阅读说明：本技术 一种超疏水金属有机骨架材料及其制备方法与应用 (Super-hydrophobic metal organic framework material and preparation method and application thereof ) 是由 李万斌 容斯毅 苏鹏程 于 2021-08-09 设计创作，主要内容包括：本发明属于新型功能材料技术领域,公开了一种超疏水金属有机骨架材料及其制备方法与应用。所述方法按如下步骤进行：将疏水性微孔聚合物溶解在溶剂中,得到微孔聚合物溶液,随后将金属有机骨架颗粒,加入上述微孔聚合物溶液中,获得具备疏水微孔聚合物涂层的超疏水金属有机骨架材料。本发明通过简单高效的涂覆方法,在金属有机骨架材料表面构建疏水性涂层,解决金属有机骨架材料水稳定性差的问题。其中超薄的微孔聚合物涂层,不仅显著提高金属有机骨架材料的疏水性能,同时其多孔特性能够维持金属有机骨架材料原有的孔道结构及比表面积。本发明方法具有广泛的通用性,可以适用于多种金属有机骨架材料,具有很好的应用价值和前景。(The invention belongs to the technical field of novel functional materials, and discloses a super-hydrophobic metal organic framework material, and a preparation method and application thereof. The method comprises the following steps: dissolving hydrophobic microporous polymer in a solvent to obtain a microporous polymer solution, and then adding metal organic framework particles into the microporous polymer solution to obtain the super-hydrophobic metal organic framework material with the hydrophobic microporous polymer coating. According to the invention, the hydrophobic coating is constructed on the surface of the metal organic framework material by a simple and efficient coating method, so that the problem of poor water stability of the metal organic framework material is solved. The ultra-thin microporous polymer coating not only obviously improves the hydrophobic performance of the metal organic framework material, but also has the porous characteristic capable of maintaining the original pore structure and specific surface area of the metal organic framework material. The method has wide universality, can be suitable for various metal organic framework materials, and has good application value and prospect.)

1. A preparation method of a super-hydrophobic metal organic framework material is characterized by comprising the following steps:

(1) preparation of hydrophobic microporous polymer: mixing the monomer A, the monomer B, potassium carbonate and an organic solvent, and then carrying out heating reaction to obtain a hydrophobic microporous polymer after the reaction is finished;

(2) preparing a metal organic framework material: uniformly mixing metal salt, an organic ligand and a solvent to obtain a synthetic solution, then carrying out heating reaction under a closed condition, and obtaining metal organic framework particles after the reaction is finished;

(3) constructing a super-hydrophobic metal organic framework material: dissolving the hydrophobic microporous polymer synthesized in the step (1) in a solvent to obtain a microporous polymer solution, adding the metal organic framework particles prepared in the step (2) into the microporous polymer solution, stirring to obtain a metal organic framework/microporous polymer mixed solution, separating the mixed particles, and drying to obtain the super-hydrophobic metal organic framework material with the hydrophobic microporous polymer coating;

the monomer A in the step (1) is at least one of 5,5 ', 6, 6' -tetrahydroxy-3, 3,3 ', 3' -tetramethyl-1, 1 '-helical bisindane, 2', 3,3 '-tetrahydroxy-1, 1' -binaphthyl and 1,2,4, 5-tetrahydroxy benzene; the monomer B in the step (1) is at least one of tetrafluoroterephthalonitrile, decafluorobiphenyl and decafluorobiphenyl ketone.

2. The method of claim 1, wherein: the mass ratio of the monomer A to the monomer B in the step (1) is 1: 0.5 to 5.

3. The method of claim 1, wherein: the organic solvent in the step (1) is at least one of N-methyl pyrrolidone, N-N dimethylformamide, N-dimethylacetamide, N-diethylformamide and toluene;

the ratio of the potassium carbonate to the organic solvent in the step (1) is 0.01-10 g/mL.

4. The method of claim 1, wherein: the metal element in the metal salt in the step (2) is at least one of V, Zn, Ti, Cr, Cu, Co, Fe, Ni, Mg, Cd, Sr, Zr, Nb, Mo, Ba, Mg, Mn, Al and Gd; the metal salt is at least one of nitrate, chloride, sulfate and acetate of metal.

