Covalent organic framework pervaporation hybrid membrane based on combinatorial sequential regulation of interlayer structure and its preparation and application

Abstract

The present invention belongs to the technical field of pervaporation membrane preparation and application, and relates to a covalent organic framework pervaporation hybrid membrane with a combined sequentially regulated interlayer structure, and specifically relates to the preparation of the pervaporation membrane and its application in water / butanol separation. An aldehyde monomer solution is added to an amino monomer solution and allowed to stand for reaction; the aqueous phase is taken and dialyzed; the covalent organic framework nanosheet dispersion is diluted to obtain dispersion A; the polyelectrolyte aqueous solution is adjusted to obtain solution B; the metal ion dispersion is adjusted to obtain solution C. Dispersion A and solution C are uniform at room temperature, solution B is added, and the temperature is raised to react to obtain a casting solution. The casting solution is filtered onto a base membrane and vacuum dried to obtain a pervaporation membrane. At 70 o C, the separation flux of 10wt% / 90wt% water / butanol mixture is 7.52 g / (m 2 h), the separation factor reaches 13709.

Description

Technical Field

[0001] The present invention belongs to the technical field of pervaporation membrane preparation and application, and relates to a covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure, and particularly relates to the preparation of the pervaporation membrane and its application in water / butanol separation. Background Art

[0002] Butanol is a key industrial chemical, serving as both a solvent and a renewable biofuel. Butanol dehydration is crucial in the chemical industry. Compared to traditional distillation processes, membrane pervaporation (PV) technology has attracted widespread attention due to its higher efficiency, pollution-free operation, and low energy consumption. The selection and preparation of high-performance membrane materials are crucial for the application of PV technology. In recent years, ultrathin separation membranes fabricated from two-dimensional nanosheets, such as graphene oxide (GO), have been extensively studied, with their separation performance surpassing the performance bottlenecks of traditional polymer membrane materials. However, GO nanosheets are nearly non-porous, with tortuous mass transfer channels within the membrane, resulting in limited improvements in permeation flux. New two-dimensional (2D) COF nanosheets possess a high density of regular pores, a high degree of functionalization control, and excellent structural stability. Assembling them into membranes promises high flux and has become a key research topic in the water treatment field. However, the application of COF membranes in pervaporation processes presents significant challenges. Firstly, the large channel size of COF makes precise size separation difficult, limiting its application in small molecule separations. Secondly, COF nanosheets are difficult to directly assemble into membranes. Specifically, ionic COF nanosheets are difficult to assemble neatly due to strong repulsion between them, while non-ionic COF nanosheets aggregate due to π-π stacking. Due to these two reasons, the application of COF membranes in butanol dehydration is currently scarce, and their performance has been suboptimal. Therefore, it is necessary to develop novel COF membrane preparation methods to obtain COF pervaporation membranes with high flux and high separation factor, thereby achieving the production of high-purity butanol. Summary of the Invention

[0003] In response to the challenges faced by the above-mentioned COF membrane in the pervaporation process for preparing high-purity butanol, the present invention proposes a novel covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure and its application in water / butanol separation.

[0004] In order to achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0005] A method for preparing a covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure, wherein the pervaporation membrane comprises a substrate and a functional layer, and the steps are as follows:

[0006] (1) dissolving an aldehyde organic monomer in an organic solvent and mixing them uniformly to obtain an aldehyde monomer solution; dissolving an amino organic monomer in deionized water and mixing them uniformly to obtain an amino monomer solution; adding the aldehyde monomer solution to the amino monomer solution and allowing the mixture to react; after the reaction is completed, taking the aqueous phase and dialyzing it to obtain a covalent organic framework nanosheet dispersion.

[0007] (2) The covalent organic framework nanosheet dispersion was diluted and the pH was adjusted to neutral to obtain dispersion A; a polyelectrolyte aqueous solution was prepared and the pH was adjusted to neutral to obtain solution B; a metal ion dispersion was prepared and the pH was adjusted to neutral to obtain solution C.

[0008] (3) Dispersion A and solution C are mixed at room temperature and stirred evenly, then solution B is added, stirred and heated to react, and after the reaction is completed, it is naturally cooled to room temperature to obtain a casting solution.

