A sol-gel preparation method for mesoporous carbon membranes, and the mesoporous carbon membranes and their applications.

Abstract

This invention discloses a sol-gel preparation method for mesoporous carbon membranes, as well as the mesoporous carbon membranes and their applications. The preparation method includes: (1) dissolving phenolic compounds in a solvent and adding a template agent; (2) adding aldehyde compounds and amine compounds to obtain a mixture; (3) subjecting the mixture to a hydrothermal reaction to obtain an organic membrane precursor; and (4) carbonizing the organic membrane precursor at high temperature; wherein the solid content of the mixture is 20-30 wt%. The method of this invention significantly shortens the production cycle, has high preparation efficiency and success rate, can be molded to any size, and the obtained porous structure can withstand high-temperature treatment without collapsing. The obtained mesoporous carbon membrane can be applied to gas separation or liquid separation.

Description

Technical Field

[0001] This invention relates to the field of carbon membranes, and more specifically, to a sol-gel preparation method for mesoporous carbon membranes, as well as the mesoporous carbon membranes and their applications. Background Technology

[0002] Porous carbon materials, due to their well-developed pore structure, good chemical stability, corrosion resistance, and high conductivity, are widely used in adsorption, catalysis, electrochemistry, and energy and environmental fields. Carbon membranes are outstanding representatives of porous carbon materials. As a novel, efficient, and energy-saving inorganic separation membrane, they also possess advantages such as high specific surface area, high thermal stability, biocompatibility, and renewability. Combined with their excellent pore structure, they can distinguish gas molecules by size, making them particularly suitable for separating small molecules in gas mixtures or isomers with small kinetic radii in isomer mixtures, exhibiting high separation selectivity and permeability.

[0003] With increasingly stringent environmental protection requirements and the need for green development, the demands on the permeability and selectivity of carbon membranes are also rising. Researchers are making every effort to improve these two properties. For example, Kita et al. used porous aluminum with an average pore size of 1 μm and a porosity of 50% as a support, coated it with a phenolic resin solution, and then dried and carbonized it to obtain a carbon membrane. They found that the number of coatings had a significant impact on gas permeability and selectivity, with three coatings yielding better results. Centeno and Fuertes et al. coated a carbon support with a phenolic resin solution on an average pore size of 0.5 μm, and the resulting carbon membrane exhibited molecular sieving properties. Furthermore, Kolar et al. prepared a flat carbon support using thermosetting phenolic resin as a raw material, and then coated it with a phenolic resin solution, but it lacked selectivity. Therefore, preparing porous carbon materials with both specific pore structures and morphologies remains a significant challenge.

[0004] Good permeability and selectivity are often closely related to regular and ordered mesoporous structures. Therefore, the research and preparation of ordered mesoporous carbon membranes are becoming increasingly important and have attracted widespread attention from many scholars. Homogeneous carbon membranes have significant research value and room for improvement due to their simple preparation process, controllable pore structure, and relatively limited research on unsupported carbon membranes. Flat sheet carbon membranes, on the other hand, face difficulties in achieving industrial applications due to the inability to mass-produce them and the difficulty in reducing production costs. In contrast, single-channel tubular membranes, multi-channel tubular membranes, and capillary membranes, because they can be mass-produced, are expected to achieve industrial applications soon and therefore have very attractive application prospects.

[0005] Currently, the main methods for preparing carbon films are the soft-templating method and the hard-templating method. Compared to the hard-templating method, the soft-templating method uses soft-structured molecules or molecular aggregates as template agents, such as cationic, anionic, and nonionic surfactants and their aggregates. First, a micellar structure is formed in the synthesis solution. Then, under suitable acid-base conditions, an intermediate phase is formed with an oxygen-containing carbon precursor through hydrogen bonding and / or Coulomb forces. Finally, high-temperature heat treatment (also known as pyrolysis or calcination) carbonizes the intermediate phase, removes the template agent, and forms a porous structure, ultimately obtaining the carbon film. It is evident that carbon films prepared by the soft-templating method exhibit diverse shapes, are easy to construct, are convenient to operate, have a simple process, and allow for controllable carbon film morphology. Moreover, the carbon material has ordered channels, adjustable pore size, high thermal stability, and specific surface area, making it an ideal method for carbon film preparation.

