Triazole pyridine extractant-hollow tetrazinyl COF composite material as well as preparation method and application thereof
By preparing triazolylpyridine extractant@hollow tetrazine-based COF composite material, the problems of poor adsorbent selectivity and slow kinetics in the separation and recovery of actinides in traditional methods were solved, and efficient and stable separation and recovery of actinides were achieved.
Patent Information
- Application Number
- CN202610140261.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-02
- Publication Date
- 2026-04-24
AI Technical Summary
In existing technologies, solvent extraction generates a large amount of organic waste liquid during the separation and recovery of actinide elements. Traditional adsorbents have low adsorption capacity, slow kinetics, and poor selectivity, making it difficult to effectively combine the structural characteristics of COF with the specific recognition ability of the extractant.
Hollow tetrazine-based COF materials were prepared by stepwise polymerization and alkaline etching using aldehyde-modified SiO2 as a hard template. Triazole pyridine extractant was introduced by pressure difference-concentration method to form a triazole pyridine extractant@hollow tetrazine-based COF composite material. The high specific surface area and strong coordination ability of the extractant were combined to achieve efficient loading and uniform dispersion of the extractant.
It achieves high adsorption capacity, fast adsorption kinetics and excellent selectivity, significantly improving the separation and recovery efficiency of actinides. The material is structurally stable in high acid and high ionic strength environments and has good reusability.
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Figure CN121911375A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of materials preparation technology, and in particular to a triazolylpyridine extractant@hollow tetrazine-based COF composite material, its preparation method, and its application. Background Technology
[0002] With the continued growth of global energy demand and the deepening of the low-carbon transition, nuclear energy, as a clean, efficient, and stable baseload energy source, plays an irreplaceable strategic role in ensuring energy security and achieving "dual carbon" goals. The sustainable development of nuclear energy highly depends on the efficient utilization of nuclear fuel and the safe disposal of radioactive waste. Among these, the efficient separation and recovery of high-value, long-lived actinide elements (such as uranium, thorium, and plutonium) from the fuel is a core technological link in achieving a closed-loop nuclear fuel cycle, reducing the toxicity of high-level radioactive waste, and improving resource utilization.
[0003] Currently, the mainstream technology for the separation and recovery of actinides in industry is solvent extraction. Although it has high separation efficiency, the extraction process generates a large amount of radioactive organic waste liquid, and suffers from problems such as solvent degradation and emulsification, resulting in high environmental burden and subsequent treatment costs. In comparison, solid adsorption can effectively reduce organic waste, but traditional adsorbents such as porous carbon and zeolites generally suffer from low adsorption capacity, slow adsorption kinetics, and poor selectivity for target ions in complex systems. Combining the extractant with highly stable and structurally designable functional porous materials can effectively solve the problems of single function, poor selectivity, and the generation of large amounts of acid liquid in liquid-phase extraction of traditional porous materials.
[0004] Covalent organic frameworks (COFs), with their high specific surface area, ordered pores, excellent structural stability, and designability, provide an ideal material platform for constructing next-generation high-performance adsorbents. Hollow-structured COFs, in particular, combine high specific surface area, short diffusion paths, and cavity enrichment effects, significantly enhancing adsorption kinetics. However, how to stably and densely integrate the excellent structural characteristics of COFs with the specific recognition capabilities of highly efficient extractant molecules remains a challenging problem. Physical impregnation can easily lead to extractant loss, while conventional chemical grafting may clog pores or weaken the material's inherent properties. Summary of the Invention
[0005] Therefore, this invention proposes a triazolylpyridine extractant@hollow tetrazine-based COF composite material, its preparation method, and its application.