[0009] (4) The casting solution is filtered onto the base membrane and vacuum dried to obtain a pervaporation membrane.

[0010] Preferably, the concentration of the aldehyde monomer solution in step (1) is 1-10 mmol / L; the amino monomer solution is a mixture of an amino organic monomer and an auxiliary agent, the molar concentrations of the amino organic monomer and the auxiliary agent are both 1-10 mmol / L, and the molar ratio of the aldehyde monomer to the amino monomer is 1:(1-3); the static reaction time is 4-6 days, and the dialysis treatment time is 2-4 days; the auxiliary agent is sodium carbonate or p-toluenesulfonic acid.

[0011] Preferably, the metal ion in step (2) is any one of sodium ion, potassium ion, magnesium ion, calcium ion, zinc ion, copper ion, aluminum ion, and iron ion; the covalent organic framework nanosheet is any one of TpPa-SO3H or TpEB, and the covalent organic framework nanosheet is prepared by interfacial polymerization; and the polyelectrolyte is any one of polyethyleneimine, sodium alginate, polyacrylic acid, and polyethyleneamine.

[0012] Preferably, in step (2), the concentration of the covalent organic framework dispersion in dispersion A is 0.01-0.03 mg / ml, the concentration of the polyelectrolyte solution in solution B is 0.01-0.03 mg / ml, the concentration of the metal ion in solution C is 3-4 mmol / L, and the volume ratio of dispersion A:solution B:solution C is (1-2):(2-3):(1-2).

[0013] Preferably, in step (3), the dispersion A and solution C are mixed and stirred at room temperature for 8-15 min, and after solution B is added, the reaction temperature is raised to 75-85° C., and the reaction time is 0.9-1.2 h.

[0014] The present invention proposes the use of a covalent organic framework pervaporation hybrid membrane with a combined sequentially regulated interlayer structure obtained by the above preparation method in water / butanol separation.

[0015] In the preparation method provided by the present invention, polyelectrolytes induce uniform film formation of covalent organic framework nanosheets through electrostatic interactions. Furthermore, polymer chains are fully mobilized and aggregated around the covalent organic framework, enhancing hydrophilicity and reducing channel size. Finally, the interaction between metal ions, the covalent organic framework, and the polyelectrolyte is utilized to control the order of their combination to form an optimal microscopic channel structure, thereby constructing a precise and efficient water molecule transport channel. The specific process involves preparing a dispersion / solution of the polyelectrolyte, metal ions, and covalent organic framework. After adjusting the pH, the polyelectrolyte solution and the covalent organic framework dispersion are mixed at room temperature. The metal ion solution is then added and heated with stirring to react, resulting in a mixed solution. The resulting mixed solution is then co-assembled onto the surface of a base membrane using vacuum-assisted filtration to prepare a covalent organic framework pervaporation hybrid membrane. The polyelectrolyte's abundant amino groups, metal ions, and sulfonic acid groups on the covalent organic framework all possess extremely high hydrophilicity. Furthermore, the hydrophilic chains cover the hydrophobic portions of the covalent organic framework, forming a highly hydrophilic surface of the hybrid membrane material. This synergistic effect with the hydrophobic covalent organic framework ultimately achieves selective adsorption and rapid transport of water molecules. The above effects can achieve a simultaneous improvement in the flux and separation factor of the pervaporation membrane.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are:

[0017] 1. The preparation method of the present invention is simple and controllable. The prepared covalent organic framework pervaporation hybrid membrane with controlled interlayer structure can be prepared at 70 o C, the permeation flux of the pervaporation separation of 10wt% / 90wt% water / butanol mixture was 7.52 kg / (m 2 h), the separation factor for butanol reaches 13709, which can effectively retain butanol molecules.

[0018] 2. The pervaporation membrane prepared by this invention exhibits excellent stability and is adaptable to high-temperature, high-concentration operating environments. Even after 360 hours of continuous monitoring, the pervaporation membrane performance remained stable. It can be used for pervaporation water / butanol separation and has broad application prospects in solvent separation and purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The XPS characterization of the pervaporation membrane obtained in Example 1 shows Zn 2+ Fine spectrum.

[0020] Figure 21 is a performance diagram of the pervaporation membrane obtained in Example 1 at different feed liquid temperatures (feed liquid concentration: 10 wt % water / butanol).

