + It is unstable, which limits its electron transfer process and thus affects its application in photocatalysis. The development of new organic photocatalytic degradation materials, especially selenium-containing violacein derivatives, to improve their photocatalytic performance and the design of a new photocatalytic degradation of medical and livestock wastewater in series with plant growth device are crucial to fully realizing the economic and agricultural benefits of the treated wastewater. Summary of the invention

[0006] SeV obtained by existing preparation methods + The present invention is unstable, thus limiting its electron transfer process and thus affecting its application in photocatalysis. The first object of the present invention is to provide a class of viologen-based covalent organic framework materials. The second object of the present invention is to provide a method for synthesizing viologen-based covalent organic framework materials. The third object of the present invention is to provide a device for photocatalytic degradation of medical and animal husbandry wastewater using viologen-based covalent organic framework materials.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a type of viologen-based covalent organic framework material, the structural unit of which is as follows:

[0009]

[0010] In the formula, R1 is Any one of the following, R2 is Any one of .

[0011] Furthermore, the viologen-based covalent organic framework material has a structural unit as follows:

[0012]

[0013] The viologen-based covalent organic framework material synthesis steps include: dispersing monomer I and monomer II in a mixed solvent, reacting at 110-130° C. for 24-48 hours to obtain a suspension; cooling the suspension to room temperature, washing, drying, and grinding to obtain the viologen-based covalent organic framework material;

[0014] Wherein, the monomer I is selected from any one of compounds 1 to 3

[0015]

[0016] Monomer II is selected from any one of compounds 4 to 5

[0017]

[0018] The preparation method of compound 5 in the monomer II is as follows: compound 6, compound 7 and copper acetate are dissolved in N, N-dimethylformamide (DMF), the resulting mixture is heated to 90-110° C. and stirred for 24-48 hours, cooled to room temperature, dichloromethane is added for precipitation, vacuum filtration is performed for separation, and washing is performed to obtain compound 4. The specific reaction is as follows:

[0019]

[0020] The molar ratio of the monomer I to the monomer II is 1:1 to 1:1.5.

[0021] The molar ratio of compound 6, compound 7 and copper acetate is 20:2:1.

[0022] A device for photocatalytic degradation of medical animal husbandry wastewater prepared from viologen-based covalent organic framework material comprises a power part, a catalytic part and a recycling part. The power part and the catalytic part are connected, and the wastewater treated by the catalytic part directly flows into the tank of the recycling part through a pipeline; the power part is composed of a peristaltic pump, and the photocatalytic part is composed of a metal mesh loaded with a cylindrical viologen-based covalent organic framework material and loaded into a high borosilicate glass hollow tube; the recycling part is composed of a hydroponic pool.

[0023] The application of the above-mentioned viologen-based covalent organic framework material in photocatalytic degradation of antibiotics.

[0024] The application of the device for photocatalytic degradation of medical and animal husbandry wastewater using the viologen-based covalent organic framework material in wastewater treatment.

[0025] The above-mentioned viologen-based covalent organic framework material is used in animal husbandry and wastewater treatment.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The method for synthesizing viologen-based covalent organic framework materials provided by the present invention expands the viologen structure by introducing an electron donor unit, realizes the direct arylation of viologen molecules for the first time, improves their free radical stability and electron transfer rate, and stabilizes the molecular structure, thereby solving the technical problem that the selenium-containing viologen obtained by the existing preparation method is unstable and limits its electron transfer, thereby affecting its application in photocatalysis; the covalent organic framework material is prepared by a one-pot method, the solvent used is low-cost, the method is simple, the yield is high, and it can be synthesized in large quantities at a fast synthesis rate.