[0006] In the preparation of carbon membranes, the selection of raw materials is crucial. Phenolic resin (PFR) is an ideal precursor for preparing porous carbon membranes due to its wide availability, low price, and high carbon content. Zhou and Centenod et al. used PFR as a precursor and employed impregnation-coating and impregnation methods, using porous ceramic tubes or porous resin-carbon materials as supports, to prepare selective carbon membranes with well-developed pore structures, high specific surface areas, and few defects, exhibiting high separation performance.

[0007] In Chinese patent CN1821182A, Zhao et al. prepared mesoporous carbon by solvent evaporation self-assembly. Although the precursor in the claims is one or more of phenolic resin, polyimide, polypyrrole, polyacrylamide, polyacrylonitrile or polyvinylpyridine, all 17 preparation examples selected phenolic resin PFR.

[0008] Therefore, with the in-depth study of the soft template method synthesis route and assembly mechanism, using inexpensive and easily prepared PFR as a precursor, the soft template method to prepare unsupported carbon films will become a new research method or preparation method for multifunctional carbon films. However, these preparation methods still have problems such as many steps, difficult drying (such as special methods such as supercritical drying), long time consumption, and low success rate. Summary of the Invention

[0009] To address the shortcomings of existing preparation processes, such as long synthesis time, high energy consumption, difficulty in surface chemical control, cumbersome carbon film formation, and poor permeability due to insufficient mesopores, this invention provides a rapid, simple, and efficient sol-gel preparation method for mesoporous carbon membranes, as well as the mesoporous carbon membranes and their applications. This invention utilizes phenolic compounds, amine compounds, and aldehydes as raw materials, and under the guidance of a template agent, a hydrothermal synthesis and sol-gel reaction process is employed to generate a cross-linked network-like mesoporous organic membrane precursor. This organic membrane precursor possesses sufficient strength and requires no special drying method; conventional drying yields the organic membrane, which is then carbonized at high temperature to prepare a non-supported mesoporous carbon membrane. This technology enables the rapid, simple, and highly efficient preparation of porous carbon membranes rich in mesoporous structures.

[0010] One objective of this invention is to provide a sol-gel preparation method for mesoporous carbon membranes, comprising the following steps:

[0011] (1) Dissolve the phenolic compound in a solvent and add a template agent;

[0012] (2) Add aldehydes and amines to obtain a homogeneous mixture;

[0013] (3) The mixture is subjected to a hydrothermal reaction and then conventionally dried to obtain an organic membrane precursor;

[0014] (4) The organic membrane precursor is carbonized at high temperature.

[0015] The solid content of the mixture is 20-30 wt%, preferably 20-25 wt%.

[0016] In the sol-gel preparation method described above, the phenolic compound is preferably at least one of phenol, resorcinol, and phloroglucinol.

[0017] In the sol-gel preparation method described above, the template agent is preferably at least one of F127, P123, F108, and B50.

[0018] In the sol-gel preparation method described above, the amine compound is preferably at least one of ethylenediamine, hexamethylenediamine, propylenediamine, and butanediamine.

[0019] In the sol-gel preparation method described above, the aldehyde compound is at least one of formaldehyde, polyoxymethylene, and furfural.

[0020] In the sol-gel preparation method described above, the molar ratio of the phenolic compound to the aldehyde compound is (1:2) to (1:4), specifically 1:2, 1:2.5, 1:3, 1:3.5, 1:4, etc.

[0021] In the sol-gel preparation method described above, the molar ratio of the phenolic compound to the amine compound is (1:0.01) to (1:1), preferably (1:0.02) to (1:0.15), and can specifically be 1:0.01, 1:0.02, 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.5, 1:1, etc.

[0022] In the sol-gel preparation method described above, the molar ratio of the phenolic compound to the template agent is (1:0.002) to (1:0.02), preferably (1:0.003) to (1:0.02), and specifically can be 1:0.002, 1:0.003, 1:0.005, 1:0.008, 1:0.01, 1:0.012, 1:0.015, 1:0.018, 1:0.02, etc.

[0023] In the sol-gel preparation method described above, the solvent is preferably one or both of water and ethanol.

[0024] In the sol-gel preparation method described above, step (2) preferably includes:

[0025] (2-1) Add 1 / 2 to 2 / 3 of the aldehyde compound, (2-2) then add the amine compound, (2-3) then add the remaining aldehyde compound.

