Covalent organic framework membrane material encapsulated with ion carrier as well as preparation method and application of covalent organic framework membrane material

Abstract

The invention discloses a covalent organic framework membrane material encapsulated with an ion carrier and a preparation method and application thereof. The covalent organic framework membrane material comprises a subject and an object, and the subject surrounds the object to encapsulate the object inside; the main body is a covalent organic framework membrane material which is obtained by carrying out condensation polymerization on an amino-functionalized monomer A and an aldehyde-group-functionalized monomer B and is shown as a formula (I) # imgabs0 #, the number x of amino groups of the monomer A is equal to the number y of aldehyde groups of the monomer B, and the sum of the functionality of the monomer A and the functionality of the monomer B is greater than or equal to 2. According to the invention, identification and separation of specific ions can be realized, and transmembrane transmission of the specific ions can be efficiently realized. The membrane preparation method is simple and stable, and the prepared membrane product can stably operate for a long time and maintain a constant separation ratio.

Description

Technical Field

[0001] The present invention relates to membrane separation technology, and specifically to a covalent organic framework membrane material encapsulating an ionophore, and a preparation method and application thereof. Background Art

[0002] Biological ion channels can significantly and selectively regulate the transmembrane movement of specific ions by binding specific ion affinity sites in channels with sub-nanometer pore diameters. Based on this mechanism, the design of biomimetic ion channels focuses on mimicking the pore characteristics of biological ion channels and their highly selective binding sites to achieve the recognition and separation of specific ions. However, there are still great challenges in precisely controlling the membrane pore size and constructing membrane materials with highly selective binding sites. Therefore, the development of economical and efficient ion-selective membrane materials remains an urgent problem to be solved.

[0003] Ionophores are a class of compounds that can selectively transport specific ions across membranes, and are widely used in the design of biomimetic selective ion channels, providing new ideas for the development of separation membrane materials.

[0004] Covalent organic framework (COF) materials have become an ideal choice for constructing efficient separation membranes due to their regular structures, uniform pore size distributions, high specific surface areas, good stabilities, and adjustable pore environments.

[0005] In order to improve the selectivity and transport efficiency of the membrane, some people have also proposed encapsulating ionophores into membrane materials to enhance the ion selectivity of the membrane, but the effect is still not ideal. And due to the complex structure of ionophores, it is often difficult to form continuous transport channels by directly post-modifying and incorporating them into membrane materials according to the current method. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a covalent organic framework membrane material encapsulating an ionophore, and a preparation method and application thereof. The preparation method can construct a transport channel, and the obtained covalent organic framework membrane material encapsulating an ionophore can efficiently achieve the transmembrane transport of specific ions.

[0007] To solve the above technical problems, the present invention first discloses a covalent organic framework membrane material encapsulating an ionophore, including a host and a guest, and the host encapsulates the guest by surrounding it; the host is a covalent organic framework membrane material, which is obtained by polycondensation of an amino-functionalized monomer A and an aldehyde-functionalized monomer B, as shown in formula (Ⅰ).

[0008]

[0009] In formula (I), the number of amino groups of monomer A × x = the number of aldehyde groups of B × y, and the sum of the functionality (reaction sites of the polycondensation reaction) of monomer A and monomer B is ≥ 2 to form an infinite framework material.

[0010] Furthermore, both monomer A and monomer B are selected from any one of formulas (1) to (14),

[0011]

[0012] When it is monomer A, R = -NH 2 , when it is monomer B, R = -CHO;

[0013] The ionophore is selected from one of 2,4-dinitrophenol, SA-3, Janus green, 18-crown-6, pillar[5]arene, ZIF-7, 8FC4P, cyclodextrin, calixarene, valinomycin or nystatin.

[0014] The structural formulas of the ionophores are as follows:

[0015]

[0016] Furthermore, the specific surface area of the bionic selective membrane is 200 - 750 m 2 / g, and the pore size is 0.5 - 1 nm.