[0028] (2) The viologen-based covalent organic framework material provided by the present invention has extremely poor solubility in organic solvents. Under the excitation of visible light, it generates photogenerated electrons and photogenerated holes. Both the photogenerated holes and the photogenerated electrons interact with antibiotics, and have strong photocatalytic activity and good cyclic stability. It is used as a catalytic unit of a photocatalytic degradation of medical and animal husbandry wastewater in series with a plant growth device. The treated wastewater is rich in nitrogen nutrients and can be used as a fertilizer to promote plant growth. Therefore, the viologen-based covalent organic framework material provided by the present invention can be used in the field of removing pollutants from water and organic solvents, and is particularly suitable for water treatment and agricultural applications. It is of great significance for the development of such viologen-based covalent organic framework materials in wastewater treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It shows a practical application scene picture of the photocatalytic degradation of medical and animal husbandry wastewater and the plant growth device in series provided by the present invention.

[0030] Figure 2 Shown is a metal mesh loaded with the viologen-based covalent organic framework material provided by the present invention.

[0031] Figure 3 Shown is the XRD diffraction pattern and calculated comparison diagram of the viologen-based covalent organic framework material provided by the present invention;

[0032] Figure 4 Shown is a transmission electron microscopy image of the viologen-based covalent organic framework material provided by the present invention;

[0033] Figure 5 Shown is a scanning electron microscope image of the viologen-based covalent organic framework material provided by the present invention;

[0034] Figure 6 The solid-state NMR image of the viologen-based covalent organic framework material provided by the present invention is shown;

[0035] Figure 7 Shown is a thermogravimetric graph of the viologen-based covalent organic framework material provided by the present invention;

[0036] Figure 8 Shown is the XPS graph of the viologen-based covalent organic framework material provided by the present invention;

[0037] Fig. 9 Shown is the electrochemical spectrum of the viologen-based covalent organic framework material provided by the present invention;

[0038] Fig.10 Shown is a solid-state EPR spectroelectrochemical spectrum of the viologen-based covalent organic framework material provided by the present invention;

[0039] Fig.11 Shown are performance test graphs of the viologen-based covalent organic framework material provided by the present invention under different conditions;

[0040] Fig.12 Shown is a catalytic cycle test diagram of the viologen-based covalent organic framework material provided by the present invention. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0042] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0043] Example 1

[0044] The viologen-based covalent organic framework material provided in this embodiment is obtained by coupling reaction of compound 3 and compound 5. The specific synthesis method is as follows:

[0045] 8 mg (0.025 mmol) of compound 3 and 17.6 mg (0.02 mmol) of compound 5 were dispersed in 2.5 mL of a mixed solvent of triethylamine: toluene = 1:1.5, and allowed to react at 120°C for 48 h to obtain a suspension; after the suspension was cooled to room temperature, it was washed with organic solvents acetonitrile, ether, and dichloromethane in sequence, dried, and ground to obtain a viologen-based covalent organic framework material, the structural unit of which is shown below:

[0046]

[0047] The synthesis method of the above-mentioned compound 5 is as follows: compound 6 (1300 mg, 2.2 mmol), compound 7 (52 mg, 0.22 mmol) and copper acetate (6.0 mg, 0.03 mmol) are dissolved in dry DMF (10 mL); the resulting mixture is heated to 100° C. and stirred for 36 h. After cooling to room temperature, the mixture is dropped into 50 mL of dichloromethane; the formed precipitate is separated by vacuum filtration and then thoroughly washed with dichloromethane and ether; after vacuum filtration, compound 4 is obtained as a yellow solid with a yield of 74%.