[0021] Figure 3 1 is a performance diagram of the pervaporation membrane obtained in Example 1 at different feed liquid concentrations (feed liquid temperature 70° C.). DETAILED DESCRIPTION

[0022] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below in conjunction with specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0024] Example 1

[0025] This embodiment provides a method for preparing a covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure.

[0026] Dissolve 0.1 mmol of trialdehyde phloroglucinol in 20 ml of n-octanoic acid and stir until uniformly mixed to obtain an aldehyde monomer solution. Dissolve 0.15 mmol of 2,5-diaminobenzenesulfonic acid and 0.15 mmol of sodium carbonate in 30 ml of water and stir until uniformly mixed to obtain an amino monomer solution. The aldehyde monomer solution was then poured into the amino monomer solution, sealed, and allowed to react at room temperature for 5 days. After the reaction, the organic layer was discarded, and the aqueous phase mixture was dialyzed using a dialysis bag (MW1000, Jelupu) for 3 days to obtain a dispersion of TpPa-SO3H nanosheets.

[0027] The concentration of the resulting TpPa-SO3H nanosheet dispersion was determined by drying a sample. The desired volume of TpPa-SO3H nanosheet dispersion was then calculated based on a final concentration of 0.02 mg / ml. The sample was then diluted to 5 ml with deionized water. A 10 ml 0.02 mg / mL aqueous solution of polyvinylamine (PEAm, Mw=70k) was prepared, followed by a 5 ml 3.1 mmol / L aqueous solution of zinc nitrate. The pH of each of these three solutions or dispersions was adjusted to 7 using either sodium hydroxide or hydrochloric acid (both at a concentration of 2 mol / L). After pH adjustment, the TpPa-SO3H nanosheet dispersion and the aqueous zinc nitrate solution were mixed and stirred at room temperature for 10 minutes. The aqueous polyvinylamine solution was then added and stirred until uniformly mixed. The mixture was then placed in an 80°C waterbath and stirred for 1 hour at a rate of 200-500 rpm. After the reaction, the mixture was cooled to room temperature to obtain a mixed solution.

[0028] The mixed solution obtained in the above steps was filtered onto a porous polyacrylonitrile-based membrane (circular flat ultrafiltration membrane, 4 cm in diameter, MWCO: 100 kDa, Shandong Lanjing Membrane Technology Engineering Co., Ltd., China) to prepare a functional layer. After the membrane surface was completely dried, it was vacuum-dried at room temperature for 2 h to obtain a covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure.

[0029] Since the TpPa-SO3H nanosheet dispersion was first mixed with the zinc nitrate aqueous solution, the covalent organic framework first 2+ The electrostatic interaction and cation-π interaction were formed. The pervaporation membrane prepared in this example was characterized by XPS. The results were as follows. Figure 1 ,according to Figure 1 Zn in XPS 2+ The fine peak spectrum shows that the Zn←O peak area in the covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure prepared in this embodiment is 58.42%, which is 34.59% of the Zn←O peak area in the membrane of comparative example 1. 2+ The cross-linking effect of the formation of the polyelectrolyte makes it form a tight arrangement before blending with the polyelectrolyte, which ultimately results in a compact and rich interlayer of polyelectrolyte and Zn 2+ The membrane is at 70 o C, the permeation flux of the pervaporation separation of 10wt% / 90wt% water / butanol mixture is 7.52kg / (m 2 h), the water / butanol separation factor was 13709. Under this condition, the pervaporation membrane performance remained stable after 360 hours of continuous monitoring.

[0030] Example 2

[0031] This embodiment is consistent with the embodiment 1 unless otherwise specified.

[0032] Dissolve 0.1 mmol of trialdehyde phloroglucinol in 100 ml of dichloromethane and stir until uniformly mixed to obtain an aldehyde monomer solution. Dissolve 0.3 mmol of ethidium bromide and 0.3 mmol of p-toluenesulfonic acid in 100 ml of water and stir until uniformly mixed to obtain an amino monomer solution. Pour the aldehyde monomer solution into the amino monomer solution, seal the container, and allow it to react at room temperature for 5 days. After the reaction, discard the organic layer and dialyze the aqueous mixture using a dialysis bag for 3 days to obtain a dispersion of TpEB nanosheets.

