Covalent organic framework material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of porous organic materials, and particularly relates to a covalent organic framework material and a preparation method and application thereof.The covalent organic framework material is obtained through an ammonia-aldehyde condensation reaction of 1, 3, 5-benzene triformyl hydrazine and 2, 5-divinyl-1, 4-phthalaldehyde at the high temperature, meanwhile, azodiisobutyronitrile (AIBN) is used as an initiator, and through the 1, 3, 5-benzene triformyl hydrazine and the 2, 5-divinyl-1, 4-phthalaldehyde, the covalent organic framework material is prepared. 2-ethanedithiol and vinyl on the surface of COFBTH-DVa are subjected to a click reaction, and anchoring of sulfydryl on the surface of COF and the inner wall of a pore channel is achieved; according to the SH-COFBTH-DVa material and the preparation method thereof, the SH-COFBTH-DVa material has the advantages that the SH-COFBTH-DVa material is modified by the sulfydryl, the SH-COFBTH-DVa material is modified by the sulfydryl, multiple HMIs adsorption sites can be given to the SH-COFBTH-DVa by the-N-N-sites rich in the COFBTH-DVa material, the SH-COFBTH-DVa material, and the SH-COFBTH-DVa material has excellent HMIs adsorption performance, and particularly, the SH

Description

Technical Field

[0001] The invention belongs to the technical field of porous organic materials, and in particular relates to a covalent organic framework material and a preparation method and application thereof. Background Art

[0002] Covalent organic frameworks (COFs) are porous crystalline polymer materials formed by organic molecules connected by covalent bonds. They are widely used in adsorption, energy storage, drug release and catalysis due to their large specific surface area, ordered pore channels, excellent thermal and chemical stability, easy functionalization, and controllable frameworks. Since COFs show good application prospects in the adsorption and removal of heavy metal ions (HMIs), many new COFs have been designed and synthesized for the adsorption and removal of HMIs. However, the limited adsorption functional sites severely limit the adsorption performance of COFs on HMIs. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a covalent organic framework material so that the prepared COFs have multiple adsorption functional sites, thereby effectively avoiding the problem of poor adsorption performance of COFs due to insufficient surface adsorption sites, and providing a technical basis for the rapid and efficient adsorption and removal of HMIs using COFs.

[0004] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing a covalent organic framework material comprises the following steps: (1) 1,3,5-benzenetricarboxylic acid hydrazide (BTH) and 2,5-divinyl-1,4-benzenedicarbaldehyde (DVa) were separately dispersed in a mixed solution of 1,4-dioxane and mesitylene and dissolved by ultrasonication; Subsequently, the two solutions were transferred to a test tube, homogenized by ultrasound, and then the acetic acid solution was added; After several (three or more) freeze-thaw cycles, the tubes (Shrek tubes) were degassed and placed in an oil bath at 120°C to 125°C for reaction; (2) The product of the oil bath reaction was washed with N,N-dimethylformamide, the precipitate obtained by washing was soaked in tetrahydrofuran, and then vacuum dried to obtain (yellow powder) COF BTH-DVa Material; (3) COF BTH-DVaThe material and azobisisobutyronitrile (AIBN) were transferred to a clean test tube, and then 1,2-ethanedithiol was added. The reaction was stirred at 80°C to 85°C in an atmosphere of nitrogen protection. The product of the stirred reaction was then washed with acetone, and the precipitate obtained by washing was vacuum dried to obtain SH-COF BTH-DVa Material.

[0005] In a preferred example, in step (1), the mass ratio of 1,3,5-benzenetricarboxylic acid hydrazide to 2,5-divinyl-1,4-benzenedicarbaldehyde is 25-26:27-28, and the mass volume ratio of 1,3,5-benzenetricarboxylic acid hydrazide to the mixed solution of 1,4-dioxane and mesitylene is 42g-43g:1L.

[0006] In a preferred example, the volume ratio of 1,4-dioxane to mesitylene is 1:1.