[0006] The technical solution of this invention is implemented as follows: A method for preparing a triazolylpyridine extractant@hollow tetrazine-based COF composite material includes the following steps: Preparation of S1 and aldehyde-modified SiO2 Silica nanospheres were ultrasonically dispersed in anhydrous ethanol for 60 min, then triethoxysilyl butyral solution was added, stirred, washed and dried to obtain aldehyde-modified SiO2, denoted as CHO-SiO2. Preparation of silica nanospheres according to the present invention: 30 mL of deionized water, 9 mL of anhydrous ethanol and 6 mL of ammonia water were mixed and stirred at 1000 rpm for 10 min. Then, 45 mL of anhydrous ethanol and 2.55 mL of anhydrous tetraethyl orthosilicate were added and the reaction was continued for 4 h. After centrifugation, the product was washed three times with ethanol and dried at 80 °C for 12 h to obtain silica nanospheres. Preparation of S2 and CHO-SiO2@COF CHO-SiO2 and methyl monomers were added to an organic solvent and subjected to ultrasonic treatment. Then, aldehyde monomers were added and a condensation reaction was carried out to obtain a core-shell composite material CHO-SiO2@COF, in which CHO-SiO2 is the core and COF is the shell. S3, Alkali Etching CHO-SiO2@COF was etched using an alkaline solution to obtain HCOF hollow material; Preparation of S4, triazolylpyridine extractant@hollow tetrazine-based COF composite material The extractant 4,4'-(2,6-pyridinidyl)bis[1 H [-1,2,3-triazole-1-propanol] was added to the ionic liquid, followed by the addition of S3 HCOF hollow material. The mixture was stirred under vacuum, filtered and washed, and then dried under vacuum to obtain triazole pyridine extractant@hollow tetrazine-based COF composite material.
[0007] The preparation process flow diagram is as follows:
[0008] Furthermore, in step S1, the solid-liquid ratio of the silica nanospheres to anhydrous ethanol is 0.8-1:180g / mL; The triethoxysilylbutyraldehyde solution is obtained by mixing triethoxysilylbutyraldehyde and anhydrous ethanol at a volume ratio of 1:40-50; the liquid-solid ratio of the triethoxysilylbutyraldehyde solution to the silica nanospheres is 20.4:0.8-1 mL / g. The stirring was carried out at 600-700 rpm for 6-8 hours, and the drying was carried out at 50-80℃ for 24 hours.
[0009] Furthermore, in step S2, the mass ratio of CHO-SiO2 to methyl monomer and aldehyde monomer is (8-26.9):(4-8):(9.45-18.9).
[0010] Furthermore, the methyl monomer is 3,6-dimethyl-1,2,4,5-tetraazine, and the aldehyde monomer is 2,4,6-tris(4-aldehydephenyl)-1,3,5-triazine.
[0011] Furthermore, in step S2, the solid-liquid ratio of CHO-SiO2 and the organic solvent is 8-26.9:1.357 mg / mL, and the organic solvent is mesitylene, 1,4-dioxane and acetonitrile in a volume ratio of 0.66:0.66:0.037. The ultrasonic treatment is performed at a frequency of 35-45 kHz, a temperature of 25-30°C, a power of 450-550 W, and a duration of 30-240 min.
[0012] Furthermore, in step S2, the condensation reaction also includes the catalyst trifluoroacetic acid, with an addition amount of 0.25-0.30 mL; The condensation reaction is carried out at a heating crystallization temperature of 115-125℃ for 7-9 days.
[0013] Furthermore, in step S3, the solid-liquid ratio of CHO-SiO2@COF to the alkaline solution is 150:400-450 mg / mL, and the alkaline solution is a sodium hydroxide solution with a concentration of 2-3 mol / L; The etching process involves treating the sample at 50-60°C for 5-6 hours, followed by washing until the sample is neutral.
[0014] Furthermore, in step S4, the 4,4'-(2,6-pyridinidyl)bis[1] H The solid-liquid ratio of [-1,2,3-triazole-1-propanol] to the ionic liquid is 15:0.5-2.5 mg / mL; The ionic liquid is 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imine; The solid-liquid ratio of the HCOF hollow material to the ionic liquid is 15:0.5-2.5 mg / mL; The vacuum stirring time is 0.4-12 hours, the washing uses dichloromethane, and the vacuum drying temperature is 50-120°C for 12-24 hours.
[0015] The present invention also provides a triazolylpyridine extractant@hollow tetrazine-based COF composite material, which is prepared by the preparation method described above.