5. The method of claim 1, wherein: the organic ligand in the step (2) is at least one of trimesic acid, phthalic acid and 2-methylimidazole; the solvent in the step (2) is at least one of methanol, ethanol, propanol, isopropanol, tert-butanol, ethylene glycol, glycerol, pyrrolidone, N-N dimethylformamide, N-dimethylacetamide and N, N-diethylformamide.

6. The method of claim 1, wherein: the mass ratio of the metal salt to the organic ligand in the step (2) is 1: 0.5 to 5; the mass ratio of the metal salt to the solvent in the step (2) is 1: 50 to 600.

7. The method of claim 1, wherein: the solvent in the step (3) is at least one of dichloromethane, trichloromethane and tetrahydrofuran; the concentration of the microporous polymer solution is 0.01-10 wt%.

8. The method of claim 1, wherein: the heating reaction in the step (1) is stirring for 10-60 min at 100-200 ℃; the heating reaction in the step (2) is heat treatment for 5-48 h at 100-220 ℃; the stirring time in the step (3) is 1-10 h.

9. A superhydrophobic metal organic framework material prepared by the method of any one of claims 1-8.

10. The use of the superhydrophobic metal-organic framework material of claim 9 in gas storage, molecular separation, catalysis, sensing.

Technical Field

The invention belongs to the technical field of novel functional materials, and mainly provides a super-hydrophobic metal organic framework material, and a preparation method and application thereof.

Background

In recent years, metal organic framework materials, which are porous crystalline materials formed by coordination of metal ions or metal clusters and organic linkers, exhibit various characteristics such as a simple synthesis method, a large specific surface area, a unique porous structure, chemical diversity, and the like, and are widely used for gas storage, molecular separation, catalysis, energy storage, biomedicine, and the like. The function and application of the metal organic framework material are closely related to the inherent physical and chemical properties of the metal organic framework material. Most metal organic framework materials face the bottlenecks of water sensitivity, poor acid and alkali resistance and poor processability, such as CuBTC, MOF-5, MIL-53 and the like, when the metal organic framework materials are in a humid environment or exposed to air for a long time, coordination bonds of metal and organic connectors are easy to hydrolyze, so that the crystal structure is broken down, the specific surface area is reduced, the functionality is weakened, and the practical application of the metal organic framework materials is greatly limited. Therefore, the development of the metal organic framework material with high stability has great practical application value and significance.

To date, researchers have developed a variety of strategies for improving the water stability of metal-organic framework materials, mainly (1) using high-valent metal cations or hydrophobic ligands to form more powerful metal coordination bonds or to construct hydrophobic systems, but the search for suitable metal ions and ligands takes a lot of time. (Yuan et al, adv.mater.,2018,30, 1704303; Furukawa et al, J.am.chem.Soc.2014,136,4369-4381.) (2) introduction of a hydrophobic functional group, which reacts with an active site in the molecular structure, into the metal organic framework material to enhance hydrophobicity. However, it is difficult for researchers to obtain suitable hydrophobic functional groups to react with ligands or active sites, and the inherent porosity and physicochemical properties of metal organic framework materials are changed while the functional groups are introduced. (Sun et al, Angew. chem. int.Ed.,2019,58, 7405; Nguyen at al, J.am. chem.Soc.,2010,132,4560.) (3) constructing a surface hydrophobic protective layer, which improves the water stability by depositing hydrophobic molecules or polymers on the surface of the metal-organic framework material. However, non-porous hydrophobic coatings can reduce the specific surface area and surface mass transfer rate of the metal-organic framework material. In conclusion, (Carn-S nchez et al, adv. Mater.,2015,27, 869; Zhang et al, J.Am.chem.Soc.,2014,136,16978.) to find and develop a simple and general method for modifying metal-organic frameworks to improve the hydrophobicity and maintain the inherent porous property of the metal-organic framework material, the method has important significance for practical application.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention mainly aims to provide a preparation method of a super-hydrophobic metal organic framework material.

The invention also aims to provide the super-hydrophobic metal organic framework material prepared by the method.

The invention further aims to provide application of the super-hydrophobic metal organic framework material in gas storage, molecular separation, catalysis, sensing and the like.