[0017] The present invention also discloses a preparation method of a covalent organic framework membrane material encapsulated with an ionophore as described above. The interfacial polymerization method is adopted, and the specific steps include

[0018] (1) Dissolve monomer A and the ionophore in an acidic aqueous solution to form an aqueous phase solution; dissolve monomer B in an organic solvent to form an organic phase solution;

[0019] (2) Use a base film to separate the diffusion cell into two chambers;

[0020] (3) Place the aqueous phase and organic phase solutions obtained in step (1) into the two chambers in step (2) respectively. The organic phase solution is located on the front side (relatively smooth side) of the base film;

[0021] (4) Under the constant temperature condition of 25°C - 75°C, let the diffusion cell stand for 1 to 7 days to promote the formation of a COF (Covalent Organic Frameworks) membrane encapsulated with an ionophore on the front side of the base film;

[0022] (5) Remove the COF membrane together with the base film, and wash it successively with ethanol, methanol and water to remove the remaining monomers, acids and organic solvents, to obtain a covalent organic framework membrane material COF / base film encapsulated with an ionophore.

[0023] Further, in step (1), the molar dosage ratio of monomer A to monomer B is 0.5 - 5:1.

[0024] Further, in step (1), the acidic aqueous solution is acetic acid aqueous solution with a concentration of 1 - 6 mol / L, nitric acid aqueous solution with a concentration of 1 - 3 mol / L, or sulfuric acid aqueous solution with a concentration of 1 - 3 mol / L.

[0025] Further, in step (1), the organic solvent is one of dichloromethane, mesitylene, toluene, or ethyl acetate / mesitylene solution (the ethyl acetate / mesitylene solution is a solution of ethyl acetate and mesitylene mixed in any ratio).

[0026] Further, in step (1), the concentrations of monomer A and the ionophore in the aqueous solution phase, and the concentration of ionophore B in the organic solution phase are all 1 - 100 mmol / L.

[0027] Further, the base film used in step (2) is one of sheet-like polyacrylonitrile (PAN), polyethylene terephthalate (PET), polyethersulfone (PES), polycarbonate (PC), or anodic aluminum oxide (AAO).

[0028] The present invention also discloses the application of a covalent organic framework membrane material encapsulating an ionophore as described above or a covalent organic framework membrane material encapsulating an ionophore obtained by the preparation method as described above in ion separation.

[0029] Through the host-guest assembly strategy, the present invention enables the host material to form a porous matrix around the guest molecule through a self-assembly process, encapsulating the ionophore therein and constructing a transport channel to efficiently achieve the transmembrane transport of specific ions. That is, the present invention encapsulates ionophores with different functions into a three-dimensional covalent organic framework material with sub-nanometer pore size to obtain a covalent organic framework membrane material encapsulating an ionophore. Due to the diversity of ionophores, these membrane materials can achieve efficient selective separation of various ions according to different separation requirements, giving full play to the great potential of covalent organic framework membrane materials in the field of efficient separation.

[0030] The beneficial effects of the present invention are specifically as follows:

[0031] 1. High-selectivity separation: The present invention ingeniously designs a covalent organic framework membrane material encapsulating an ionophore, simulating the pore size characteristics and highly selective binding sites of biological ion channels, and can achieve the recognition and separation of specific ions.

[0032] 2. Adjustable membrane selectivity: The covalent organic framework membrane material encapsulated with ionophores can precisely adjust the selectivity of the membrane material by regulating the types of ionophores and the encapsulation density on the covalent organic framework membrane material (the encapsulation density is controlled by the concentration of ionophores during preparation), so as to efficiently achieve the transmembrane transport of specific ions.

[0033] 3. Stable membrane preparation method: The membrane preparation method provided by the present invention is simple and stable. The prepared membrane products can operate stably for a long time and maintain a constant separation ratio.