[0048] The chemical reaction formula is:

[0049]

[0050] Example 2

[0051] The viologen-based covalent organic framework material provided in this embodiment is obtained by coupling reaction of compound 3 and compound 4. The specific synthesis method is as follows:

[0052] 8.0 mg (0.025 mmol) of compound 3 and 17.6 mg (0.03 mmol) of compound 4 were dispersed in 2.5 mL of a mixed solvent of triethylamine: toluene = 1:1.5, and allowed to stand for reaction at 120°C for 48 h to obtain a suspension; after the suspension was cooled to room temperature, it was washed with organic solvents acetonitrile, ether, and dichloromethane in sequence, dried, and ground to obtain a viologen-based covalent organic framework material, the structural unit of which is shown below:

[0053]

[0054] The synthesis method of the above-mentioned compound 4 is as follows: compound 8 (1440 mg, 2.6 mmol), compound 9 (40 mg, 0.26 mmol) and copper acetate (6.0 mg, 0.03 mmol) are dissolved in dry DMF (10 mL); the resulting mixture is heated to 100° C. and stirred for 36 h. After cooling to room temperature, the mixture is dropped into 50 mL of dichloromethane; the formed precipitate is separated by vacuum filtration and then thoroughly washed with dichloromethane and ether; after vacuum filtration, compound 4 is obtained as a yellow solid with a yield of 87%.

[0055] The chemical reaction formula is:

[0056]

[0057] Example 3

[0058] The viologen-based covalent organic framework material provided in this embodiment is obtained by coupling reaction of compound 1 and compound 5. The specific synthesis method is as follows:

[0059] 7.9 mg (0.025 mmol) of compound 1 and 17.6 mg (0.02 mmol) of compound 5 were dispersed in 2.5 mL of a mixed solvent of triethylamine: toluene = 1:1.5, and allowed to react at 120°C for 48 h to obtain a suspension; after the suspension was cooled to room temperature, it was washed with organic solvents acetonitrile, ether, and dichloromethane in sequence, dried, and ground to obtain a viologen-based covalent organic framework material, the structural unit of which is shown below:

[0060]

[0061] Example 4

[0062] The viologen-based covalent organic framework material provided in this embodiment is obtained by coupling reaction of compound 2 and compound 5. The specific synthesis method is as follows:

[0063] 9.5 mg (0.025 mmol) of compound 2 and 17.6 mg (0.02 mmol) of compound 5 were dispersed in 2.5 mL of a mixed solvent of triethylamine: toluene = 1:1.5, and allowed to stand at 120°C for 48 h to obtain a suspension; after the suspension was cooled to room temperature, it was washed with organic solvents acetonitrile, ether, and dichloromethane in sequence, dried, and ground to obtain a viologen-based covalent organic framework material, the structural unit of which is shown below:

[0064]

[0065] Example 5

[0066] Application of the Viologen-Based Covalent Organic Framework Material Provided in Example 1

[0067] This example is based on Example 1-2. The viologen-based covalent organic framework material prepared by the coupling reaction is used in a medical animal husbandry wastewater treatment device. The device is shown in the attached Figure 1 As shown, it can be assembled and prepared by the following steps:

[0068] Step 1: Preparation of core catalytic material monomer;

[0069] The photocatalytic functional material for photocatalytic degradation of medical animal husbandry wastewater in series with plant growth device is prepared by the synthesis method disclosed in this patent, and a class of viologen-based covalent organic framework materials. The viologen-based covalent organic framework material has a hexagonal porous structure. Preparation of compound monomers: Disperse compound 8, compound 9 and copper acetate in dry N,N-dimethylformamide in a reaction tube. Heat the resulting mixture to 100°C and stir for 36 hours. After cooling to room temperature, drop the mixture into 50mL of dichloromethane. The formed precipitate is separated by vacuum filtration and then thoroughly washed with dichloromethane and ether. After vacuum filtration, compound 5 is a yellow solid.

[0070] Step 2: Preparation and loading of core catalytic covalent organic framework materials;

[0071] (1) Pretreatment of metal mesh: Place the metal mesh in a 500 mL beaker and use ultrapure water and anhydrous ethanol to ultrasonically clean it for 30 minutes in turn to remove the oil film on the metal surface; Place the cleaned metal mesh in a vacuum oven and dry it for 1 hour; Use 800 mesh and 400 mesh corundum sandpaper to grind it until the surface is rough and matte; Then place the metal mesh in a 500 mL beaker again and use ultrapure water and anhydrous ethanol to ultrasonically clean it for 30 minutes in turn to remove the debris on the metal surface, and then dry it to complete the metal pretreatment.