The purpose of the invention is realized by the following scheme:

a preparation method of a super-hydrophobic metal organic framework material comprises the following steps:

(1) preparation of hydrophobic microporous polymer: mixing the monomer A, the monomer B, potassium carbonate and an organic solvent, and then carrying out heating reaction to obtain a hydrophobic microporous polymer after the reaction is finished;

(2) preparing a metal organic framework material: uniformly mixing metal salt, an organic ligand and a solvent to obtain a synthetic solution, then carrying out heating reaction under a closed condition, and obtaining metal organic framework particles after the reaction is finished;

(3) constructing a super-hydrophobic metal organic framework material: dissolving the hydrophobic microporous polymer synthesized in the step (1) in a solvent to obtain a microporous polymer solution, adding the metal organic framework particles prepared in the step (2) into the microporous polymer solution, stirring to obtain a metal organic framework/microporous polymer mixed solution, separating the mixed particles, and drying to obtain the super-hydrophobic metal organic framework material with the hydrophobic microporous polymer coating.

The monomer A in the step (1) is at least one of 5,5 ', 6, 6' -tetrahydroxy-3, 3,3 ', 3' -tetramethyl-1, 1 '-helical bisindane, 2', 3,3 '-tetrahydroxy-1, 1' -binaphthyl and 1,2,4, 5-tetrahydroxy benzene;

the monomer B in the step (1) is at least one of tetrafluoroterephthalonitrile, decafluorobiphenyl and decafluorobiphenyl ketone;

the organic solvent in the step (1) is at least one of N-methyl pyrrolidone, N-N dimethylformamide, N-dimethylacetamide, N-diethylformamide and toluene;

the ratio of the potassium carbonate to the organic solvent in the step (1) is 0.01-10 g/mL, preferably 0.1-1 g/mL;

the mass ratio of the monomer A to the monomer B in the step (1) is 1: 0.5 to 5, preferably 1: 1-2;

the heating reaction in the step (1) is stirring for 10-60 min at 100-200 ℃. Preferably, the heating reaction is performed under a nitrogen atmosphere.

And (2) after the heating reaction in the step (1) is finished, a purification step is also included, specifically, the obtained product is added into methanol, then water and acetone are used for stirring and washing, and finally vacuum drying is carried out for 24-72 h at the temperature of 80-150 ℃.

The metal element in the metal salt in the step (2) is at least one of V, Zn, Ti, Cr, Cu, Co, Fe, Ni, Mg, Cd, Sr, Zr, Nb, Mo, Ba, Mg, Mn, Al and Gd; preferably, the metal element in the metal salt is at least one of Zn, Al, Cu, Cr and Zr; the metal salt is at least one of nitrate, chloride, sulfate and acetate of metal; more preferably, the metal salt is particularly preferably at least one of zinc nitrate, copper nitrate, zirconium chloride, chromium nitrate and aluminum nitrate.

The organic ligand in the step (2) is at least one of trimesic acid, phthalic acid and 2-methylimidazole;

the solvent in the step (2) is at least one of methanol, ethanol, propanol, isopropanol, tert-butanol, ethylene glycol, glycerol, pyrrolidone, N-N dimethylformamide, N-dimethylacetamide and N, N-diethylformamide;

the mass ratio of the metal salt to the organic ligand in the step (2) is 1: 0.5 to 5, preferably 1: 1-2;

the mass ratio of the metal salt to the solvent in the step (2) is 1: 50-600, preferably 1: 100-300 parts;

the heating reaction in the step (2) is heat treatment for 5-48 hours at 100-220 ℃.

Preferably, after the heating reaction in the step (2) is completed, the method further comprises a purification step, wherein the synthesized powder is washed by a solvent and is dried in vacuum at 50-100 ℃ for 6-24 hours.

The solvent in the step (3) is at least one of dichloromethane, trichloromethane and tetrahydrofuran; the concentration of the microporous polymer solution is 0.01-10 wt%, preferably 0.1-2 wt%;

the stirring time in the step (3) is 1-10 h.

Preferably, the operation of step (3) is carried out at room temperature.

A super-hydrophobic metal organic framework material is prepared by the method.

The super-hydrophobic metal organic framework material is applied to gas storage, molecular separation, catalysis, sensing and the like.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) a hydrophobic coating is constructed on the surface of the metal organic framework material by a simple and efficient coating method, so that the problem of poor water stability of the metal organic framework material is solved.