[0007] In a preferred example, in step (1), the mass volume ratio of 1,3,5-benzenetricarboxylic acid hydrazide to the acetic acid solution is 42 g to 43 g:1 L, and the concentration of the acetic acid solution is 6 mol / L.

[0008] In a preferred example, in step (1), the oil bath reaction time is 72 h to 75 h.

[0009] In a preferred example, in step (2), the soaking time in tetrahydrofuran is 8 h to 12 h.

[0010] In a preferred example, step (3), COF BTH-DVa The mass ratio of the material to azobisisobutyronitrile is 4:1, COF BTH-DVa The mass volume ratio of the material to 1,2-ethanedithiol is 25g:1L.

[0011] In a preferred example, in step (3), the stirring reaction time is 48 h to 50 h.

[0012] Through the above method, SH-COF was successfully prepared BTH-DVa Materials, the SH-COF BTH-DVa The material is obtained by the condensation reaction of 1,3,5-benzenetricarboxylic acid hydrazide and 2,5-divinyl-1,4-benzenedicarboxylic acid at high temperature. At the same time, azobisisobutyronitrile (AIBN) is used as an initiator to react with 1,2-ethanedithiol and COF BTH-DVa The vinyl groups on the surface undergo click reactions, which enable the thiol groups to be anchored on the COF surface and the inner wall of the pores. BTH-DVa The abundant -NN- sites and post-modified thiol groups will endow SH-COF BTH-DVa Multiple HMIs adsorption sites make SH-COF BTH-DVaThe material exhibits excellent adsorption performance for HMIs, which is specifically manifested in SH-COF BTH-DVa The material can realize Pb in aqueous solution 2+ Efficient and fast removal.

[0013] Based on a general inventive concept, another object of the present invention is to provide a covalent organic framework material having multiple adsorption sites prepared by the above preparation method and its application in the adsorption and removal of heavy metal ions, preferably for Pb in aqueous solution. 2+ adsorption removal.

[0014] Compared with the prior art, the covalent organic framework material SH-COF prepared by the method of the present invention is BTH-DVa Due to the introduction of multiple adsorption functional sites, COFs are endowed with excellent heavy metal ion adsorption performance, realizing the rapid and efficient removal of heavy metal ions in the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 SH-COF prepared in Example 1 BTH-DVa Scanning electron microscope image of the material (scale bar is 1μm, detection environment: thermoluminescence detector, high voltage 10.00KV, working distance 5.0mm, magnification 120000 times, spot size 4.0).

[0016] Figure 2 BTH, DVa, COF BTH-DVa and SH-COF BTH-DVa Fourier infrared curve.

[0017] Figure 3 COF BTH-DVa and SH-COF BTH-DVa Pb 2+ The adsorption isotherm.

[0018] Figure 4 COF BTH-DVa and SH-COF BTH-DVa Pb 2+ The adsorption equilibrium data were fitted with the Langmuir adsorption model.

[0019] Figure 5 COF BTH-DVa and SH-COF BTH-DVa Pb 2+ The adsorption kinetics performance curve.

[0020] Figure 6 COF BTH-DVa and SH-COF BTH-Dva Adsorption of Pb 2+ Pseudo-second-order kinetics fitting diagram. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in conjunction with specific embodiments, but the present invention is not limited to these embodiments. It should be noted that, under the premise of not conflicting, the embodiments described below or the technical features can be arbitrarily combined to form new embodiments. In the present invention, unless otherwise specified, all parts and percentages are mass units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, if not otherwise specified, are conventional methods in the art.

[0022] As used herein, the terms "comprises," "including," "contains," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0023] When the amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range limited by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether this range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc. When a numerical range is described in this article, unless otherwise stated, this range is intended to include its end values ​​and all integers and fractions within this range.