[0072] (2) Preparation and loading of covalent organic framework materials;

[0073] Add different monomer combinations to a specific mixed solvent in a pressure-resistant reaction bottle, ultrasonically disperse for 30 minutes, then add the treated metal mesh to the bottle, slowly heat to 120°C, and react for 48 hours without stirring to obtain a suspension. After the reaction solution is cooled to room temperature, take out the metal mesh, the color of the metal mesh changes significantly, and part of the covalent organic framework material is loaded on the metal mesh. Rinse with acetonitrile, ether, and dichloromethane three times in sequence, and then dry to obtain a metal mesh loaded with a covalent organic framework material. For details, see the attached Figure 2 shown.

[0074] Step 3: Assembly of the core catalytic unit;

[0075] A tubular mold is used to shape the metal mesh loaded with the covalent organic framework material into a hollow cylinder, and the cylindrical metal mesh is placed into a hollow borosilicate glass tube. The tubular mold is pulled out, and the treated metal mesh and the borosilicate glass are assembled together to form a catalytic core unit.

[0076] Step 4: Assembling a photocatalytic degradation of medical and animal husbandry wastewater in series with a plant growth device;

[0077] The photocatalytic degradation of medical animal husbandry wastewater in series with the plant growth device is mainly divided into three parts: the power part, the catalytic part and the recycling part. The power part is composed of a peristaltic pump, which is responsible for pumping the medical animal husbandry wastewater in the storage tank into the catalytic part; the photocatalytic part is assembled by the specific steps in step three; the recycling part is composed of a hydroponic pool, which is responsible for hydroponically cultivating plants with wastewater after photocatalytic degradation to achieve the effect of promoting plant growth. The power part, the catalytic part, and the recycling part are connected by external pipes in turn, fixed with the bottom plate, and checked whether the fixation is loose. If it is loose, it can be reinforced again. Before the test, a sealing and pressure test should be carried out. On the basis of the above parts, an ordinary water storage bottle and a peristaltic pump are connected. After 1 hour of circulation, if there is no leakage and no change in liquid volume, it can be retained for standby. If the above-mentioned leaks occur, readjustment is required.

[0078] Step 5: Performance test of the photocatalytic degradation of medical and livestock wastewater in series with the plant growth device.

[0079] (1) Performance test of catalytic core materials

[0080] The photocatalytic activity of the catalytic core material was evaluated by the removal rate of tetracycline in the tetracycline wastewater as a function of time. The tetracycline degradation test was performed using a 300W xenon lamp with a filter (λ>420nm) added, and the radiation intensity was 100mW·cm -1 In each degradation experiment, the amount of catalyst added was 1 mg·10 mL -1 , the concentration of tetracycline solution is 20 mg·L -1 Before irradiation, the solution was ultrasonicated for 10 min and stirred for 1 h in the dark to reach adsorption equilibrium. After turning on the light, samples were taken every 20 min, and the concentration of the pollutant solution was measured by UV-visible spectrometer.

[0081] (2) Performance testing in laboratory environment

[0082] The device performance test in the laboratory environment was carried out under a 300W xenon lamp with a filter (λ>420nm) and a radiation intensity of 100mW·cm -2 , the ambient temperature is 25°C, and the concentration of tetracycline antibiotic wastewater is 20 mg·L -1 Before irradiation, the tetracycline antibiotic wastewater was ultrasonicated for 10 min. After the light was turned on, samples were taken every 20 min, and the concentration of the pollutant solution was measured by a UV-visible spectrometer.