[0033] The concentration of the obtained TpEB nanosheet dispersion was determined by sampling and drying. The volume of TpEB nanosheet dispersion required was calculated based on a concentration of 0.023 mg / ml and diluted to 6 ml with deionized water. 13 ml of a 0.027 mg / mL sodium alginate aqueous solution was prepared, followed by 7 ml of a 3.3 mmol / L sodium nitrate aqueous solution. The pH of the three solutions or dispersions was adjusted to 7 using sodium hydroxide solution or hydrochloric acid solution, respectively, for later use. After pH adjustment, the TpEB nanosheet dispersion was first blended with an aqueous zinc nitrate solution and stirred at room temperature for 13 minutes. Subsequently, the sodium alginate (SA) aqueous solution was added and stirred until uniform. The mixture was then placed in an 80°C water bath and stirred for 1 hour at a stirring rate of 200-500 rpm. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a mixed solution.

[0034] The mixed solution obtained in the above steps was filtered onto a porous polyacrylonitrile-based membrane. After the membrane surface was completely dried, it was vacuum dried at room temperature for 2 hours to obtain a covalent organic framework pervaporation hybrid membrane with a combined sequentially regulated interlayer structure.

[0035] The pervaporation membrane prepared in this example was characterized by XPS. The Na←O peak area in the covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure prepared in this example was 60.01%, which was much larger than the Zn←O peak area of ​​34.59% in the membrane of Comparative Example 1. This also proves that the interaction between the nanosheets is strong, resulting in a compact and rich interlayer structure of polyelectrolytes and Na + The membrane has a channel structure and a permeation flux of 11.03 kg / (m 2 h), the water / butanol separation factor is 25563.

[0036] Example 3

[0037] This embodiment is consistent with the embodiment 1 unless otherwise specified.

[0038] Dissolve 0.2 mmol of trialdehyde phloroglucinol in 20 ml of n-octanoic acid and stir until uniformly mixed to obtain an aldehyde monomer solution. Dissolve 0.3 mmol of 2,5-diaminobenzenesulfonic acid and 0.3 mmol of sodium carbonate in 30 ml of water and stir until uniformly mixed to obtain an amino monomer solution. Pour the aldehyde monomer solution into the amino monomer solution, seal the container, and allow it to react at room temperature for four days. After the reaction, discard the organic layer and dialyze the aqueous mixture using a dialysis bag for four days to obtain a dispersion of TpPa-SO3H nanosheets.

[0039] The concentration of the resulting TpPa-SO3H nanosheet dispersion was determined by drying a sample. The desired volume of TpPa-SO3H nanosheet dispersion was then sampled at a concentration of 0.028 mg / ml and diluted to 9 ml with deionized water. 15 ml of a 0.025 mg / mL aqueous solution of polyvinylamine (PEAm, Mw=70k) was prepared, followed by 7 ml of a 3.6 mmol / L aqueous solution of sodium nitrate. The pH of each of these three solutions or dispersions was adjusted to 7 using sodium hydroxide or hydrochloric acid, respectively. After pH adjustment, the TpPa-SO3H nanosheet dispersion and the aqueous sodium nitrate solution were mixed and stirred at room temperature for 15 minutes. Then, the aqueous solution of polyethylenimine (PEI, Mw=10k) was added and stirred until uniform. The mixture was then placed in an 83°C waterbath and stirred for 1 hour at a rate of 200-500 rpm. After the reaction, the mixture was cooled to room temperature to obtain a mixed solution.

[0040] The mixed solution obtained in the above steps was filtered onto a porous polyacrylonitrile-based membrane. After the membrane surface was completely dried, it was vacuum dried at room temperature for 2 hours to obtain a covalent organic framework pervaporation hybrid membrane with a combined sequentially regulated interlayer structure.

[0041] The pervaporation membrane prepared in this example was characterized by XPS. The Na←O peak area in the covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure prepared in this example was 57.35%, which was larger than the Zn←O peak area of ​​34.59% in the membrane of Comparative Example 1. This indicates that the covalent organic framework first reacts with Na + Electrostatic interactions and cation-π interactions are formed. Before the addition of polyelectrolytes, the interaction between nanosheets is strong, resulting in a compact and rich interlayer of polyelectrolytes and Na + The membrane has a channel structure and a permeation flux of 7.78 kg / (m 2 h), the water / butanol separation factor is 12033.