(2) The ultra-thin microporous polymer coating not only obviously improves the hydrophobic performance of the metal organic framework material, but also has the porous characteristic capable of maintaining the original pore structure and specific surface area of the metal organic framework material.

(3) The method has wide universality, can be suitable for various metal organic framework materials, and has good application value and prospect.

Drawings

FIG. 1 is a contact angle diagram of a superhydrophobic CuBTC/PIM-1 composite material prepared in example 1 of the invention and CuBTC in a comparative example.

FIG. 2 is an XRD pattern of the superhydrophobic CuBTC/PIM-1 composite material prepared in example 1 of the present invention and CuBTC and simulated CuBTC in comparative example.

FIG. 3 is an XPS plot of the superhydrophobic CuBTC/PIM-1 composite material prepared in inventive example 1 and CuBTC in a comparative example.

FIG. 4 is a TEM image of a superhydrophobic CuBTC/PIM-1 composite material prepared in example 1 of the present invention;

FIG. 5 is a drawing showing nitrogen adsorption-desorption of the superhydrophobic CuBTC/PIM-1 composite material prepared in example 1 of the present invention and CuBTC in comparative example before and after water treatment.

FIG. 6 is an electron photograph and SEM image of a superhydrophobic CuBTC/PIM-1 composite material prepared in example 1 of the invention and CuBTC in a comparative example after water treatment.

FIG. 7 is an XRD pattern of CuBTC after water treatment in a superhydrophobic CuBTC/PIM-1 composite material prepared in example 1 of the present invention and in a comparative example.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the embodiments of the present invention are not limited thereto. The room temperature and the unspecified temperature are 20-35 ℃.

The reagents used in the examples are commercially available without specific reference.

Example 1

The hydrophobic microporous polymer is PIM-1, the metal organic framework is CuBTC, and the synthesized super-hydrophobic metal organic framework is CuBTC/PIM-1.

The preparation method comprises the following steps:

(1) synthesis of hydrophobic microporous polymer: using a high temperature synthesis method, 5 ', 6,6 ' -tetrahydroxy-3, 3,3 ', 3 ' -tetramethyl-1, 1 ' -spirobiindane (3.404g), tetrafluoroterephthalonitrile (2.001g) and potassium carbonate (3.414g) were added to a three-necked flask, and after nitrogen was introduced for 30min, N-methylpyrrolidone (20mL) and toluene (10mL) were added, and then the mixture was transferred to a 160 ℃ oil bath and stirred for 40 min. And after the reaction is finished, pouring the obtained viscous liquid into methanol, stirring and washing the viscous liquid by using deionized water and acetone, and finally drying the viscous liquid in vacuum at 120 ℃ for 48 hours to obtain the hydrophobic microporous polymer.

(2) Synthesis of metal organic framework (CuBTC): adding copper nitrate (4.154g) into deionized water (30mL) by adopting a hydrothermal synthesis method commonly used for metal organic frameworks, and stirring for 10min at room temperature; adding trimesic acid (2.0g) into N, N-dimethylformamide (30mL) and ethanol (30mL), and stirring at room temperature for 10 min; and then stirring and mixing the two clear solutions uniformly, transferring the mixture into a stainless steel autoclave lined with polytetrafluoroethylene, putting the stainless steel autoclave into an oven to perform heat treatment for 10 hours at 100 ℃, cooling the reaction product to room temperature after the reaction is finished, and stirring and washing the obtained powder by using N, N-dimethylformamide and methanol. Finally, vacuum drying is carried out at 80 ℃ for 12h to obtain the metal organic framework CuBTC (figure 1 is a contact angle diagram, figure 2 is an XRD diagram, figure 3 is an XPS diagram, and figure 5 is a nitrogen adsorption-desorption diagram) for later use.