[0034] The above advantages make the present invention have potential broad application prospects in the field of membrane separation. Description of the Drawings

[0035] Figure 1 Schematic diagram of the interfacial polymerization method used in the present invention;

[0036] Figure 2a Surface scanning electron microscope image of COF-1 / PAN prepared in Example 1 of the present invention;

[0037] Figure 2b Cross-section scanning electron microscope image of the membrane of COF-1 / PAN prepared in Example 1 of the present invention;

[0038] Figure 3a Surface scanning electron microscope image of COF-2 / PES prepared in Example 2 of the present invention;

[0039] Figure 3b Cross-section scanning electron microscope image of the membrane of COF-2 / PES prepared in Example 2 of the present invention;

[0040] Figure 4a Surface scanning electron microscope image of COF-3 / PET prepared in Example 3 of the present invention;

[0041] Figure 4b Cross-section scanning electron microscope image of the membrane of COF-3 / PET prepared in Example 3 of the present invention;

[0042] Figure 5a Surface scanning electron microscope image of COF-4 / AAO prepared in Example 4 of the present invention;

[0043] Figure 5b Cross-section scanning electron microscope image of the membrane of COF-4 / AAO prepared in Example 4 of the present invention;

[0044] Figure 6a Surface scanning electron microscope image of COF-5 / PC prepared in Example 5 of the present invention;

[0045] Figure 6bSEM image of the cross-section of the COF-5 / PC membrane prepared in Example 5 of the present invention;

[0046] Figure 7-1 Nitrogen adsorption isotherm diagram of the COF-6 / PC membrane prepared in Example 6 of the present invention;

[0047] Figure 7-2 Pore size distribution diagram of the COF-6 / PC membrane prepared in Example 6 of the present invention. Detailed implementation manners

[0048] The present invention will be further explained below in conjunction with embodiments. The following embodiments are only used to illustrate the present invention, but not to limit the scope of implementation of the present invention.

[0049] In order to reflect the specific ion transport performance, different mixed salt systems are used in each embodiment for separation testing.

[0050] Example 1

[0051] Prepare a covalent organic framework membrane material COF-1 / PAN encapsulated with 2,4-dinitrophenol ionophore.

[0052]

[0053] Prepared by the liquid-liquid two-phase interfacial polymerization method. The preparation process includes the following steps:

[0054] (1) Take benzidine and the ionophore 2,4-dinitrophenol and dissolve them in 7 mL of 1 mol / L nitric acid aqueous solution to make the benzidine concentration 5 mmol / L and the ionophore 2,4-dinitrophenol concentration 10 mmol / L to obtain an aqueous solution; take phloroglucinol trialdehyde and dissolve it in 7 mL of ethyl acetate to make the phloroglucinol trialdehyde concentration 10 mmol / L to obtain an organic solution.

[0055] (2) Place the PAN membrane in the center of the diffusion cell, which divides the diffusion cell into two chambers.

[0056] (3) Place the aqueous solution and the oil phase solution obtained in step (1) in the two chambers of the diffusion cell respectively, where the organic solution is placed in the chamber facing the front (relatively smooth side) of the PAN membrane, and the aqueous solution is placed in the other chamber.

[0057] (4) React at a constant temperature of 25 °C for 1 day to promote the polymerization reaction at the interface between the two phases, and form a COF membrane encapsulated with the ionophore on the front of the PAN membrane.

[0058] (5) Remove the COF membrane from the base film PAN and wash it successively with ethanol, methanol, and water to remove residual monomers, nitric acid, and organic solvents, obtaining the covalent organic framework membrane material COF-1 / PAN encapsulated with ion carriers. The SEM results show that the thickness of the COF-1 / PAN membrane is 90 nm (for the SEM results of this membrane, see Figure 2a and Figure 2b ). The N 2 adsorption analysis results indicate that the specific surface area of the membrane is 221 m 2 / g and the pore size is 0.7 nm. The Na + / Mg 2+ separation ratio of the COF-1 / PAN bionic selective membrane in the ternary mixture system (0.01 M lithium chloride, potassium chloride, and sodium chloride) can reach 223.

