Carboxyl / amidoxime functionalized ribbon-shaped beta-keto-enamine covalent organic framework material, preparation method and application of carboxyl / amidoxime functionalized ribbon-shaped beta-keto-enamine covalent organic framework material

Abstract

The invention belongs to the technical field of adsorption materials, and relates to a carboxyl / amidoxime functionalized ribbon-shaped beta-keto-enamine covalent organic framework material, a preparation method and application thereof, the preparation method comprises the following steps: (a) in a catalyst and solvent system, enabling trialdehyde phloroglucinol to react with 2, 5-diaminobenzonitrile and 2, 5-diaminobenzonitrile containing carboxylic acid, sulfonic acid or phosphate groups to obtain a covalent organic framework material; the preparation method comprises the following steps: carrying out condensation reaction on 2, 5-diaminobenzene derivatives to form a ribbon-shaped covalent organic framework material containing carboxyl and nitrile groups; and (b) carrying out oximation reaction, and converting the cyano group into an amidoxime group to obtain the carboxyl / amidoxime functionalized ribbon-shaped beta-keto-enamine covalent organic framework material. According to the carboxyl / amidoxime functionalized ribbon-shaped beta-ketoenamine covalent organic framework material disclosed by the invention, the adsorption capacity of the material is improved, the selectivity to uranyl ions is improved, the material is an adsorbent material with excellent adsorption performance to uranium, and the practical application of the covalent organic framework material in the field of extraction of uranium from seawater is promoted.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of adsorption materials, and particularly relates to a carboxyl / amidoxime functionalized ribbon-like beta-ketoenamine covalent organic framework material, a preparation method and application thereof. BACKGROUND

[0002] One of the important challenges facing human society in the 21st century is the transition to clean energy with deep decarbonization and sustainable development. Nuclear energy has the advantages of high energy density, low carbon release and continuous and stable power supply, and has been widely recognized as a mature and safe technology. The sufficient supply of uranium resources is the premise and foundation guarantee for the sustainable development of the nuclear industry. The reserves of natural uranium on land are limited and there is a certain pollution to the environment in the mining process. The total reserves of uranium in seawater are about 4.5 billion tons, which is 1000 times the proven reserves of uranium ore on land, and the reserves of uranium in seawater are enough to guarantee the long-term stable operation of nuclear power. Therefore, it is urgent to develop new materials and new technologies for extracting uranium from seawater to meet the growing demand for uranium resources.

[0003] In recent years, nano-porous materials such as porous carbon materials, hydrogels, porous organic polymers, porous aromatic skeletons, hydrogen-bonded organic frameworks, and metal-organic frameworks have been applied to uranium extraction from seawater. However, their overall performance is not satisfactory, and the main disadvantages are poor adsorption capacity, poor stability, slow kinetics, poor biopollution resistance, and poor mass transfer ability due to disordered structure, which greatly limits their practical application in uranium extraction from seawater.

[0004] Covalent organic framework materials (COFs) are composed of covalent bonds, have a predictable chemical structure, excellent stability, large specific surface area, and are easy to modify, and have been applied to the field of uranium extraction from seawater in recent years. Although the open 1D channel structure of COFs is beneficial to the transmission of target ions. However, the utilization of active sites in the deep channels of bulk COFs is still limited.

[0005] Therefore, it is necessary to develop a COF with different morphology to improve the adsorption performance of COF for uranium and provide a feasible solution for improving the performance of uranium extraction from seawater. SUMMARY

[0006] The present application provides a carboxyl / amidoxime functionalized ribbon-like beta-ketoenamine covalent organic framework material, a preparation method and application thereof, which solves the problems in the prior art. The specific technical solutions are as follows: The first object of the present application is to provide a preparation method of a carboxyl / amidoxime functionalized ribbon-like beta-ketoenamine covalent organic framework material, comprising the following steps: (a) condensing a tri-aldehyde phloroglucinol with 2,5-diaminobenzonitrile and 2,5-diaminobenzene derivatives in a catalyst and solvent system to form a tape-like covalent organic framework material comprising carboxyl and nitrile groups; the 2,5-diaminobenzene derivatives contain carboxylic acid, sulfonic acid or phosphoric acid groups; (b) oximating the tape-like covalent organic framework material to convert the cyano groups into amidoxime groups to obtain the carboxyl / amidoxime functionalized tape-like beta-ketoenamine covalent organic framework material.