[0024] Example 1

[0025] A method for preparing a covalent organic framework material comprises the following steps: (1) First, 25.2 mg of 1,3,5-benzenetricarboxylic acid hydrazide (BTH) and 27.9 mg of 2,5-divinyl-1,4-benzenedicarbaldehyde (DVa) were dissolved in 3 mL of a mixed solution of 1,4-dioxane and mesitylene, and dissolved by ultrasonication; The volume ratio of 1,4-dioxane to mesitylene is 1:1; The two solutions were then transferred to a Shrek tube, homogenized by ultrasound, and 0.6 mL of 6 mol / L acetic acid solution was added; The reaction solution was subjected to three freeze-thaw cycles for degassing and then placed in an oil bath at 120°C for 72 h; (2) The product of the oil bath reaction was washed with N,N-dimethylformamide, and the precipitate obtained by washing was soaked in 10 mL of tetrahydrofuran. After 12 hours, the precipitate was centrifuged and vacuum dried to obtain yellow powder COF BTH-DVa Material; (3) 100 mg COF BTH-DVa The material and 25 mg of azobisisobutyronitrile (AIBN) were transferred to a clean and dry 25 mL Shrek tube, and then 4 mL of 1,2-ethanedithiol was added. The reaction was stirred at 80 ° C for 48 h in a nitrogen atmosphere, and then the product of the stirred reaction was washed with acetone. The precipitate obtained by washing was vacuum dried to obtain SH-COF BTH-DVa Material.

[0026] Example 2

[0027] A method for preparing a covalent organic framework material comprises the following steps: (1) First, 50 mg of 1,3,5-benzenetricarboxylic acid hydrazide (BTH) and 56 mg of 2,5-divinyl-1,4-benzenedicarbaldehyde (DVa) were dissolved in 6 mL of a mixed solution of 1,4-dioxane and mesitylene, and dissolved by ultrasonication; The volume ratio of 1,4-dioxane to mesitylene is 1:1; The two solutions were then transferred to a Shrek tube, homogenized by ultrasound, and 0.6 mL of 6 mol / L acetic acid solution was added; The reaction solution was subjected to three freeze-thaw cycles for degassing and then placed in an oil bath at 120°C for 72 h; (2) The product of the oil bath reaction was washed with N,N-dimethylformamide, and the precipitate obtained by washing was soaked in 10 mL of tetrahydrofuran. After 12 hours, the precipitate was centrifuged and vacuum dried to obtain yellow powder COF BTH-DVa Material; (3) 100 mg COF BTH-DVa The material and 25 mg of azobisisobutyronitrile (AIBN) were transferred to a clean and dry 50 mL Shrek tube, and then 10 mL of 1,2-ethanedithiol was added. The reaction was stirred at 80 ° C for 48 h in a nitrogen atmosphere, and then the product of the stirred reaction was washed with acetone. The precipitate obtained by washing was vacuum dried to obtain SH-COF BTH-DVa Material.

[0028] Application Example 1

[0029] 10 mg of SH-COF prepared in Example 1 was added BTH-DVa The material was added to contain 200 mg / L Pb 2+The solution was stirred for 12 h to allow the adsorption to reach equilibrium.

[0030] Test Example 1

[0031] The SH-COF obtained in Example 1 BTH-DVa The morphology of the material was characterized, and the scanning electron microscopy image showed that SH-COF BTH-DVa It is a tubular structure material with thin strips growing evenly on the surface (such as Figure 1 as shown).

[0032] Analysis example 1 Fourier infrared curve diagram (such as Figure 2 The characteristic peak of the aldehyde group of 2,5-divinyl-1,4-benzenedicarboxylic acid (DVa) (C=O, 1685 cm -1 ) and the amino characteristic peaks of 1,3,5-benzenetricarboxylic acid hydrazide (BTH) (NH, 3298 cm -1 ) in COF BTH-DVa The COF BTH-DVa At 1659cm -1 There is an obvious -C=N- characteristic peak at the bottom, indicating that DVa and BTH have successfully undergone amine-aldehyde condensation reaction to generate COF BTH-DVa ; In addition, SH-COF BTH-DVa In keeping COF BTH-DVa At the same time as the characteristic peak at 2348cm -1 The characteristic peak of SH appeared at the BTH-DVa surface.