[0083] (3) Performance test under natural light environment

[0084] The device performance test under natural light environment was carried out outdoors with good ventilation. The outdoor temperature on the test day was 21-24℃, and the radiation intensity of the catalytic part tested by the radiometer was 60-70mW·cm -2 , which is lower than the irradiation intensity under laboratory conditions. Place the device prepared in step 4 in a well-ventilated outdoor place, add tetracycline antibiotic wastewater to the storage bottle, connect the external power supply and peristaltic pump, check for leakage, and perform performance test after the inspection is completed. It should be noted that the plant seeds used for hydroponics to promote growth after degradation solution need to be soaked in water for 6 hours to promote early germination of the seeds.

[0085] After the above steps, the test data of the catalytic core material are as follows: the degradation rate of tetracycline antibiotics within 160 minutes under air conditions is 97%; the degradation rate of tetracycline antibiotics under argon conditions is 51%; the degradation rate of tetracycline antibiotics under laboratory conditions is 96%; the degradation rate of tetracycline antibiotics under natural light conditions is 94%; the roots of plants cultivated hydroponically, the catalytic core material group are more developed and longer than those of the control group.

[0086] The degradation rate under air conditions is much higher than that under argon conditions. In addition to excellent photocatalytic activity, reusability and stability also have a significant impact on the practical industrial application of photocatalysts. Therefore, we conducted cyclic photocatalytic experiments to evaluate the reusability of the catalyst. After 4 cycles, the catalyst was used for 640 minutes, maintaining a degradation rate of 48% under argon conditions and 89% under air conditions, with a performance loss of only 4.4%. This proves that the photodegradation catalyst viologen-based covalent organic framework material has good cyclic stability. In addition, the surface morphology of the catalyst hardly changed before and after use, further proving the stability of the catalyst viologen-based covalent organic framework material.

[0087] The degradation pathway of pollutants under visible light irradiation of photocatalytic materials was inferred using HPLC-MS and ion chromatography. The active species attacked the active site of tetracycline, oxidizing the hydroxyl group and double bonds. Next, further ring opening continued through oxidation and denitrification. As the active site was further attacked by the active species, it gradually degraded into small molecules with a molecular weight of about 100. The photocatalytic process did not stop after decomposing the organic molecules, it moved towards the complete mineralization of the organic matter, forming CO2, H2O, NH4 + and NO3 - .

[0088] Therefore, the test confirmed that the viologen-based covalent organic framework material is a good photocatalytic degradation catalyst. The viologen molecule itself can achieve rapid electron transfer. After modifying the viologen or extending the viologen with other structures, the stability of free radicals and the speed of electron transfer are improved, while the molecular structure is stabilized. Compared with metal oxides, complexes and other molecules, the use of metal elements is avoided, which greatly reduces the cost. The nature of heterogeneous catalysis also makes the material highly recyclable, further improving its cost-effectiveness.

[0089] The present invention conducts relevant tests on the prepared viologen-based covalent organic framework material. The specific test results are shown in the attached Figure 3-7 .

[0090] By the attached Figure 3From the data, it can be seen that the viologen-based covalent organic framework material obtained in the present invention exhibits multiple groups of diffraction peaks at 3-10° (4.4, 5.4, 7.0), and the XRD spectrum obtained in the experiment is consistent with the calculated value of Material Stuido fitting, which further proves that the synthesis method provided by the present invention successfully constructs a viologen-based covalent organic framework material, and the broad peak at about 20 degrees should be a manifestation of layered stacking.

[0091] Attached Figure 4 and attached Figure 5 The transmission electron microscope image and scanning electron microscope image of the viologen-based covalent organic framework material of Example 1 of the present invention show that the material has smooth nanorod and nanosheet structures due to layered stacking, with a width of 0.5-1.0 micrometer.

[0092] Attached Figure 6 This is the solid-state NMR image of the viologen-based covalent organic framework material of Example 1 of the present invention. The asymmetric peak at 170 ppm can be attributed to the carbon atoms in the ternary structure, while the asymmetric peak at 129 ppm can be attributed to the carbon atoms and viologen units near the aromatic ring and the ternary structure, proving that the synthesis method provided by the present invention successfully constructed a viologen-based covalent organic framework material.