[0007] The present application first synthesizes a tape-like covalent organic framework material with a nanoscale tape-like micro-morphology by a hydrothermal method, and then converts cyano groups into amidoxime groups by oximation to obtain a carboxyl / amidoxime functionalized tape-like beta-ketoenamine covalent organic framework material.

[0008] The present application regulates a microscale block-like covalent organic framework into a nanoscale tape-like morphology, which is very beneficial to efficient use of active sites in COFs and improves the adsorption performance of the material; the amidoxime group is a functional group that can effectively chelate uranyl carbonate ions, and the synergistic effect of the amidoxime group and the carboxylic acid group with the beta-ketoenamine structure on the COF skeleton can further enhance the recognition ability of uranium to achieve efficient adsorption of uranyl; the carboxyl / amidoxime functionalized tape-like beta-ketoenamine covalent organic framework material improves the adsorption capacity of COFs and improves the selectivity for uranyl ions, and is an excellent adsorbent material for extracting uranium.

[0009] Further, the 2,5-diaminobenzene derivatives are one or more of 2,5-diaminobenzoic acid, 2,5-diaminobenzenesulfonic acid, and (2,5-diaminophenyl)phosphoric acid.

[0010] Further, in step (a), the solvent is a mixed solvent of mesitylene and 1,4-dioxane; and the catalyst is acetic acid.

[0011] Further, in step (a), the total amount of tri-aldehyde phloroglucinol, 2,5-diaminobenzonitrile and 2,5-diaminobenzene derivatives and the mass-volume ratio of the solvent are 21-23 mg:1 mL.

[0012] Further, in step (a), the molar ratio of tri-aldehyde phloroglucinol, 2,5-diaminobenzonitrile and 2,5-diaminobenzene derivatives is 2:(1-2):(1-2), and the preferred molar ratio is 2:1:2.

[0013] Further, in step (a), the solvent is a mixed solvent of mesitylene and 1,4-dioxane in a volume ratio of (7~13):(13~7); the concentration of the catalyst is (3~9) mol / L, and the volume ratio of the catalyst to the solvent is 1:(8~12), preferably 1:10.

[0014] Specifically, the preparation method of the ribbon-like covalent organic framework material includes the following steps: Step a1: The reaction raw materials trialdehyde phloroglucinol, 2,5-diaminobenzonitrile and 2,5-diaminobenzene derivative are mixed with solvent and catalyst, and ultrasonically treated to obtain a uniformly mixed first mixture. Step a2: The first mixture is subjected to multiple freeze-pump-thaw degassing cycles to remove air and dissolved gases from the solvent, and then sealed with a flame to obtain the second mixture; Step a3: The second mixture is subjected to a reaction at room temperature for 1.5 to 3 hours; then placed at 110 to 130°C for 3 to 5 days to obtain the third mixture. The mixture is then separated into solid and liquid components, washed, and vacuum dried to obtain a ribbon-like covalent organic framework material containing carboxyl and nitrile groups.

[0015] Specifically, the oxime reaction in step (b) is as follows: the ribbon-like covalent organic framework material, hydroxylamine hydrochloride, trimethylamine and methanol are mixed and reacted at 70~80℃ for 20~30h to obtain a product mixture. The mixture is then separated into solid and liquid components, washed and vacuum dried to obtain the carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material.