[0059] Example 2

[0060] Prepare the covalent organic framework membrane material COF-2 / PES encapsulated with Janus green ion carriers.

[0061]

[0062] It is prepared by the liquid-liquid two-phase interfacial polymerization method. The preparation process includes the following steps:

[0063] (1) Dissolve tetrakis(4-aminophenyl)methane and the ion carrier Janus green in 7 mL of 6 mol / L acetic acid aqueous solution to make the concentration of tetrakis(4-aminophenyl)methane 16 mmol / L and the concentration of the ion carrier Janus green 6 mmol / L, obtaining an aqueous solution; dissolve 2,5-dimethoxybenzene-1,4-dicarbaldehyde in 7 mL of mesitylene to make the concentration of 2,5-dimethoxybenzene-1,4-dicarbaldehyde 5 mmol / L, obtaining an organic solution.

[0064] (2) Place the PES membrane in the center of the diffusion cell, which divides the diffusion cell into two chambers.

[0065] (3) Place the aqueous solution and the organic solution obtained in step (1) into the two chambers in step (2) respectively. The organic solution is placed in the chamber facing the front (relatively smooth surface) of the PES membrane, and the aqueous solution is placed in the other chamber.

[0066] (4) React at a constant temperature of 35 °C for 3 days while standing still to promote the polymerization reaction at the interface between the two phases and form a COF membrane encapsulated with ion carriers on the front of the PES.

[0067] (5) Remove the COF separation membrane from the base film PES and wash it successively with ethanol, methanol, and water to remove residual monomers, acetic acid, and organic solvents, obtaining the covalent organic framework membrane material COF-2 / PES encapsulated with ionophores. The SEM results show that the thickness of the membrane is 93 nm (for the SEM results of this membrane, see Figure 3a and Figure 3b ). The N 2 adsorption analysis results indicate that the specific surface area of the membrane is 744 m 2 / g and the pore size is 0.55 nm. The COF-2 / PES biomimetic selective membrane has a Na + / K + separation ratio of up to 136 in a five-component mixed system (0.05 M lithium chloride, potassium chloride, sodium chloride, magnesium chloride, sodium sulfate).

[0068] Example 3

[0069] Prepare the covalent organic framework membrane material COF-3 / PET encapsulated with the ionophore 8FC4P.

[0070]

[0071] It is prepared by the liquid-liquid two-phase interfacial polymerization method. The preparation process includes the following steps:

[0072] (1) Take 1,3,5-triaminobenzene and the ionophore 8FC4P and dissolve them in 7 mL of 1 mol / L nitric acid aqueous solution, so that the concentration of 1,3,5-triaminobenzene is 16 mmol / L and the concentration of the ionophore 8FC4P is 3 mmol / L, obtaining an aqueous solution; take tetrakis(4-formylphenyl)silane and dissolve it in 7 mL of dichloromethane, so that the concentration of tetrakis(4-formylphenyl)silane is 4 mmol / L, obtaining an organic solution.

[0073] (2) Place the PET membrane in the center of the diffusion cell, which divides the diffusion cell into two chambers.

[0074] (3) Place the aqueous solution and the organic solution obtained in step (1) into the two chambers in step (2) respectively. The organic solution is placed in the chamber facing the front (relatively smooth side) of the PET membrane, and the aqueous solution is placed in the other chamber.

[0075] (4) React at a constant temperature of 75 °C for 7 days to promote the polymerization reaction at the interface between the two phases and form a COF membrane encapsulated with ionophores on the front of the PET membrane.