[0016] This invention also provides an application of triazolylpyridine extractant@hollow tetrazine-based COF composite material in the preparation of materials that selectively adsorb thorium ions.
[0017] Compared with the prior art, the beneficial effects of the present invention are: The triazolylpyridine extractant@hollow tetrazine-based COF composite material of the present invention first uses aldehyde-modified SiO2 as a hard template to obtain a tetrazine-based covalent organic framework (COF) material with hollow ethylene linkages through stepwise polymerization and alkaline etching. Then, extractant molecules with specific polydentate coordination structures (containing multiple nitrogen, oxygen heterocycles and hydroxyl groups) are further introduced into the cavity using a pressure-concentration gradient method to obtain the composite material. This composite material effectively overcomes the shortcomings of current solvent extraction methods (generating organic waste liquid) and traditional solid adsorbents (poor selectivity and slow kinetics) by synergistically integrating the high specific surface area and short mass transfer path of the hollow structure, the strong coordination ability of the tetrazine group, and the high selective recognition function of the extractant. The composite material prepared by this invention ultimately exhibits high adsorption capacity, fast adsorption kinetics, excellent selectivity, and good reusability for thorium ions, and has important application value in the field of efficient separation and recovery of actinides in radioactive wastewater.
[0018] Specifically, using aldehyde-modified SiO2 as a hard template not only provides a clear spatial confinement for the synthesis of the material, but its surface aldehyde functional groups can also effectively participate in and guide the subsequent COF polymerization reaction, ensuring the uniform and orderly growth of the core-shell structure, and laying a key foundation for finally obtaining hollow COF materials with complete structure and uniform size. The tetraazine-based carbon-carbon double bond COF, constructed via Knoevenagel condensation, has an ethylene bond (-C=C-) linked COF framework that exhibits superior chemical and solvent stability compared to traditional imine bond COFs. This ensures that the material maintains structural stability in a radioactive aqueous environment with high acidity and high ionic strength. The inherent strong coordinating groups (tetraazine groups) in its framework provide intrinsic, high-density adsorption sites. The hollow porous structure formed by removing the template by alkaline etching has a huge inner cavity and a thin porous shell. This structure not only provides an extremely high specific surface area to load more active sites, but its internal cavity can also act as a "nano reservoir" to pre-enrich ions, while the thin shell significantly shortens the mass transfer path of the target ions to diffuse inside and outside, thereby greatly improving the adsorption kinetics and overall adsorption capacity. This method employs a pressure-concentration gradient method to introduce the extractant into the ionic liquid. Compared to traditional single concentration gradient methods or physical impregnation methods, this approach utilizes the pressure difference generated by a vacuum to drive the ionic liquid (carrying the extractant) to efficiently penetrate deep into the cavity and channels of the hollow COF, achieving uniform, high-load, and robust loading of the extractant within the carrier. This method effectively avoids the problems of extractant aggregation and easy loss on the material surface that are common in traditional physical impregnation methods, and also overcomes the disadvantages of uneven loading and low efficiency in single diffusion (concentration gradient methods), ensuring the stability and durability of the composite material's adsorption performance in practical applications. Attached Figure Description
[0019] Figure 1 This is a synthetic route diagram for the triazolylpyridine extractant@hollow tetrazine-based COF composite material in Example 3.
[0020] Figure 2 The image shows a sample of CHO-SiO2@COF used in this embodiment.
[0021] Figure 3 This is a sample image of the HCOF hollow material used in the embodiment.
[0022] Figure 4 This is a sample image of PyBTA@HCOF used in an embodiment.
[0023] Figure 5 The PXRD spectrum of CHO-SiO2@COF in the example is shown.
[0024] Figure 6 The PXRD spectrum of the HCOF hollow material in the example is shown.
[0025] Figure 7 The PXRD spectrum of PyBTA@HCOF is shown in the example. Figure 8 The image shows a TEM image of the HCOF hollow material used in this embodiment.
[0026] Figure 9 The diagram shows the experimental process of PyBTA@HCOF adsorption performance for thorium under different pH conditions, as an example.