(3) Preparation of super-hydrophobic CuBTC/PIM-1: adding the microporous polymer PIM-1(0.015g) synthesized in the step (1) into trichloromethane (10mL), stirring at room temperature for 20min to dissolve the microporous polymer PIM-1, then adding the metal organic framework CuBTC (0.5g) obtained in the step (2) into the microporous polymer solution, stirring at room temperature for 5h, uniformly coating, performing centrifugal separation to obtain composite particles, and performing vacuum drying at 80 ℃ for 12h to obtain the superhydrophobic CuBTC/PIM-1 (FIG. 1 is a contact angle diagram, FIG. 2 is an XRD diagram, FIG. 3 is an XPS diagram, FIG. 4 is a TEM diagram, and FIG. 5 is a nitrogen adsorption-desorption diagram).

As shown in fig. 1, the CuBTC/PIM-1 material exhibits its superhydrophobicity compared to CuBTC; as shown in the XRD spectrum of fig. 2, the XRD patterns of the prepared metal-organic framework, cuptc, and cuptc/PIM-1 material are similar to the simulated XRD pattern, which indicates that the metal-organic framework, cuptc, can be successfully prepared under the experimental conditions, and simultaneously, the crystal structure of the metal-organic framework, cuptc, remains unchanged after the microporous polymer coating is performed; FIG. 3 is an XPS plot showing the appearance of a new C-O-C peak for the superhydrophobic CuBTC/PIM-1 material compared to CuBTC, illustrating the successful preparation of CuBTC/PIM-1; for the TEM of fig. 4, an ultra-thin uniform hydrophobic polymer layer on the surface of the CuBTC can be obtained by a simple coating process. Meanwhile, a nitrogen adsorption-desorption experiment is carried out on the CuBTC/PIM-1 material, and the experimental result is shown in figure 5, which shows that the original pore structure and specific surface area of the CuBTC can still be maintained after coating modification. Finally, the crystal structure and internal pore size structure of the CuBTC and CuBTC/PIM-1 materials remained unchanged from the experimental results shown in FIGS. 5, 6 and 7 after three days of aqueous environmental treatment.

Example 2

The hydrophobic microporous polymer is PIM-1, and the metal organic framework is UiO-66-NH₂The synthesized super-hydrophobic metal organic framework is UiO-66-NH₂/PIM-1。

The preparation method comprises the following steps:

(1) synthesis of hydrophobic microporous polymer: using a high temperature synthesis method, 5 ', 6,6 ' -tetrahydroxy-3, 3,3 ', 3 ' -tetramethyl-1, 1 ' -spirobiindane (5.106g), tetrafluoroterephthalonitrile (3.002g) and potassium carbonate (5.121g) were added to a three-necked flask, and after introducing nitrogen gas for 40min, N-methylpyrrolidone (30mL) and toluene (15mL) were added, and then the mixture was transferred to a 150 ℃ oil bath and stirred for 40 min. And after the reaction is finished, pouring the obtained viscous liquid into methanol, stirring and washing the viscous liquid by using deionized water and acetone, and finally drying the viscous liquid in vacuum at 110 ℃ for 36 hours to obtain the hydrophobic microporous polymer.

(2) Metal organic framework UiO-66-NH₂The synthesis of (2): respectively weighing zirconium chloride (0.48g) and 2-aminoterephthalic acid (0.372g) by adopting a hydrothermal synthesis method commonly used for a metal organic framework, then adding N, N-dimethylformamide (40mL) and deionized water (0.19mL) to stir at room temperature for 15min, then transferring the solution into a stainless steel autoclave lined with polytetrafluoroethylene, carrying out thermal reaction at 120 ℃ for crystallization for 24h, cooling a reaction system to room temperature, obtaining powder by centrifugation, washing the powder with N, N-dimethylformamide and methanol respectively, and finally, carrying out vacuum drying on the powder at 85 ℃ for 24h to obtain the metal organic framework UiO-66-NH₂And then standby.

(3) Superhydrophobic UiO-66-NH₂Preparation of PIM-1: adding the microporous polymer PIM-1(0.023g) synthesized in the step (1) into trichloromethane (15mL), stirring at room temperature for 30min to dissolve the microporous polymer PIM-1, and then dissolving the metal organic framework UiO-66-NH obtained in the step (2)₂(0.75g) was added to the above microporous polymer solution, stirred at room temperature for 6 hours, and uniformly appliedThen, composite particles are obtained through centrifugal separation, and the super-hydrophobic UiO-66-NH can be obtained through vacuum drying for 12 hours at the temperature of 75 DEG C₂/PIM-1。

Example 3

The hydrophobic microporous polymer is PIM-1, the metal organic framework is MIL-101, and the synthesized super-hydrophobic metal organic framework is MIL-101/PIM-1.