[0042] Comparative Example 1

[0043] This comparative example differs from Example 1 in that, during the preparation of the casting solution, after adjusting the pH of each solution or dispersion to neutral, the polyvinylamine aqueous dispersion and the zinc nitrate aqueous solution were first blended and stirred at room temperature for 10 minutes. The mixture was then mixed with the diluted TpPa-SO3H nanosheet dispersion and heated at 80°C for 1 hour. All other conditions and preparation procedures remained the same as in Example 1.

[0044] The pervaporation membrane prepared in this comparative example was characterized by XPS. The results showed that the peak area of ​​Zn←O was 34.59%, and the peak area of ​​Zn←N was 65.41%. Compared with Example 123, the peak area of ​​Zn←O accounted for a smaller proportion, indicating that the polyelectrolyte first reacted with Zn 2+ The formation of coordination effect weakens the interaction between it and the covalent organic framework, resulting in a loose structure but rich in polyelectrolyte and Zn 2+ The channel structure of the membrane is 70 o C, the permeation flux of the pervaporation separation of 10wt% / 90wt% water / butanol mixture is 8.06kg / (m 2 h), the water / butanol separation factor is 7952.

[0045] Comparative Example 2

[0046] This comparative example differs from Example 1 in that, during the preparation of the casting solution, after adjusting the pH of each solution or dispersion to neutral, the polyvinylamine aqueous dispersion was first blended with the diluted TpPa-SO3H nanosheet dispersion and stirred at room temperature for 10 minutes. The mixture was then mixed with the zinc nitrate aqueous solution and heated to 80°C for 1 hour. All other conditions and preparation procedures remained the same as in Example 1.

[0047] The pervaporation membrane prepared in this comparative example was characterized by XPS. The results showed that the peak area of ​​Zn←O was 41.98%, and the peak area of ​​Zn←N was 58.02%. The polyelectrolyte first interacted with the covalent organic framework. 2+ It has a large hydration radius, which makes it difficult for it to enter the interior of the nanocomposite material. It only interacts with the organic framework and polyelectrolyte at the gap. Therefore, compared with Example 123 and Comparative Example 1, its Zn←O peak area is between the two, and finally a relatively compact channel structure with only polyelectrolyte between the layers is formed. The membrane is 70 o C, the permeation flux of the pervaporation separation of 10wt% / 90wt% water / butanol mixture is 6.08kg / (m 2 h), the water / butanol separation factor is 5407.

[0048] The results of Comparative Examples 1 and 2 show that the mixing of the polyelectrolyte solution, the metal ion solution and the covalent organic framework dispersion in different combinations has a significant effect on the microscopic interlayer structure and separation performance of the pervaporation membrane.

[0049] Comparative Example 3

[0050] This comparative example differs from Example 1 in that no metal ion solution was added to the casting solution. Instead, the polyvinylamine aqueous dispersion and the diluted TpPa-SO3H nanosheet dispersion were stirred and reacted at 80°C for 1 hour. All other conditions and preparation procedures remained the same as in Example 1.

[0051] XPS characterization revealed that no metal ions were detected in the polyelectrolyte-covalent organic framework membrane obtained in this comparative example. oC The permeation flux of the pervaporation separation of 10wt% / 90wt% water / butanol mixture is 4.12kg / (m 2 h), the water / butanol separation factor is 2573.

[0052] 1. Investigation of the stability of pervaporation membrane relative to temperature

[0053] The pervaporation membrane prepared in Example 1 was used to separate 10 wt% water / butanol materials, and the effect of different temperatures on the membrane separation performance was investigated. The results are shown in FIG. Figure 2 As shown. Figure 2 It can be seen that the flux and separation factor of the membrane show an upward trend with increasing temperature, which is very difficult to achieve in separation membranes.