[0027] Figure 10 The adsorption effect of PyBTA@HCOF on Th(IV) under different pH conditions is shown in the example.
[0028] Figure 11 This is a sample image of PyBTA@HCOF from Comparative Example 2.
[0029] Figure 12 This is a sample image of PyBTA@HCOF from Comparative Example 3.
[0030] Figure 13 The diagram shows the regeneration cycle performance of PyBTA@HCOF in this embodiment. Detailed Implementation
[0031] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.
[0032] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.
[0033] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.
[0034] Preparation of silica nanospheres according to the present invention: 30 mL of deionized water, 9 mL of anhydrous ethanol and 6 mL of ammonia water were mixed and stirred at 1000 rpm for 10 min. Then, 45 mL of anhydrous ethanol and 2.55 mL of anhydrous tetraethyl orthosilicate were added and the reaction was continued for 4 h. After centrifugation, the product was washed three times with ethanol and dried at 80 °C for 12 h to obtain silica nanospheres.
[0035] Abbreviated Explanation
[0036] Example - Synthesis of PyBTA@HCOF Preparation of S1, CHO-SiO2 1 g of silica nanospheres were added to 180 mL of anhydrous ethanol and ultrasonically dispersed for 60 min. Then, 20.4 mL of triethoxysilylbutyraldehyde solution (0.4 mL of triethoxysilylbutyraldehyde and 20 mL of anhydrous ethanol) was added, and the mixture was stirred at 1000 rpm for 6 h. The mixture was then filtered, washed with anhydrous ethanol, and vacuum dried for 24 h to obtain CHO-SiO2. Preparation of S2 and CHO-SiO2@COF 18.9 mg CHO-SiO2 and DMTAZ (8 mg, 0.072 mmol) were added to a Pyrex tube, followed by 0.66 mL of mesitylene, 0.66 mL of 1,4-dioxane, and 37 μL of acetonitrile. The reaction was carried out by sonication at 40 kHz, 25 °C, and 500 W for 1 h. After the reaction, 18.9 mg TFPT (0.048 mmol) and 0.292 mL of trifluoroacetic acid were added to the Pyrex tube. The Pyrex tube was then frozen in liquid nitrogen, evacuated and purged with nitrogen three times using a vacuum pump, and then flame-sealed. After cooling to room temperature, the tube was placed in a 120 °C oven for 7 days. After the reaction, the tube was washed five times alternately with methanol and tetrahydrofuran, and then dried under vacuum at 80 °C for 24 h to obtain CHO-SiO2@COF. Sample image is shown below. Figure 2 As shown; S3, Alkali Etching At 50℃, 150 mg of CHO-SiO2@COF was added to 400 mL of 3 mol / L sodium hydroxide solution for etching for 5 h. After centrifugation, the target product was collected, washed with deionized water until pH 7, and vacuum dried at 80℃ for 24 h to obtain HCOF hollow material. Sample image as shown. Figure 3 As shown; Preparation of S4 and PyBTA@HCOF PyBTA (15 mg) was added to 1 mL of TF2N and mixed thoroughly. Then, 15 mg of HCOF hollow material was added, and the mixture was stirred under vacuum for 12 h. The product was collected by filtration, washed five times with dichloromethane, and dried under vacuum at 80 °C for 12 h to obtain PyBTA@HCOF. (Sample image shown). Figure 4 As shown.
[0037] Results Analysis See Figure 5 The PXRD pattern of CHO-SiO2@COF shows obvious characteristic diffraction peaks, indicating the successful synthesis of CHO-SiO2@COF; see also... Figure 6 The PXRD pattern of the HCOF hollow material shows obvious characteristic diffraction peaks, indicating the successful synthesis of the HCOF hollow material; see also... Figure 7 The PXRD spectrum of PyBTA@HCOF shows obvious characteristic diffraction peaks, indicating the successful synthesis of PyBTA@HCOF.
[0038] See Figure 8 The TEM image of the HCOF hollow material shows that the material exhibits a hollow structure.
[0039] Test Example 1 The adsorption performance of PyBTA@HCOF material prepared in the examples on thorium was tested at room temperature and under different pH conditions.