[0026] In step (3) of the sol-gel preparation method described above, the obtained mixture is loaded into a mold, and after defoaming is completed, it is transferred into a reaction vessel to carry out the hydrothermal reaction of sol-gel transformation.

[0027] In the sol-gel preparation methods described above, the defoaming method shall be at least one of vibration, ultrasound, or long-term static stopping.

[0028] In the sol-gel preparation method described above, the mold is any one of a single-channel tubular membrane mold, a multi-channel tubular membrane mold, a plate membrane mold, a barrel membrane mold, or a capillary membrane mold.

[0029] In the sol-gel preparation method described above, the hydrothermal reaction temperature is preferably 80–150°C, and more preferably 85–120°C.

[0030] In the sol-gel preparation method described above, the hydrothermal reaction time is preferably 15 min to 12 h, and more preferably 30 min to 6 h.

[0031] In step (4) of the sol-gel preparation method described above, high-temperature carbonization includes raising the temperature from room temperature to 150-450°C at a rate of 0.5-3°C / min under inert gas conditions, holding the temperature for 30 min-2 h, and then raising the temperature to 500-1000°C at a rate of 1-5°C / min and holding the temperature for 60 min-5 h.

[0032] This invention uses phenolic compounds, amine compounds, and aldehydes as raw materials, a template agent as a structure directing agent, and an organic amine as a structure promoter. The amine reacts with phenols / aldehydes via the Mannich reaction, and the phenol-aldehyde reaction generates precursors. Furthermore, under the action of the directing agent, a condensation reaction occurs, particularly in a hydrothermal reactor, where the sol-gel reaction rapidly forms a cross-linked network structure. Therefore, the reaction time is significantly shortened and the preparation efficiency is significantly improved. In addition, because the homogeneous mixture (actually a sol) is injected into molds of various shapes, a sol-gel reaction occurs to obtain gels with different configurations. These gels not only have sufficient strength for simple demolding and conventional drying, but their porous structure can withstand high-temperature treatment without collapsing. Therefore, this is a highly efficient and high-success-rate method for preparing mesoporous carbon membranes.

[0033] The most significant feature of this invention is that phenolic amine undergoes the Mannich reaction to form benzoxazine, which then copolymerizes with phenolic resin to self-assemble into a porous polymer rich in mesopores (organic membrane precursor). High-temperature carbonization yields a mesoporous carbon membrane. Furthermore, a hydrothermal reactor is used for a sol-gel reaction, rapidly cross-linking and weaving to form gels (organic membrane precursors) of different shapes (configurations). These gels not only possess sufficient mechanical strength for conventional drying and high-temperature carbonization but also exhibit high preparation efficiency and a high success rate. In particular, the sol-gel preparation method allows for molding to any size, significantly reducing film-forming steps and improving both preparation efficiency and success rate.

[0034] A second objective of this invention is to provide a mesoporous carbon membrane obtained by the sol-gel preparation method.

[0035] The third objective of this invention is to provide the application of the mesoporous carbon membrane obtained by the preparation method in the field of gas or liquid separation, such as C8 mixed liquid separation.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] 1) Phenolic compounds, amine compounds and aldehyde compounds are used as reactants. The raw materials are conventional chemicals, especially phenols and aldehydes, which are widely available, inexpensive and easy to obtain.

[0038] 2) The use of non-supported molds greatly simplifies the molding process, significantly shortens the production cycle, and makes large-scale industrial applications more possible.

[0039] 3) Choose an aqueous solution system, which is simple and pollution-free, environmentally friendly, easy to scale up, and easy to promote green production.

[0040] 4) Amine compounds serve a dual purpose: they act as a source of secondary amines to assist the Mannich reaction, and as a base catalyst to promote the phenolic polycondensation reaction, forming a cross-linked network to ensure that the porous structure does not collapse.

[0041] 5) A sol with a suitable solid content undergoes a sol-gel reaction in a hydrothermal reactor, achieving a rapid transformation from sol to gel. This not only significantly accelerates the reaction rate (from several days in the past to just a few hours), but also ensures that the product gains sufficient strength due to cross-linking and interweaving, enabling it to withstand conventional drying (currently mostly critical or complex drying). Ultimately, carbonization is achieved to obtain a carbon film, resulting in high efficiency and a high success rate.