[0016] More specifically, the mass ratio of the ribbon-like covalent organic framework material, hydroxylamine hydrochloride, and trimethylamine is 10:(5~7):(8~10); the volume mass ratio of methanol to the total amount of the ribbon-like covalent organic framework material, hydroxylamine hydrochloride, and trimethylamine is 1~1.2 mL:1 g.

[0017] More specifically, the first mixture is frozen by liquid nitrogen; and washed with tetrahydrofuran and methanol.

[0018] The second objective of this invention is to provide a carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material, prepared by the above-mentioned method for preparing carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material.

[0019] A third objective of this invention is to provide the application of the above-mentioned carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material in seawater uranium extraction.

[0020] In some application embodiments provided by this invention, the above-mentioned carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material was added to uranium-containing aqueous solutions and uranium-containing natural seawater, respectively, for experiments. The adsorbed suspension was filtered through a 0.22 μm microporous membrane. The uranium content in the deionized water with added uranium was 4-48 ppm, and the uranium content in the natural seawater with added uranium was 1 ppm and 330 ppb, respectively. Preferably, the amount of the carboxyl / mercaptooxime-functionalized β-ketoenamine covalent organic framework material added was 0.04 g / L. The above-mentioned carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material can reduce the concentration of uranyl ions in uranium-containing natural seawater to only 7.6 ppb, with a removal rate of up to 99.4%, achieving deep purification of uranium in seawater.

[0021] The beneficial effects of this invention are as follows: This invention provides a method for preparing carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework materials. First, a hydrothermal method is used to control the growth direction of COFs by utilizing the difference in interaction forces between the monomer and the solvent, thus synthesizing ribbon-like covalent organic framework materials with a nanoscale ribbon-like microstructure. These ribbon-like covalent organic framework materials exhibit excellent crystallinity and regular internal channels; their specific surface area is approximately 600 m² / s. 2 / g, with a large specific surface area; it plays an important role in promoting the transport effect of uranyl ions; then, the cyano group is converted into a methylamine oxime group through an oxime reaction to obtain a carboxyl / methylamine oxime-functionalized ribbon-like β-ketoenamine covalent organic framework material.

[0022] The carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material of this invention improves the adsorption capacity and selectivity for uranyl ions, exhibiting excellent adsorption performance for uranium. It is an excellent adsorbent material for uranium extraction, promoting the practical application of covalent organic framework materials in the field of seawater uranium extraction. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a synthetic route diagram for preparing carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework materials according to Example 1 of the present invention; Figure 2 The TpDa-COOH prepared in Example 1 of this invention 66Powder X-ray diffraction pattern (left) and simulated structure diagram (right); Figure 3 The reactants in Example 1 of this invention are TpDa-COOH 66 and TpDa-COOH 66 Fourier transform infrared spectrum of -AO; Figure 4 It is the TpDa-COOH prepared in Example 1 of this invention. 66 and TpDa-COOH 66 -AO solid-state NMR 13 C spectrum; Figure 5 It is the TpDa-COOH prepared in Example 1 of this invention. 66 and TpDa-COOH 66 - AO nitrogen adsorption-desorption isotherm and pore size distribution diagram; Figure 6 It is the TpDa-COOH prepared in Example 1 of this invention. 66 TpDa-COOH 66 -AO and contrast agent TpDa-CN 100 TpDa-CN 100 -A scanning electron microscope image of AO; (a)TpDa-CN 100 (b) TpDa-COOH 66 (c) TpDa-CN 100 Local magnification; (d) TpDa-COOH 66 Local magnification; (e)TpDa-CN 100 -AO;(f)TpDa-COOH 66 -AO; Figure 7 It is the TpDa-COOH prepared in Example 1 of this invention. 66 - Surface potential and water contact angle of AO; Figure 8 It is the TpDa-COOH prepared in Example 1 of this invention. 66 Adsorption kinetics diagram (a) and saturated adsorption capacity diagram (b) of -AO. Figure 9 It is the TpDa-COOH prepared in Example 1 of this invention. 66 Adsorption performance of -AO in solutions at different pH values; Figure 10 It is the TpDa-COOH prepared in Example 1 of this invention. 66 Adsorption performance of AO in NaCl solutions of different concentrations; Figure 11It is the TpDa-COOH prepared in Example 1 of this invention. 66 -AO demonstrates its deep purification performance in real seawater. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] Unless otherwise specified in the embodiments or comparative examples of this invention, the techniques or conditions described in the literature in this field shall be followed, or the product instructions shall be followed. Unless otherwise specified, the reagents or instruments used are all conventional products that can be purchased from legitimate channels.