[0040] Experimental method: A 100 ppm thorium-containing solution was used as the test solution. The pH of the test solution was adjusted to 1.0, 2.0, 3.0 and 4.0 by using nitric acid aqueous solution and sodium hydroxide aqueous solution. Then, 2 mg of the PyBTA@HCOF material from the example was added to 6 mL of the test solution for adsorption test. The adsorption time was 24 h.
[0041] The concentration of thorium ions before and after adsorption was determined by ICP-OES. The experimental procedure is shown in the figure below. Figure 9 As shown, the experimental results are as follows: Figure 10 As shown.
[0042] The formula for calculating the adsorption capacity of Th(IV) is as follows:
[0043] Wherein, q e Adsorption capacity, in mg / g; C0 represents the initial concentration of thorium ions, in ppm. C e The concentration of thorium ions after adsorption is expressed in ppm. V is the volume of the thorium solution, in mL; m represents the mass of the COF material, expressed in mg.
[0044] from Figure 10 It can be seen that the PyBTA@HCOF material prepared in the example has the highest adsorption capacity for Th(IV) at pH=4.0, which is 323 mg / g. The PyBTA@HCOF material does not adsorb Th(IV) at pH=1.0, pH=2.0 and pH=3.0.
[0045] Therefore, the subsequent experiments investigated the adsorption performance of the material for Th(IV) under pH=4.0 conditions.
[0046] Comparative Example 1 The difference from the example is that in step S1, CHO-SiO2 is replaced with NH2-SiO2, and in step S2, the order of adding DMTAZ and TFPT is reversed, that is, TFPT is added first and then DMTAZ is added. Otherwise, it is the same as in example 1.
[0047] Comparative Example 2 The difference from the example is that in step S4, stirring under vacuum is replaced by stirring under atmospheric pressure, while the rest is the same as in example 1.
[0048] Comparative Example 3 The difference from the example is that step S4 introduces the extractant by immersion, while the rest is the same as in example 1.
[0049] Specifically, step S4 involves mixing PyBTA (100 mg) with 0.2 mL of methanol and stirring. Then, 5 mg of HCOF is added each time, for a total of 5 additions, totaling 25 mg of HCOF. The mixture is then vacuum dried at 80 °C for 12 h to obtain PyBTA@HCOF.
[0050] Comparative Example 4 The difference from the embodiment is that step S4 is missing, but otherwise it is the same as embodiment 1.
[0051] Test Example 2 Adsorption isotherm experiments were conducted on the PyBTA@HCOF materials prepared in the examples and the materials prepared in Comparative Examples 1-4 at pH=4.0.
[0052] Experimental procedure: Thorium-containing solutions with concentrations ranging from 25 to 500 mg / L were used as adsorption solutions. Then, 2 mg of the PyBTA@HCOF material prepared in the examples and the materials prepared in comparative examples 1-4 were added to 6 mL of adsorption solutions of different concentrations to conduct adsorption isotherm experiments. The adsorption time was 24 h.
[0053] The concentration of thorium ions before and after adsorption was determined by ICP-OES, and the experimental results are shown in Table 1.
[0054] Table 1
[0055] As shown in Table 1, the saturated adsorption capacity of the PyBTA@HCOF material (triazolylpyridine extractant@hollow tetrazine-based COF composite material) prepared in the embodiments of the present invention for Th(IV) is significantly higher than that of Comparative Examples 1-4. Specifically, the decreased adsorption performance of the NH2-SiO2@hollow composite material prepared using NH2-SiO2 as a template in Comparative Example 1 is mainly attributed to the inability of the amino-modified SiO2 surface to effectively bond with the COF precursor and guide ordered nucleation, resulting in reduced structural integrity and crystallinity of the final hollow COF, thus weakening the structural stability and active site exposure of the material. Comparative Example 2 replaced vacuum stirring with atmospheric pressure stirring, i.e., using a single concentration difference method to introduce the extractant. The final prepared material (product as shown in Table 1) Figure 11 The low adsorption performance of the extractant for Th(IV) is due to the inability to achieve uniform and high-load dispersion of the extractant within the hollow structure, resulting in low diffusion efficiency and insufficient loading, which leads to a decrease in the utilization rate of active sites. Comparative Example 3 describes the final material prepared by introducing the extractant via impregnation (products such as...). Figure 12 The adsorption performance of the extractant for Th(IV) is low because it is impossible to achieve uniform and high-load dispersion of the extractant inside the hollow structure. This results in surface enrichment and easy loss, leading to a decrease in the utilization rate of active sites. The decreased adsorption performance of the ethylene-linked hollow tetrazine-based COF material prepared in Comparative Example 4 is due to the lack of synergistic coordination with a specific extractant.