The preparation method comprises the following steps:

(1) synthesis of hydrophobic microporous polymer: by a high-temperature synthesis method, 5 ', 6,6 ' -tetrahydroxy-3, 3,3 ', 3 ' -tetramethyl-1, 1 ' -spirobiindane (6.808g), tetrafluoroterephthalonitrile (4.002g) and potassium carbonate (8.28g) were added to a three-necked flask, nitrogen was introduced thereto for 50min, N-N dimethylformamide (40mL) was added, and the mixture was transferred to an oil bath at 170 ℃ and stirred for 40 min. And after the reaction is finished, pouring the obtained viscous liquid into methanol, stirring and washing the viscous liquid by using deionized water and acetone, and finally drying the viscous liquid in vacuum at 110 ℃ for 36 hours to obtain the hydrophobic microporous polymer.

(2) Synthesis of metal organic framework MIL-101: respectively weighing 1.2g of chromium nitrate and 0.5g of terephthalic acid in a conventional hydrothermal synthesis method for a metal organic framework, placing the chromium nitrate and the terephthalic acid in a teflon, adding 0.6mL of hydrofluoric acid solution with the concentration of 5mol/L and 15mL of deionized water, stirring for 15min by using a glass rod, placing the teflon in a stainless steel autoclave, heating for 8h at 220 ℃, cooling to room temperature after the reaction is finished, centrifuging to obtain powder, and stirring and washing the obtained powder by using N, N-dimethylformamide and methanol at 40 ℃. And finally, vacuum drying at 80 ℃ for 24h to obtain the metal organic framework MIL-101 for later use.

(3) Preparation of superhydrophobic MIL-101/PIM-1: adding the microporous polymer PIM-1(0.030g) synthesized in the step (1) into trichloromethane (20mL), stirring at room temperature for 40min to dissolve the microporous polymer PIM-1, then adding the metal organic framework MIL-101(1g) obtained in the step (2) into the microporous polymer solution, stirring at room temperature for 6h, uniformly coating, performing centrifugal separation to obtain composite particles, and performing vacuum drying at 80 ℃ for 12h to obtain the superhydrophobic MIL-101/PIM-1.

Example 4

The hydrophobic microporous polymer is PIM-2, the metal organic framework is MIL-53, and the synthesized super-hydrophobic metal organic framework is MIL-53/PIM-2.

The preparation method comprises the following steps:

(1) synthesis of hydrophobic microporous polymer: using a high temperature synthesis method, 5 ', 6,6 ' -tetrahydroxy-3, 3,3 ', 3 ' -tetramethyl-1, 1 ' -spirobiindane (3.404g), decafluorobiphenyl (3.341g), and potassium carbonate (4.14g) were added to a three-necked flask, nitrogen was introduced for 40min, N-methylpyrrolidone (20mL) and toluene (10mL) were added, and the mixture was transferred to a 160 ℃ oil bath and stirred for 40 min. And after the reaction is finished, pouring the obtained viscous liquid into methanol, stirring and washing the viscous liquid by using deionized water and acetone, and finally drying the viscous liquid in vacuum at 110 ℃ for 36 hours to obtain the hydrophobic microporous polymer.

(2) Synthesis of metal-organic framework MIL-53: adding aluminum nitrate (0.8g) and terephthalic acid (0.5g) into N, N-dimethylformamide (15mL) by adopting a hydrothermal synthesis method commonly used for metal organic frameworks, and stirring at room temperature for 20 min; and then transferring the solution into a stainless steel autoclave lined with polytetrafluoroethylene, putting the stainless steel autoclave into an oven, carrying out heat treatment at 120 ℃ for 24 hours, cooling the solution to room temperature after the reaction is finished, obtaining powder through centrifugation, and stirring and washing the obtained powder at 50 ℃ by using N, N-dimethylformamide and methanol. Finally, vacuum drying is carried out for 12h at the temperature of 80 ℃ to obtain the metal organic framework MIL-53 for later use.