[0076] (5) Remove the COF film from the base film PET and wash it successively with ethanol, methanol and water to remove residual monomers, nitric acid and organic solvents, obtaining the covalent organic framework membrane material COF-3 / PET encapsulated with ion carriers. The SEM results show that the thickness of the film is 99 nm (for the SEM results of this film, see Figure 4a and Figure 4b ). The N 2 adsorption analysis results show that the specific surface area of the film is 578 m 2 / g and the pore size is 0.82 nm. The Cl - / SO 4 2- separation ratio of the COF-3 / PET bionic selective membrane in the six-component mixed system (0.1 M lithium chloride, potassium chloride, sodium chloride, potassium sulfate, sodium sulfate, magnesium chloride) can reach 380.

[0077] Example 4

[0078] Prepare the covalent organic framework membrane material COF-4 / AAO encapsulated with valinomycin ion carriers.

[0079]

[0080] It is prepared by the liquid-liquid two-phase interfacial polymerization method. The preparation process includes the following steps:

[0081] (1) Take 1,4-phenylenediamine and valinomycin and dissolve them in 7 mL of 1 mol / L acetic acid aqueous solution to make the concentration of 1,4-phenylenediamine 14 mmol / L and the concentration of valinomycin 7 mmol / L, obtaining an aqueous solution; take tris(4-formylphenyl)amine and dissolve it in 7 mL of toluene to make the concentration of tris(4-formylphenyl)amine 12 mmol / L, obtaining an organic solution.

[0082] (2) Place the AAO membrane in the center of the diffusion cell, which divides the diffusion cell into two chambers.

[0083] (3) Place the aqueous solution and the organic solution obtained in step (1) into the two chambers in step (2) respectively. The organic solution is placed in the chamber facing the front (relatively smooth surface) of the AAO membrane, and the aqueous solution is placed in the other chamber.

[0084] (4) Let it stand and react at a constant temperature of 60 °C for 7 days to promote the polymerization reaction at the interface between the two phases and form a COF membrane encapsulated with ion carriers on the front of the AAO.

[0085] (5) Remove the COF membrane from the base film AAO and wash it successively with ethanol, methanol and water to remove residual monomers, acetic acid and organic solvents, obtaining the covalent organic framework membrane material COF-4 / AAO. The SEM results show that the thickness of the film is 96 nm (for the SEM results of this film, seeFigure 5a and Figure 5b ), N 2 The adsorption analysis results show that the specific surface area of the membrane is 360 m 2 / g, and the pore size is 0.92 nm. The COF-4 / AAO biomimetic selective membrane has a K + / Mg 2+ separation ratio of up to 269 in an eight-component mixed system (0.2 M lithium chloride, potassium chloride, sodium chloride, potassium sulfate, sodium sulfate, magnesium chloride, calcium chloride, potassium carbonate).

[0086] Example 5

[0087] Prepare a covalent organic framework membrane material COF-5 / PC encapsulated with nystatin ionophore.

[0088]

[0089] It is prepared by the liquid-liquid two-phase interfacial polymerization method. The preparation process includes the following steps:

[0090] (1) Dissolve 2,5-diamino-1,4-benzenediol and nystatin in 7 mL of 3 mol / L sulfuric acid aqueous solution to make the concentration of 2,5-diamino-1,4-benzenediol 10 mmol / L and the concentration of nystatin 6 mmol / L to obtain an aqueous solution; dissolve 3,3',6,6'-tetraformyl-9,9'-spirobifluorene in 7 mL of ethyl acetate / mesitylene to make the concentration of 3,3',6,6'-tetraformyl-9,9'-spirobifluorene 2 mmol / L to obtain an organic solution.

[0091] (2) Place the PC membrane in the center of the diffusion cell, which divides the diffusion cell into two chambers.

[0092] (3) Place the aqueous solution and the organic solution obtained in step (1) in the two chambers of step (2) respectively. The organic solution is placed in the chamber facing the front (relatively smooth side) of the PC membrane, and the aqueous solution is placed in the other chamber.