[0056] The data from Comparative Examples 1-4 further demonstrate that, based on the presence of a strong coordinating group (tetraazine), a stable carbon-carbon double bond is used to construct a hollow structure. Combined with the pressure difference-concentration method to introduce a highly loaded and uniformly dispersed extractant, the stability, mass transfer efficiency, and active sites of the material are synergistically improved, exhibiting excellent thorium adsorption performance.
[0057] Test Example 3 The adsorption selectivity of the PyBTA@HCOF material prepared in the example was investigated at pH 4.0 for multi-component adsorption.
[0058] Experimental procedure: Different competing ions Th(IV) and U(VI), Rb(I), La(III), Pr(III), Sm(III), Gd(III), and Lu(III) were coexisted in a mixed solution. The concentration of the competing ions and thorium was 50 ppm. Then, 2 mg of the PyBTA@HCOF material prepared in the example was added to 6 mL of the mixed solution for adsorption test. The adsorption time was 24 h.
[0059] The concentrations of each ion before and after adsorption were determined using ICP-OES.
[0060] The thorium-uranium separation factor of the PyBTA@HCOF material is 310.
[0061] Allocation coefficient:
[0062] Separation coefficient:
[0063] Where C0 is the initial concentration of ions before adsorption, in ppm; C e The concentration of ions after adsorption is expressed in ppm. m: Mass of COF material used, mg; V: Volume of the adsorption solution, mL; Separation coefficient of thorium ions, mL / g; Separation coefficient of competing metal ions, mL / g; The thorium-uranium separation factor of the PyBTA@HCOF material is 310. This experimental result shows that the PyBTA@HCOF material in this embodiment has a very strong ability to recognize and bind thorium ions, and exhibits excellent selective separation performance in a multi-element mixed system. This demonstrates the effectiveness and practical value of the present invention in improving material selectivity through extractant functionalization.
[0064] Test Example 4 The PyBTA@HCOF material prepared in Example 1 was subjected to a recycling performance test.
[0065] Experimental Procedure: At room temperature, 20 mg of PyBTA@HCOF material was mixed with 60 mL of 100 ppm Th(IV) solution for adsorption. Following a solid-liquid ratio of 1:5 mg / mL, the PyBTA@HCOF material, after 24 h of adsorption, was added to a 0.1 mol / L HNO3 aqueous solution and soaked for 24 h. The mixture was filtered, washed with deionized water until the supernatant was neutral, and then vacuum dried to obtain the regenerated sample. The sample was then subjected to the next round of adsorption. The adsorption effect of the material on thorium after 5 cycles of regeneration was measured. The experimental results are as follows: Figure 13 As shown.
[0066] pass Figure 13 It can be seen that the PyBTA@HCOF material of the present invention still has strong thorium adsorption performance after 5 cycles of regeneration, indicating that the PyBTA@HCOF material of the present invention has stable performance, good regeneration performance and high reusability.