[0054] 2. Study on the stability of pervaporation membrane relative to material concentration

[0055] The pervaporation membrane prepared in Example 1 was used to separate water / butanol materials with different concentration ratios at 70°C to investigate the effect of material concentration on the pervaporation membrane separation performance. The results are as follows: Figure 3 As shown in the figure, within the test range, the flux and separation factor both show an upward trend, indicating that under an ultra-high water concentration environment, the pervaporation membrane prepared in Example 1 can still maintain high flux and high separation accuracy.

[0056] This method uses a covalent organic framework (COF) as a material, introduces polyelectrolytes to reduce the COF pore size, utilizes covalent and electrostatic interactions to induce the regular arrangement of COF nanosheets, and simultaneously leverages the polyelectrolyte's strong hydrophilicity and water absorption to construct rapid water transport channels. Metal ions are introduced to regulate the water transport channels through electrostatic interactions and cation-π interactions. The polyelectrolytes synergize with the metal ions to simultaneously enhance the flux and separation factor of the COF pervaporation membrane. The covalent organic framework pervaporation hybrid membrane prepared by this method, with its sequentially controlled interlayer structure, can achieve high water flux and high-precision separation of water / butanol molecules. Its preparation method is convenient and simple.

[0057] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any person skilled in the art may utilize the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes for application in other fields. However, any simple modification, equivalent change, and modification of the above embodiments made in accordance with the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure, the pervaporation membrane comprising a substrate and a functional layer, characterized in that: The steps are as follows: (1) dissolving an aldehyde organic monomer in an organic solvent and mixing them uniformly to obtain an aldehyde monomer solution; dissolving an amino organic monomer in deionized water and mixing them uniformly to obtain an amino monomer solution; The aldehyde monomer solution is added to the amino monomer solution and allowed to stand for reaction; after the reaction is completed, the aqueous phase is taken and dialyzed to obtain a covalent organic framework nanosheet dispersion; (2) diluting the covalent organic framework nanosheet dispersion and adjusting the pH to neutral to obtain dispersion A; A polyelectrolyte aqueous solution was prepared and the pH was adjusted to neutral to obtain solution B; preparing a metal ion dispersion and adjusting the pH to neutral to obtain solution C; (3) Dispersion A and solution C are mixed at room temperature and stirred evenly, then solution B is added, stirred and heated to react, and after the reaction is completed, it is naturally cooled to room temperature to obtain a casting solution; (4) Filtering the casting solution onto the base membrane and vacuum drying to obtain a pervaporation membrane; The metal ion described in step (2) is any one of sodium ion, potassium ion, magnesium ion, calcium ion, zinc ion, copper ion, aluminum ion, and iron ion; the covalent organic framework nanosheet is any one of TpPa-SO3H or TpEB; and the polyelectrolyte is any one of polyethyleneimine, sodium alginate, polyacrylic acid, or polyethyleneamine.

2. The method for preparing a covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure according to claim 1, characterized in that: The concentration of the aldehyde monomer solution in step (1) is 1-10 mmol / L; the amino monomer solution is a mixture of an amino organic monomer and an auxiliary agent, the molar concentrations of the amino organic monomer and the auxiliary agent are both 1-10 mmol / L, and the molar ratio of the aldehyde monomer to the amino monomer is 1:(1-3); the static reaction time is 4-6 days, and the dialysis treatment time is 2-4 days; the auxiliary agent is sodium carbonate or p-toluenesulfonic acid.

3. The method for preparing a covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure according to claim 1, characterized in that: In step (2), the concentration of the covalent organic framework dispersion in dispersion A is 0.01-0.03 mg / ml, the concentration of the polyelectrolyte solution in solution B is 0.01-0.03 mg / ml, the concentration of the metal ion in solution C is 3-4 mmol / L, and the volume ratio of dispersion A:solution B:solution C is (1-2):(2-3):(1-2).

4. The method for preparing a covalent organic framework pervaporation hybrid membrane with sequentially controlled interlayer structure according to claim 1, characterized in that: In step (3), the dispersion A and solution C are mixed and stirred at room temperature for 8-15 minutes. After solution B is added, the reaction temperature is raised to 75-85°C and the reaction time is 0.9-1.2 hours.

5. Use of the covalent organic framework pervaporation hybrid membrane with a combined sequentially regulated interlayer structure obtained by the preparation method according to any one of claims 1 to 4 in water / butanol separation.

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