[0093] (4) Let it stand and react at a constant temperature of 50 °C for 4 days to promote the polymerization reaction at the interface between the two phases and form a COF membrane encapsulated with ionophore on the front of the PC membrane.

[0094] (5) Remove the COF membrane from the base membrane PC and wash it successively with ethanol, methanol and water to remove residual monomers, sulfuric acid and organic solvents to obtain a covalent organic framework membrane material COF-5 / PC encapsulated with ionophore. The SEM results show that the thickness of the membrane is 98 nm (for the SEM results of this membrane, see Figure 6a and Figure 6b ),N 2 The adsorption analysis results show that the specific surface area of the membrane is 546 m2 / g, with a pore size of 0.58 nm. The COF-5 / PC bionic selective membrane has a Li + / Mg 2+ separation ratio of up to 266.

[0095] Example 6

[0096] Prepare a covalent organic framework membrane material COF-6 / PC encapsulated with SA-3 ionophore.

[0097]

[0098] Prepared by the liquid-liquid two-phase interfacial polymerization method. The preparation process includes the following steps:

[0099] (1) Dissolve 2,5-diamino-1,4-benzenediol and SA-3 in 7 mL of 3 mol / L sulfuric acid aqueous solution, with the concentration of 2,5-diamino-1,4-benzenediol being 10 mmol / L and the concentration of SA-3 being 6 mmol / L to obtain an aqueous solution; dissolve 3,3',6,6'-tetraformyl-9,9'-spirobifluorene in 7 mL of ethyl acetate / mesitylene, with the concentration of 3,3',6,6'-tetraformyl-9,9'-spirobifluorene being 2 mmol / L to obtain an organic solution.

[0100] (2) Place the PC membrane in the center of the diffusion cell, which divides the diffusion cell into two chambers.

[0101] (3) Place the aqueous solution and the organic solution obtained in step (1) into the two chambers in step (2) respectively. The organic solution is placed in the chamber facing the front (relatively smooth surface) of the PC membrane, and the aqueous solution is placed in the other chamber.

[0102] (4) Let it stand and react at a constant temperature of 50 °C for 4 days to promote the polymerization reaction at the interface between the two phases, and form a COF membrane encapsulated with ionophore on the front of the PC membrane.

[0103] (5) Remove the COF membrane from the base membrane PC, and wash it successively with ethanol, methanol and water to remove residual monomers, sulfuric acid and organic solvents, to obtain a covalent organic framework membrane material COF-6 / PC encapsulated with ionophore. The SEM result shows that the thickness of the membrane is 98 nm, and the N 2 adsorption analysis result shows that the specific surface area of the membrane is 546 m 2 / g, with a pore size of 0.58 nm (see Figure 7-2 ). The Cl in the octa-component mixture system (0.25 M lithium chloride, potassium chloride, sodium chloride, potassium sulfate, sodium sulfate, magnesium chloride, calcium chloride, potassium carbonate) of the COF-6 / PC membrane- / SO 4 2- The separation ratio can reach 489.

[0104] Comparative Example 1

[0105] The cation exchange membrane CSE material produced by Japan's ASTOM Corporation was used to conduct separation performance tests under different mixed salt systems successively with reference to Examples 1, 2, 4, and 5. The results showed that for Na + / Mg 2+ 、Na + / K + 、K + / Mg 2+ 、Li + / Mg 2+ the separation ratios were 10.3, 0.7, 13.8, and 14.2 respectively.

[0106] Comparative Example 2

[0107] The anion exchange membrane ASE material produced by Japan's ASTOM Corporation was used to conduct separation performance tests under different mixed salt systems with reference to the operation in Example 3. The results showed that for Cl - / SO 4 2- the separation ratio was 15.6.