[0042] This invention has successfully prepared barrel-shaped carbon membranes in a particularly fast, simple and efficient manner. It is expected to be used in separation components for carbon membrane separation, or as a support membrane supplemented with a more finely controlled separation layer for gas separation or separation of organic isomers. Attached Figure Description

[0043] Figure 1 The organic membrane precursor obtained in Example 1. Detailed Implementation

[0044] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0045] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0046] This invention uses phenolic compounds, amine compounds, and formaldehyde as raw materials. Under the structural guidance of a template agent, and with alcohol / aqueous solution as a solvent, a cross-linked network copolymer is prepared through a sol-gel reaction under hydrothermal conditions. This copolymer is a cross-linked copolymer of benzoxazine resin precursor and phenolic resin precursor. The copolymer is a porous polymer rich in mesopores. Under suitable molds, it can be prepared into organic membrane precursors of various shapes, up to mesoporous carbon membranes.

[0047] According to a preferred embodiment of the present invention, the specific steps include:

[0048] 1) Dissolve phenolic compounds in a solvent;

[0049] 2) Add the template agent and dissolve it completely;

[0050] 3) Add 1 / 2 of the aldehyde compound during stirring;

[0051] 4) Add amine compounds;

[0052] 5) Add the remaining aldehyde compounds to obtain a homogeneous mixture;

[0053] 6) Pour the aforementioned mixture into a mold, remove the bubbles, and then pour it into a hydrothermal reactor;

[0054] 7) Move the reactor to the set temperature for hydrothermal reaction;

[0055] 8) After demolding, the product is dried to obtain the organic membrane precursor;

[0056] 9) The organic membrane precursor is subjected to routine drying;

[0057] 10) High-temperature carbonization treatment yields non-supported mesoporous carbon membranes.

[0058] According to a preferred embodiment of the present invention, the molar ratio of phenolic compound to aldehyde compound is (1:2) to (1:4), the molar ratio of phenolic compound to amine compound is (1:0.01) to (1:1), and the molar ratio of phenolic compound to template agent is (1:0.002) to (1:0.02).

[0059] According to a preferred embodiment of the present invention, the solid content of the mixture is 20-30 wt%, specifically 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, etc.

[0060] According to a preferred embodiment of the present invention, the phenolic compound in the preparation method is one or a combination of phenol, resorcinol, and phloroglucinol; the amine compound is any one or a combination of ethylenediamine, hexamethylenediamine, propylenediamine, and butanediamine; and the template agent is any one or a combination of F127, P123, F108, and B50.

[0061] According to a preferred embodiment of the present invention, the mixture in the preparation method is loaded into a mold, which includes any form of mold such as a capillary, a single-channel membrane, a multi-channel membrane, a plate membrane, or a barrel membrane; the removal of air bubbles can be achieved by any method or combination thereof, such as vibration, ultrasound, or long-term static stopping.

[0062] According to a preferred embodiment of the present invention, the temperature range of the hydrothermal reaction is 80-150°C (preferably 85-120°C), and the duration of the hydrothermal reaction is 15 min-12 h (preferably 30 min-6 h); the drying method is conventional drying, without special humidity control, and drying in an oven at 50-80°C for 4-24 h is sufficient.

[0063] According to a preferred embodiment of the present invention, the porous polymer rich in mesoporous channels prepared by the above method is then placed in a carbonization furnace and heated from room temperature to 150-400°C at a rate of 0.5-3°C / min under inert gas protection, and held at the temperature for 30 min-2 h. The temperature is then further increased to 500-1000°C at a rate of 1-5°C / min and held at the temperature for 60 min-5 h, thereby obtaining a non-supported mesoporous-microporous carbon membrane with uniform size and well-preserved morphology.

[0064] Example 1: Preparation of organic membrane precursor

[0065] Weigh 9g of resorcinol and place it in a beaker. Add 35.7g of water and 35.7g of ethanol and stir at room temperature. After dissolving, add 4.13g of surfactant F127 and 9.95g of 37% formaldehyde solution while stirring. During stirring, add 0.476g of hexamethylenediamine and then add 9.95g of formaldehyde solution. After obtaining a white colloid, weigh 5.5g of the above reaction solution with a solid content of 20.0% and put it into a cylindrical mold with an outer diameter of 26mm, an inner diameter of 22.4mm, and a height of 39.5mm. Then transfer it to a hydrothermal reactor. Place the mold and reactor containing the reaction solution in an ultrasonic vibration tank to expel bubbles for 5 minutes. After sealing, transfer it to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. After opening the lid and demolding, take out the molded polymer and dry it in an oven at 50℃ for 24 hours to obtain the non-supported mesoporous organic membrane precursor.