[0093] Attached Figure 7 As shown in its thermogravimetric curve, the viologen-based covalent organic framework material remains relatively stable at 500°C and retains about 60% of its initial mass after complete decomposition at 700°C, showing good thermal stability.

[0094] Attached Figure 8 Its XPS diagram further proves the elemental composition and elemental distribution of the viologen-based covalent organic framework material, further proving the successful construction of the material.

[0095] By the attached Fig. 9 The data show that the viologen-based covalent organic framework material provided by the present invention has a good response to light. Fig.10 The data show that the electron paramagnetic resonance spectrum gives a typical free radical signal, and the g factor (2.0055, 2.0024) of the viologen-based covalent organic framework material is almost equal to the g factor (2.0023) of the free electron, indicating the characteristics of the organic free radical. This shows that the viologen-based covalent organic framework material obtained by the present invention has unique optical and electrochemical properties, making it possible to be applied in the field of photocatalysis.

[0096] By the attached Fig.11 The data show that the degradation rate of antibiotic tetracycline was 97% within 160 minutes under air conditions, and 51% under argon conditions; the degradation rate of antibiotic tetracycline in laboratory environment was 96%. Fig.12The data shows that after 4 cycles, the catalyst was used for 640 minutes. Under argon conditions, the organic framework material maintained a 48% degradation rate for the antibiotic tetracycline. Under air conditions, the organic framework material still had an 89% degradation rate for the antibiotic tetracycline, with a performance loss of only 4.4%.

[0097] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A type of viologen-based covalent organic framework material, characterized in that: The structural unit of the viologen-based covalent organic framework material is shown below: In the formula, R1 is Any one of the following, R2 is Any one of .

2. The viologen-based covalent organic framework material according to claim 1, characterized in that: The structural unit is as follows:

3. A method for synthesizing a viologen-based covalent organic framework material as claimed in any one of claims 1 to 2, characterized in that: The viologen-based covalent organic framework material synthesis steps include: dispersing monomer I and monomer II in a mixed solvent, reacting at 110-130° C. for 24-48 hours to obtain a suspension; cooling the suspension to room temperature, washing, drying, and grinding to obtain the viologen-based covalent organic framework material; Wherein, the monomer I is selected from any one of compounds 1 to 3 Monomer II is selected from any one of compounds 4 to 5 4. The method for synthesizing a viologen-based covalent organic framework material according to claim 3, characterized in that: The preparation method of compound 5 in monomer II is as follows: compound 6, compound 7 and copper acetate are dissolved in N,N-dimethylformamide, the obtained mixture is heated to 90-110° C. and stirred for 24-48 hours, cooled to room temperature, dichloromethane is added for precipitation, vacuum filtration is performed for separation, and washing is performed to obtain compound 5.

5. The method for synthesizing the viologen-based covalent organic framework material according to claim 3, characterized in that: The molar ratio of the monomer I to the monomer II is 1:1 to 1:1.

5.

6. The method for synthesizing the viologen-based covalent organic framework material according to claim 4, characterized in that: The molar ratio of compound 6, compound 7 and copper acetate is 20:2:

1.

7. The method for synthesizing the viologen-based covalent organic framework material according to claim 3, characterized in that: The mixed solvent is triethylamine and toluene in a volume ratio of 1:1.

5.

8. Use of the viologen-based covalent organic framework material according to any one of claims 1 to 2 in photocatalytic degradation of antibiotics.

9. Use of the viologen-based covalent organic framework material according to any one of claims 1 to 2 in wastewater treatment.

10. A device for photocatalytic degradation of medical and animal husbandry wastewater and plant growth in series prepared from the viologen-based covalent organic framework material as claimed in claim 1, characterized in that: The photocatalytic part is composed of a metal mesh loaded with a viologen-based covalent organic framework material and loaded into a borosilicate glass hollow tube.

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