[0027] Example 1: A method for preparing a carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material includes the following steps: Step 1: Weigh 21.0 mg of trialdehyde phloroglucinol (Tp), 15.2 mg of 2,5-diaminobenzoic acid (Da-COOH) and 6.7 mg of 2,5-diaminobenzonitrile (Da-CN) as reactants and place them in a glass reactor. Then add 0.7 mL of mesitylene, 1.3 mL of 1,4-dioxane and 0.2 mL of 6M acetic acid. Then sonicate the mixture for 10 minutes to obtain a homogeneous first mixture. Step 2: Freeze the first mixture in liquid nitrogen, and remove air and dissolved gases from the solvent through three freezing-pumping-thawing and degassing cycles. Then, seal the mixture with a flame to obtain the second mixture. Step 3: The second mixture was allowed to mature at room temperature for 2 hours; then it was placed at 120°C for 3 days to obtain the third mixture. After cooling to room temperature, the solid in the mixture was collected, washed with tetrahydrofuran and methanol, and vacuum dried at 60°C for 12 hours to obtain a reddish-brown powdery ribbon-like covalent organic framework material, named TpDa-COOH. 66 ; Step 4: Weigh 200 mg TpDa-COOH6, 84 mg solid hydroxylamine hydrochloride, and 120 mg trimethylamine solution into 6.0 mL of methanol solution in a Schlenk reactor. Sonicate the mixture for 15 minutes, then heat and stir in a 75°C oil bath for 2 hours. After cooling to room temperature, add another 42 mg solid hydroxylamine hydrochloride and 60 mg trimethylamine solution to the mixture. Place the reactor in a 75°C oil bath and stir for 22 hours. After cooling to room temperature, collect the solid from the mixture, wash with deionized water and methanol, and vacuum dry at 60°C for 12 hours to obtain a brownish-red carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material, named TpDa-COOH. 66 -AO, synthesis route as follows Figure 1 As shown.

[0028] The TpDa-COOH was determined using X-ray powder diffraction (PXRD) and Materials Studio (2019) simulations. 66 Crystal structure. For example... Figure 2 As shown, the diffraction peak at 4.65° corresponds to the (100) crystal plane. Possible stacking modes were simulated using Materials Studio (2019) software. The structural model was refined using Pawley based on experimental data, and the results indicate that TpDa-COOH... 66 hexagonal unit cell P Space group 1, cell parameters a = 45.3173, b = 29.9461 Å, and c = 7.0826 Å, α = 90.9008°, β = 82.7652°, and γ = 120.567° (R p =3.63%, R wp =2.68%).

[0029] Fourier transform infrared spectroscopy (FT-IR) was used to verify the chemical structure and composition. For example... Figure 3 As shown, the monomer contains NH (~3300-3400 cm⁻¹). -1 -CH(2894cm) -1 ) and -C=O(1645cm -1 The stretching vibrations of -NH2 and -CHO almost completely disappeared, indicating a high degree of condensation between them; TpDa-COOH 66 Medium to 1700cm -1 and 2228cm -1 The vibration signal is attributed to the characteristic signals of -COOH and -CN, confirming that TpDa-COOH 66 It contains two groups; TpDa-COOH 66Fourier transform infrared spectroscopy of -AO showed that the -CN signal completely disappeared, while the -COOH peak showed a significant red shift, indicating that the cyano group was completely converted into a metamine oxime group, and that there may be an interaction with the carboxylic acid group. Furthermore, at 1582 cm⁻¹... -1 1443cm -1 The characteristic peak of the β-keto-enamine bond at 1256 cm⁻¹ showed no significant change, proving that TpDa-COOH 66 It has excellent structural stability.