[0066] Example 2: Preparation of organic membrane precursor

[0067] Weigh 9g of resorcinol and place it in a beaker. Add 27g of water and 27g of ethanol and stir at room temperature. After dissolving, add 4.13g of surfactant F127 and 11.6g of 37% formaldehyde solution while stirring. During stirring, add 0.476g of hexamethylenediamine and then add 11.6g of formaldehyde solution. After obtaining a white colloid, weigh 10.5g of the above reaction solution with a solid content of 24.4% and put it into a tubular mold with an outer diameter of 26mm, an inner diameter of 22.4mm and a height of 79mm. Place the mold containing the reaction solution in an ultrasonic vibration tank to expel bubbles for 5 minutes. After sealing, transfer it to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. After opening the lid and demolding, take out the molded polymer and dry it in an oven at 50℃ for 24 hours to obtain the non-supported mesoporous organic membrane precursor.

[0068] Example 3: Preparation of organic membrane precursor

[0069] Weigh 9g of resorcinol and place it in a beaker. Add 19g of water and 19g of ethanol and stir at room temperature. After dissolving, add 4.13g of surfactant F127 and 13.3g of 37% formaldehyde solution while stirring. During stirring, add 0.476g of hexamethylenediamine and then add 13.3g of formaldehyde solution. After obtaining a white colloid, weigh 5.5g of the above reaction solution with a solid content of 30.0% and put it into a cylindrical mold with an outer diameter of 26mm, an inner diameter of 22.4mm, and a height of 39.5mm. Place the mold containing the reaction solution in an ultrasonic vibration tank to expel bubbles for 5 minutes. After sealing, transfer it to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. After opening the lid and demolding, take out the molded polymer and dry it in an oven at 50℃ for 24 hours to obtain the non-supported mesoporous organic membrane precursor.

[0070] Example 4: Preparation of organic membrane precursor

[0071] Weigh 9g of resorcinol and place it in a beaker. Add 27g of water and 27g of ethanol and stir at room temperature. After dissolving, add 4.13g of surfactant F127 and 9.95g of 37% formaldehyde solution while stirring. During stirring, add 0.761g of hexamethylenediamine and then 9.95g of formaldehyde solution. After obtaining a white colloid, weigh 5.5g of the above reaction solution with a solid content of 24.2% and put it into a single-channel mold with an outer diameter of 26mm, an inner diameter of 22.4mm, and a height of 39.5mm. Place the mold containing the reaction solution in an ultrasonic vibration tank to expel bubbles for 5 minutes. After sealing, transfer it to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. After opening the lid and demolding, take out the molded polymer and dry it in an oven at 50℃ for 24 hours to obtain the non-supported mesoporous organic membrane precursor.

[0072] Example 5: Preparation of organic membrane precursor

[0073] Weigh 9g of resorcinol and place it in a beaker. Add 27g of water and 27g of ethanol and stir at room temperature. After dissolving, add 4.13g of surfactant F127 and 13.3g of 37% formaldehyde solution while stirring. During stirring, add 0.761g of hexamethylenediamine and then add 13.3g of formaldehyde solution. After obtaining a white colloid, weigh 5.5g of the above reaction solution with a solid content of 25.1% and put it into a cylindrical mold with an outer diameter of 26mm, an inner diameter of 22.4mm and a height of 39.5mm. Place the mold containing the reaction solution in an ultrasonic vibration tank to expel bubbles for 5 minutes. After sealing, transfer it to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. After opening the lid and demolding, take out the molded polymer and dry it in an oven at 50℃ for 24 hours to obtain the non-supported mesoporous organic membrane precursor.