[0108] Comparison of separation ratio data:

[0109] Through the synergistic effect of the main material and the ion carrier, the present invention has successfully achieved the selective separation of different ions, and its separation effect on various ions is better than that of the ion exchange membrane materials produced by Japan's ASTOM Corporation. At the same time, we can precisely control the selectivity of the membrane material by adjusting the type and density of the ion carrier, so as to achieve the efficient transmembrane transport of specific ions. However, the anion and cation exchange membrane materials produced by Japan's ASTOM Corporation lack the ability to precisely regulate the separation effect of specific ions. Thus, it can be seen that the covalent organic framework membrane material encapsulating ion carriers of the present invention has significant advantages in achieving the efficient selective separation of multiple ions.

Claims

1. A covalent organic framework membrane material encapsulating an ion carrier, characterized in that: The invention comprises a main body and a guest, wherein the main body surrounds the guest and encapsulates the guest inside; the main body is a covalent organic framework membrane material, which is obtained by polycondensation reaction of an amino-functionalized monomer A and an aldehyde-functionalized monomer B, as shown in formula (I), In formula (I), the number of amino groups in monomer A×x=the number of aldehyde groups in B×y, and the sum of the functionalities of monomer A and monomer B is ≥2.

2. The covalent organic framework membrane material encapsulated with ion carriers according to claim 1, characterized in that: Monomer A and monomer B are selected from any one of formula (1) to formula (14), When it is monomer A, R = -NH2, when it is monomer B, R = -CHO; The ion carrier is selected from one of 2,4-dinitrophenol, SA-3, Janus green, 18-crown-6, pillar[5]arene, ZIF-7, 8FC4P, cyclodextrin, calixarene, valinomycin or nystatin.

3. The covalent organic framework membrane material encapsulated with ion carriers according to claim 1, characterized in that: The specific surface area of ​​the covalent organic framework membrane material encapsulating the ion carrier is 200 to 750 m 2 / g, and the pore size is 0.5~1nm.

4. A method for preparing a covalent organic framework membrane material encapsulating an ion carrier according to any one of claims 1 to 3, characterized in that: (1) dissolving monomer A and ion carrier in an acidic aqueous solution to form an aqueous phase solution; dissolving monomer B in an organic solvent to form an organic phase solution; (2) using a basement membrane to separate the diffusion cell into two chambers; (3) placing the aqueous phase and organic phase solutions obtained in step (1) in the two chambers of step (2) respectively, with the organic phase solution being located on the front side of the basement membrane; (4) leaving the diffusion cell at a constant temperature of 25° C. to 75° C. for 1 to 7 days to form a COF membrane encapsulating the ion carrier on the front side of the base membrane; (5) The COF membrane is removed together with the base membrane, and is washed with ethanol, methanol and water in sequence to obtain a covalent organic framework membrane material COF / base membrane encapsulating ion carriers.

5. The preparation method according to claim 4, characterized in that: In step (1), the molar ratio of monomer A to monomer B is 0.5 to 5:

1.

6. The preparation method according to claim 4, characterized in that: In step (1), the acidic aqueous solution is a 1-6 mol / L acetic acid aqueous solution, a 1-3 mol / L nitric acid aqueous solution or a 1-3 mol / L sulfuric acid aqueous solution.

7. The preparation method according to claim 4, characterized in that: In step (1), the organic solvent is one of dichloromethane, mesitylene, toluene or ethyl acetate / mesitylene solution.

8. The preparation method according to claim 4, characterized in that: In step (1), the concentrations of monomer A and ion carrier in the aqueous solution and the concentration of ion carrier B in the organic solution are both 1 to 100 mmol / L.

9. The preparation method according to claim 4, characterized in that: The base film used in step (2) is a thin sheet of polyacrylonitrile, polyethylene terephthalate, polyether sulfone, polycarbonate or anodized aluminum.

10. Use of a covalent organic framework membrane material encapsulating an ion carrier as claimed in any one of claims 1 to 3 or a covalent organic framework membrane material encapsulating an ion carrier obtained by the preparation method according to any one of claims 4 to 9 in ion separation.

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