[0030] use 13 Solid-state NMR spectroscopy of C further clarified the structure of COFs. For example... Figure 4 As shown, the signals at ~184.1 ppm and 107.6 ppm are attributed to the -C=O and -C=C signals in the β-ketoenamine structure, respectively, and the signals did not change significantly after oximeization, confirming that TpDa-COOH 66 The structure is a more stable β-ketoenamine. The signal at ~166.8 ppm is the -COOH signal; after oximeization, a new peak appears at ~168.8 ppm, which is attributed to the -C=N signal, confirming that -CN was successfully converted into a methylamine oxime group.

[0031] The TpDa-COOH group was investigated using N2 adsorption-desorption isotherms at 77 K. 66 and TpDa-COOH 66 -The inherent porosity of AO, such as Figure 5 As shown, TpDa-COOH 66 and TpDa-COOH 66 The Brunauer-Emmett-Teller surface area of ​​-AO is 592 m². 2 ·g −1 and 285m 2 ·g –1 Pore ​​size distribution analysis based on the nonlocal density functional theory (NLDFT) model shows that TpDa-COOH 66 and TpDa-COOH 66 The pore size distribution of -AO is concentrated at ~1.2 nm.

[0032] The microstructure of COFs was observed using scanning electron microscopy (SEM). The morphology of the COFs without carboxylic acid induction was named TpDa-CN. 100 The oxime-modified COF structure is named TpDa-CN. 100 -AO is used to compare the microscopic morphological changes caused by the introduction of carboxylic acid groups. For example... Figure 6 As shown, TpDa-CN 100The morphology is a tightly packed, bulk structure, ranging in size from a few micrometers to tens of micrometers. Magnified images show a surface structure of sheet-like bands approximately several hundred nanometers in size; the morphology does not change significantly after oxime amine formation. TpDa-COOH 66 The image shows a sheet-like structure formed by the cross-linking of filamentous fibers, with a size of tens of micrometers; the magnified image shows that the size of the filamentous fibers is about tens of nanometers, and they are cross-linked; after oxime treatment, the material exhibits a more obvious change in morphology and structure, but the filamentous morphology is still visible.

[0033] We can further understand the fundamental properties of materials by examining surface potential and contact angle. For example... Figure 7 As shown in (a), TpDa-COOH 66 -AO surfaces become negatively charged after pH values ​​exceed 4.00, whereas they were positively charged before pH values. Figure 7 (b) Displaying TpDa-COOH 66 -AO is a hydrophilic property, which is beneficial for the extraction of target uranyl ions from seawater.

[0034] Example 2: Compared with Example 1, the only difference is that 15.2 mg of 2,5-diaminobenzoic acid is replaced with 18.8 mg of 2,5-diaminobenzenesulfonic acid, and the amount of mesitylene is 0.8 mL.

[0035] Example 3: Compared with Example 1, the only difference is that the amount of 2,5-diaminobenzoic acid was reduced from 15.2 mg to 7.6 mg, while the amount of 2,5-diaminobenzonitrile was increased to 13.3 mg, and the amounts of mesitylene and 1,4-dioxane were both 1.0 mL.