[0074] Example 6: Preparation of organic membrane precursor

[0075] Weigh 9g of resorcinol and place it in a beaker. Add 27g of water and 27g of ethanol and stir at room temperature. After dissolving, add 4.13g of surfactant F127 and 11.6g of 37% formaldehyde solution while stirring. During stirring, add 0.951g of hexamethylenediamine and then add 11.6g of formaldehyde solution. After obtaining a white colloid, weigh 5.5g of the above reaction solution with a solid content of 24.8% and put it into a cylindrical mold with an outer diameter of 26mm, an inner diameter of 22.4mm and a height of 39.5mm. Place the mold containing the reaction solution in an ultrasonic vibration tank to expel bubbles for 5 minutes. After sealing, transfer it to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. After opening the lid and demolding, take out the molded polymer and dry it in an oven at 50℃ for 24 hours to obtain the non-supported mesoporous organic membrane precursor.

[0076] Example 7: Preparation of Organic Membrane Precursors

[0077] Weigh 9g of resorcinol and place it in a beaker. Add 27g of water and 27g of ethanol and stir at room temperature. After dissolving, add 4.13g of surfactant F127 and 6.6g of 37% formaldehyde solution while stirring. During stirring, add 0.476g of hexamethylenediamine and then 6.6g of formaldehyde solution. After obtaining a white colloid, weigh 5.5g of the above reaction solution with a solid content of 22.9% and put it into a cylindrical mold with an outer diameter of 26mm, an inner diameter of 22.4mm, and a height of 39.5mm. Place the mold containing the reaction solution in an ultrasonic vibration tank to expel bubbles for 5 minutes. After sealing, transfer it to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. After opening the lid and demolding, take out the molded polymer and dry it in an oven at 50℃ for 24 hours to obtain the non-supported mesoporous organic membrane precursor.

[0078] Example 8: Preparation of organic membrane precursor

[0079] Weigh 9g of resorcinol and place it in a beaker. Add 27g of water and 27g of ethanol and stir at room temperature. After dissolving, add 4.13g of surfactant F127 and 8.3g of 37% formaldehyde solution while stirring. During stirring, add 0.476g of hexamethylenediamine and then add 8.3g of formaldehyde solution. After obtaining a white colloid, weigh 5.5g of the above reaction solution with a solid content of 23.4% and put it into a cylindrical mold with an outer diameter of 26mm, an inner diameter of 22.4mm, and a height of 39.5mm. Place the mold containing the reaction solution in an ultrasonic vibration tank to expel bubbles for 5 minutes. After sealing, transfer it to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. After opening the lid and demolding, take out the molded polymer and dry it in an oven at 50℃ for 24 hours to obtain the non-supported mesoporous organic membrane precursor.

[0080] Example 9: Preparation of Mesoporous Carbon Membranes

[0081] The organic membrane precursor prepared in Example 8 was placed in a carbonization furnace for heat treatment. Under the protection of inert gas N2, the temperature was increased from room temperature to 400°C at a rate of 1°C / min and held for 30 min. The temperature was then increased to 790°C at a rate of 1°C / min and held for 300 min. The membrane was then naturally cooled to room temperature to obtain a non-supported mesoporous carbon membrane with uniform size and good morphology.

[0082] Example 10 Separation Test

[0083] The unsupported mesoporous carbon membrane prepared in Example 9 was subjected to a PX / OX separation test. The PX concentration after separation was 1.2 times higher than that before separation, and the PX concentration was 50%, indicating that the separation effect was very good.

[0084] Comparative Example 1:

[0085] 9g of resorcinol was weighed and placed in a beaker. 14g of water and 14g of ethanol were added and stirred at room temperature. After dissolution, 4.13g of surfactant F127 was added, and 16.58g of 37% formaldehyde solution was added while stirring. During stirring, 0.951g of hexamethylenediamine was added, followed by 16.58g of formaldehyde solution. After obtaining a white colloid, 5.5g of the above reaction solution with a solid content of 35.0% was weighed and placed into a cylindrical mold with an outer diameter of 26mm, an inner diameter of 22.4mm, and a height of 39.5mm. The mold containing the reaction solution was placed in an ultrasonic vibration tank for 5 minutes to remove bubbles. After sealing, it was transferred to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. During the demolding process, it was found that demolding was almost impossible (the organic matter adhered very firmly to the mold). If strong demolding was performed, the entire preform would shatter, and the desired shape of the organic film precursor could not be obtained.