[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a triazolylpyridine extractant@hollow tetrazine-based COF composite material, characterized in that, Includes the following steps: Preparation of S1 and aldehyde-modified SiO2 Silica nanospheres were ultrasonically dispersed in anhydrous ethanol, followed by the addition of triethoxysilylbutyraldehyde solution, stirring, washing and drying to obtain aldehyde-modified SiO2, denoted as CHO-SiO2. Preparation of S2 and CHO-SiO2@COF CHO-SiO2 and methyl monomers were added to an organic solvent and subjected to ultrasonic treatment. Then, aldehyde monomers were added and a condensation reaction was carried out to obtain a core-shell composite material CHO-SiO2@COF, in which CHO-SiO2 is the core and COF is the shell. S3, Alkali Etching CHO-SiO2@COF was etched using an alkaline solution to obtain HCOF hollow material; Preparation of S4, triazolylpyridine extractant@hollow tetrazine-based COF composite material The extractant 4,4'-(2,6-pyridinidyl)bis[1 H [-1,2,3-triazol-1-propanol] was added to the ionic liquid, followed by the addition of S3 HCOF hollow material. The mixture was then stirred under vacuum, filtered, washed, and dried under vacuum to obtain triazolylpyridine extractant@hollow tetraazine-based COF composite material.
2. The preparation method of the triazolylpyridine extractant@hollow tetrazine-based COF composite material as described in claim 1, characterized in that, In step S1, the solid-liquid ratio of the silica nanospheres to anhydrous ethanol is 0.8-1:180 g / mL; The triethoxysilylbutyraldehyde solution is obtained by mixing triethoxysilylbutyraldehyde and anhydrous ethanol at a volume ratio of 1:40-50; the liquid-solid ratio of the triethoxysilylbutyraldehyde solution to the silica nanospheres is 20.4:0.8-1 mL / g. The stirring was carried out at 600-700 rpm for 6-8 hours.
3. The preparation method of the triazolylpyridine extractant@hollow tetrazine-based COF composite material as described in claim 1, characterized in that, In step S2, the mass ratio of CHO-SiO2 to methyl monomer and aldehyde monomer is (8-26.9):(4-8):(9.45-18.9).
4. The preparation method of the triazolylpyridine extractant@hollow tetrazine-based COF composite material as described in claim 3, characterized in that, The methyl monomer is 3,6-dimethyl-1,2,4,5-tetraazine, and the aldehyde monomer is 2,4,6-tris(4-aldehydephenyl)-1,3,5-triazine.
5. The preparation method of the triazolylpyridine extractant@hollow tetrazine-based COF composite material as described in claim 1, characterized in that, In step S2, the solid-liquid ratio of CHO-SiO2 and organic solvent is 8-26.9:1.357 mg / mL, and the organic solvent is mesitylene, 1,4-dioxane and acetonitrile in a volume ratio of 0.66:0.66:0.
037. The ultrasonic treatment is performed at a frequency of 35-45 kHz, a temperature of 25-30°C, a power of 450-550 W, and a duration of 30-240 min.
6. The method for preparing a triazolylpyridine extractant@hollow tetrazine-based COF composite material as described in claim 1, characterized in that, In step S2, the condensation reaction further includes the catalyst trifluoroacetic acid, with an addition amount of 0.25-0.30 mL; The condensation reaction is carried out at a heating crystallization temperature of 115-125℃ for 7-9 days.
7. The preparation method of the triazolylpyridine extractant@hollow tetrazine-based COF composite material as described in claim 1, characterized in that, In step S3, the solid-liquid ratio of CHO-SiO2@COF to the alkaline solution is 150:400-450 mg / mL, and the alkaline solution is a sodium hydroxide solution with a concentration of 2-3 mol / L. The etching process is carried out at 50-60℃ for 5-6 hours.
8. The method for preparing a triazolylpyridine extractant@hollow tetrazine-based COF composite material as described in claim 1, characterized in that, In step S4, the 4,4'-(2,6-pyridinidyl)bis[1] H The solid-liquid ratio of [-1,2,3-triazole-1-propanol] to the ionic liquid is 15:0.5-2.5 mg / mL; The ionic liquid is 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imine; The solid-liquid ratio of the HCOF hollow material to the ionic liquid is 15:0.5-2.5 mg / mL.
9. A triazolylpyridine extractant@hollow tetrazine-based COF composite material, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.
10. The application of the triazolylpyridine extractant@hollow tetrazine-based COF composite material according to claim 9 in the preparation of materials that selectively adsorb thorium ions.