[0036] Application Examples: The application of the carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material prepared in Example 1 in seawater uranium extraction was tested. Adsorption kinetics test: 200 mL of uranium solution with a concentration of 20 ppm was prepared using ultrapure water, and then the pH of the solution was adjusted to 5.00. Figure 8 As shown in (a). 8.0 mg TpDa-COOH was added. 66 -AO was subjected to adsorption experiments at 25℃ with continuous stirring for 24 hours. At different time intervals during this period, 1 mL of solution was taken, the insoluble residue was filtered, and the concentration of uranyl ions in the filtrate was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The adsorption capacity was then calculated. TpDa-COOH 66 -AO adsorbed uranyl ions for 12 h to reach approximately 91% of adsorption equilibrium, and the adsorption capacity after 24 h was 276 mg / g. Fitting with pseudo-first-order and pseudo-second-order kinetic models showed that TpDa-COOH...66 The adsorption of uranyl ions by -AO is a chemisorption.

[0037] Saturated adsorption capacity test: Uranium solutions with concentrations of 4, 8, 16, 24, 36, and 48 ppm were prepared using ultrapure water, and the pH of the solutions was then adjusted to 5.00. Figure 8 As shown in (b). Take 100 mL of solutions with different initial uranium concentrations into a plastic bottle, and then add 4.0 mg TpDa-COOH. 66 -AO was subjected to adsorption experiments at 25℃ with stirring for 24 hours. After adsorption, the insoluble matter was filtered out, and the concentration of uranyl ions in the filtrate was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The adsorption capacity, TpDa-COOH, was calculated. 66 -AO exhibits a peak adsorption capacity of 442 mg / g for uranyl ions. Fitting the adsorption isotherms using Langmuir and Freundlich models indicates that the active adsorption sites are uniformly distributed on the material surface, with TpDa-COOH... 66 -AO adsorption of uranyl ions is a multilayer adsorption.

[0038] pH Effect: To further evaluate the adsorption performance of the material, adsorption was carried out in uranyl solutions with different pH values, ranging from pH 3.00 to 9.00 ± 0.02. 4.0 mg TpDa-COOH was used... 66 -AO was added to 100 mL of uranyl solution, with an initial concentration of ~20 ppm. For example... Figure 9 As shown, the maximum adsorption capacity was obtained at pH 8.0, indicating that TpDa-COOH 66 -AO has significant advantages in extracting uranium from seawater.

[0039] Salinity Influence: A key factor in uranium extraction from seawater is the high concentration of NaCl in the seawater medium, which affects the adsorption performance of materials. On one hand, high salinity causes pore shrinkage, hindering the transport of uranyl ions. On the other hand, NaCl... + As an interfering ion, it competes with uranyl ions. To further evaluate the material's suitability in seawater, its adsorption performance under high-salt conditions was assessed. 4.0 mg TpDa-COOH 66 -AO was added to 100 mL of uranyl solution containing varying NaCl concentrations at ~20 ppm. For example... Figure 10 As shown, under 0.5M NaCl conditions, TpDa-COOH 66 The adsorption capacity of -AO was 147 mg / g, a decrease of approximately 27.8% from the initial value. Although the adsorption performance was reduced, it was still considerable.

[0040] Natural seawater adsorption experiment: Uranyl ions (~1 ppm) were added to real seawater for testing. The method was as follows: seawater was filtered through a 0.22 μm aqueous filter membrane to remove insoluble substances, such as particulate matter. The seawater used in the experiment came from the South China Sea (Haikou, Hainan). 100 mL of uranium-added seawater was placed in a plastic bottle, with a solid-liquid ratio of 0.04 g / L. The process was carried out at 25 °C to simulate deep purification of uranium in real seawater. The uranium concentration in the solution was determined using ICP-MS, and the change in uranium concentration over time was detected. Figure 11 TpDa-COOH 66 -AO's deep purification capability in uranium-containing natural seawater reduced the concentration of uranium ions in the spiked natural seawater to below the World Health Organization standard (30 ppb) after 4 hours, and the concentration of uranium ions was only 7.6 ppb after 12 hours, with a removal rate of up to 99.4%, thus achieving deep purification of uranium in seawater.