(3) Preparation of super-hydrophobic MIL-53/PIM-2: adding the microporous polymer PIM-2(0.045g) synthesized in the step (1) into trichloromethane (30mL), stirring at room temperature for 60min to dissolve the microporous polymer PIM-2, then adding the metal organic framework MIL-53(1.5g) obtained in the step (2) into the microporous polymer solution, stirring at room temperature for 8h, uniformly coating, performing centrifugal separation to obtain composite particles, and performing vacuum drying at 80 ℃ for 24h to obtain the superhydrophobic MIL-53/PIM-2.

Example 5

The hydrophobic microporous polymer is PIM-6, the metal organic framework is ZiF-8, and the synthesized super-hydrophobic metal organic framework is ZiF-8/PIM-6.

The preparation method comprises the following steps:

(1) synthesis of hydrophobic microporous polymer: 1,2,4, 5-tetrahydroxybenzene (1.421g), decafluorobiphenyl (3.341g) and potassium carbonate (4.14g) were charged into a three-necked flask by a high-temperature synthesis method, and after introducing nitrogen gas for 40min, N-methylpyrrolidone (20mL) and toluene (10mL) were added, and then the mixture was transferred to an oil bath pan at 160 ℃ and stirred for 40 min. And after the reaction is finished, pouring the obtained viscous liquid into methanol, stirring and washing the viscous liquid by using deionized water and acetone, and finally drying the viscous liquid in vacuum at 110 ℃ for 36 hours to obtain the hydrophobic microporous polymer.

(2) Synthesis of Metal-organic framework ZiF-8: by adopting a hydrothermal synthesis method commonly used for metal organic frameworks, adding zinc nitrate (0.3g) and 2-methylimidazole (0.66g) into methanol (14mL) respectively, stirring at room temperature for 25min, and performing ultrasonic treatment for 30 min; and then transferring the solution into a stainless steel autoclave lined with polytetrafluoroethylene, putting the stainless steel autoclave into an oven, carrying out heat treatment for 12h at 150 ℃, cooling the solution to room temperature after the reaction is finished, centrifuging the solution to obtain powder, washing the obtained powder with methanol, and finally carrying out vacuum drying for 24h at 80 ℃ to obtain the metal organic framework ZiF-8 for later use.

(3) Preparation of super-hydrophobic ZiF-8/PIM-6: adding the microporous polymer PIM-6(0.050g) synthesized in the step (1) into trichloromethane (40mL), stirring at room temperature for 60min to dissolve the microporous polymer PIM-6, then adding the metal organic framework ZiF-8(2g) obtained in the step (2) into the microporous polymer solution, stirring at room temperature for 8h, uniformly coating, performing centrifugal separation to obtain composite particles, and performing vacuum drying at 80 ℃ for 24h to obtain the superhydrophobic ZiF-8/PIM-6.

Comparative example (original Metal organic framework, directly exposed to Water Environment without hydrophobic modification)

The metal organic framework material is CuBTC.

The preparation method comprises the following steps:

synthesis of metal organic framework (CuBTC): adding copper nitrate (4.154g) into deionized water (30mL) by adopting a hydrothermal synthesis method commonly used for metal organic frameworks, and stirring for 10min at room temperature; adding trimesic acid (2.0g) into N, N-dimethylformamide (30mL) and ethanol (30mL), and stirring at room temperature for 10 min; and then stirring and mixing the two clear solutions uniformly, transferring the mixture into a stainless steel autoclave lined with polytetrafluoroethylene, putting the stainless steel autoclave into an oven to perform heat treatment for 10 hours at 100 ℃, cooling the reaction product to room temperature after the reaction is finished, and stirring and washing the obtained powder by using N, N-dimethylformamide and methanol. And finally, carrying out vacuum drying at 80 ℃ for 12h to obtain the metal organic framework CuBTC.

As can be seen from the figure, the original CuBTC exhibited poor water stability after being exposed to an aqueous environment, in which both the crystal structure and the channel structure were destroyed (as shown in fig. 5, 6, and 7). In summary, the experimental results of example 1 and the comparative example prove that the super-hydrophobic microporous polymer coating layer constructed by the coating method can significantly improve the hydrophobic property of the metal organic framework material, enhance the water stability of the metal organic framework material, and maintain the inherent porous property of the metal organic framework material.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.