[0033] Figure 3 and Figure 4 Revealing SH-COF BTH-DVa and COF BTH-DVa Pb 2+ The adsorption process of Pb 2+ It belongs to the surface monolayer adsorption, and SH-COF BTH-DVa and COF BTH-DVa Pb 2+ The maximum adsorption capacities of SH-COF were 1474 mg / g and 910 mg / g, respectively. BTH-DVa The synergistic effect of multiple adsorption sites of -NN- and -SH in COFs can effectively enhance the adsorption of Pb 2+ adsorption capacity.

[0034] Figure 5 and Figure 6 The results showed that SH-COF BTH-DVa and COF BTH-DVaPb 2+ The adsorption conforms to the second-order kinetics, which proves that the adsorption process belongs to chemical adsorption.

[0035] The above embodiments are merely preferred implementations of the present invention. Any simple modification, amendment and substitution of the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a covalent organic framework material, characterized in that: The following steps are involved: (1) 1,3,5-benzenetricarboxylic acid hydrazide and 2,5-divinyl-1,4-benzenedicarbaldehyde are dispersed in a mixed solution of 1,4-dioxane and mesitylene, respectively, and dissolved by ultrasonication; Subsequently, the two solutions were transferred to a test tube, homogenized by ultrasound, and then the acetic acid solution was added; After degassing through several freeze-thaw cycles, the test tube was placed in an oil bath at 120°C to 125°C for reaction; (2) The product of the oil bath reaction was washed with N,N-dimethylformamide, the precipitate obtained by washing was soaked in tetrahydrofuran, and then vacuum dried to obtain COF BTH-DVa Material; (3) COF BTH-DVa The material and azobisisobutyronitrile were transferred to a clean test tube, and then 1,2-ethanedithiol was added. The reaction was stirred at 80°C to 85°C in an atmosphere of nitrogen protection. The product of the stirred reaction was then washed with acetone, and the precipitate obtained by washing was vacuum dried to obtain SH-COF BTH-DVa Material.

2. The method for preparing a covalent organic framework material according to claim 1, characterized in that: In step (1), the mass ratio of 1,3,5-benzenetricarboxylic acid hydrazide to 2,5-divinyl-1,4-benzenedicarbaldehyde is 25-26:27-28, and the mass volume ratio of the mixed solution of 1,3,5-benzenetricarboxylic acid hydrazide to 1,4-dioxane and mesitylene is 42g-43g:1L.

3. The method for preparing a covalent organic framework material according to claim 2, characterized in that: The volume ratio of 1,4-dioxane to mesitylene is 1:

1.

4. The method for preparing a covalent organic framework material according to claim 1, characterized in that: In step (1), the mass volume ratio of 1,3,5-benzenetricarboxylic acid hydrazide to the acetic acid solution is 42 g to 43 g:1 L, and the concentration of the acetic acid solution is 6 mol / L.

5. The method for preparing a covalent organic framework material according to claim 1, characterized in that: In step (1), the oil bath reaction time is 72 h to 75 h.

6. The method for preparing a covalent organic framework material according to claim 1, characterized in that: In step (2), the soaking time in tetrahydrofuran is 8 h to 12 h.

7. The method for preparing a covalent organic framework material according to claim 1, characterized in that: Step (3), COF BTH-DVa The mass ratio of the material to azobisisobutyronitrile is 4:1, COF BTH-DVa The mass volume ratio of the material to 1,2-ethanedithiol is 25g:1L.

8. The method for preparing a covalent organic framework material according to claim 1, characterized in that: In step (3), the stirring reaction time is 48 h to 50 h.

9. A covalent organic framework material prepared by the preparation method according to any one of claims 1 to 8, wherein the covalent organic framework material is SH-COF BTH-DVa Material.

10. The use of the covalent organic framework material according to claim 9 in the adsorption and removal of heavy metal ions, characterized in that: Pb in aqueous solution 2+ adsorption removal.

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