[0041] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material, characterized in that, Includes the following steps: (a) In a catalyst and solvent system, trialdehyde phloroglucinol is condensed with 2,5-diaminobenzonitrile and a 2,5-diaminobenzene derivative to form a ribbon-like covalent organic framework material containing carboxyl and nitrile groups; wherein the 2,5-diaminobenzene derivative contains carboxylic acid, sulfonic acid or phosphate groups. (b) The ribbon-like covalent organic framework material is subjected to an oxime reaction to convert the cyano group into a methylamine oxime group, thereby obtaining the carboxyl / methylamine oxime-functionalized ribbon-like β-ketoenamine covalent organic framework material.

2. The method for preparing the carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material according to claim 1, characterized in that, In step (a), the 2,5-diaminobenzene derivative is one or more of 2,5-diaminobenzoic acid, 2,5-diaminobenzenesulfonic acid, and (2,5-diaminophenyl)phosphoric acid.

3. The method for preparing the carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material according to claim 1, characterized in that, In step (a), the solvent is a mixture of mesitylene and 1,4-dioxane; the catalyst is acetic acid.

4. The method for preparing the carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material according to claim 1, characterized in that, In step (a), the total amount of trialdehyde phloroglucinol, 2,5-diaminobenzonitrile and 2,5-diaminobenzene derivative and the mass-volume ratio of solvent are 21~23 mg: 1 mL; the molar ratio of trialdehyde phloroglucinol, 2,5-diaminobenzonitrile and 2,5-diaminobenzene derivative is 2: (1~2): (1~2), and the preferred molar ratio is 2:1:

2.

5. The method for preparing the carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material according to claim 2, characterized in that, In step (a), the solvent is a mixture of mesitylene and 1,4-dioxane in a volume ratio of (7~13):(13~7); the concentration of the catalyst is (3~9) mol / L, and the volume ratio of the catalyst to the solvent is 1:(8~12).

6. The method for preparing the carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material according to claim 1, characterized in that, A method for preparing ribbon-like covalent organic framework materials includes the following steps: Step a1: The reaction raw materials trialdehyde phloroglucinol, 2,5-diaminobenzonitrile and 2,5-diaminobenzene derivative are mixed with solvent and catalyst, and ultrasonically treated to obtain a uniformly mixed first mixture. Step a2: The first mixture is subjected to multiple freeze-pump-thaw degassing cycles to remove air and dissolved gases from the solvent, and then sealed with a flame to obtain the second mixture; Step a3: The second mixture is subjected to a reaction at room temperature for 1.5 to 3 hours; then placed at 110 to 130°C for 3 to 5 days to obtain the third mixture. The mixture is then separated into solid and liquid components, washed, and vacuum dried to obtain a ribbon-like covalent organic framework material containing carboxyl and nitrile groups.

7. The method for preparing the carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material according to claim 6, characterized in that, The oxime reaction in step (b) is as follows: ribbon-like covalent organic framework material, hydroxylamine hydrochloride, trimethylamine and methanol are mixed and reacted at 70~80℃ for 20~30h to obtain a product mixture. Solid-liquid separation, washing and vacuum drying are performed to obtain carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material.

8. The method for preparing the carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material according to claim 7, characterized in that, The mass ratio of ribbon-like covalent organic framework material, hydroxylamine hydrochloride, and trimethylamine is 10:(5~7):(8~10); the volume mass ratio of methanol to the total amount of ribbon-like covalent organic framework material, hydroxylamine hydrochloride, and trimethylamine is 1~1.2 mL:1 g.

9. A carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material, characterized in that, It is prepared by the method for preparing carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material according to any one of claims 1 to 8.

10. The application of a carboxyl / mercaptooxime-functionalized ribbon-like β-ketoenamine covalent organic framework material as described in claim 9 in seawater uranium extraction.

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