[0086] Comparative Example 2:

[0087] 9g of resorcinol was weighed and placed in a beaker. 40.3g of water and 40.3g of ethanol were added and stirred at room temperature. After dissolution, 5.15g of surfactant F127 was added, and 6.63g of 37% formaldehyde solution was added while stirring. During stirring, 0.476g of hexamethylenediamine was added, followed by 6.63g of formaldehyde solution. After obtaining a white colloid, 5.5g of the above reaction solution with a solid content of 18% was weighed and placed into a cylindrical mold with an outer diameter of 26mm, an inner diameter of 22.4mm, and a height of 39.5mm. The mold containing the reaction solution was placed in an ultrasonic vibration tank for 5 minutes to expel bubbles. After sealing, it was transferred to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. When the lid was opened and the mold was removed, it was found that no gel was formed and the mixture was still in liquid state (strictly speaking, it was a mixture in which the colloid and liquid were separated from each other). It was impossible to obtain a non-supported mesoporous organic membrane precursor.

[0088] Comparative Example 3:

[0089] 9g of resorcinol was weighed and placed in a beaker, along with 27g of water and 27g of ethanol. The mixture was stirred at room temperature until dissolved. 4.13g of surfactant F127 was then added, followed by 0.476g of hexamethylenediamine during stirring. Then, 13.2g of formaldehyde solution was added, resulting in a white colloid. 5.5g of the reaction solution (22.9% solids) was weighed and placed into a cylindrical mold with an outer diameter of 26mm, an inner diameter of 22.4mm, and a height of 39.5mm. The mold containing the reaction solution was placed in an ultrasonic vibration bath for 5 minutes to remove bubbles. After sealing, it was transferred to an oven set to a stable temperature of 90℃ for 4 hours of hydrothermal reaction. After demolding, the formed polymer was removed and dried in an oven at 50℃ for 24 hours to obtain the unsupported mesoporous organic membrane precursor. However, during the demolding process, it was found that the unsupported organic membrane precursor was difficult to demold, with a demolding success rate approximately 30% lower than that of Example 7.

Claims

1.A sol-gel preparation method of mesoporous carbon membrane, comprising the following steps: (1) dissolving a phenolic compound in a solvent and adding a template agent; (2) adding an aldehyde compound and an amine compound to obtain a mixed solution; (3) performing hydrothermal reaction on the mixed solution to obtain an organic membrane precursor; and (4) performing high-temperature carbonization on the organic membrane precursor; wherein the solid content of the mixed solution is 20-30 wt%; the molar ratio of the phenolic compound to the aldehyde compound is (1:2) - (1:4), the molar ratio of the phenolic compound to the template agent is (1:0.002) - (1:0.02), and the molar ratio of the phenolic compound to the amine compound is (1:0.01) - (1:1) ; step (2) comprises (2-1) adding 1 / 2-2 / 3 of the aldehyde compound, (2-2) then adding the amine compound, and (2-3) adding the remaining aldehyde compound; in step (3), the mixed solution is loaded into a mold, and after bubble removal, the mixed solution is moved into a reaction kettle for hydrothermal reaction; the mold comprises any one of a single-channel tube membrane mold, a multi-channel tube membrane mold, a barrel membrane mold, and a capillary tube membrane mold. 2.The sol-gel preparation method of claim 1, wherein: the solid content of the mixed solution is 20-25 wt%; in step (1) : the phenolic compound is at least one of phenol, resorcinol, and phloroglucinol; and / or the template agent is at least one of F127, P123, F108, and B50; and / or the molar ratio of the phenolic compound to the template agent is (1:0.003) - (1:0.02) ; in step (2) : the amine compound is at least one of ethylenediamine, hexanediamine, propylenediamine, and butanediamine; and / or the aldehyde compound is at least one of formaldehyde, polyformaldehyde, and furfural; and in step (2) : the molar ratio of the phenolic compound to the amine compound is (1:0.02) - (1:0.15) ; in step (3) : the mixed solution is loaded into a mold, and after bubble removal, the mixed solution is moved into a reaction kettle for hydrothermal reaction; the bubble removal method is at least one of vibration, ultrasonic, and long-time static standing; in step (3) : the temperature of the hydrothermal reaction is 80-150℃; and / or the time of the hydrothermal reaction is 15 min-12 h. 8.The sol-gel preparation method of claim 7, wherein: the temperature of the hydrothermal reaction is 85-120℃; and / or the time of the hydrothermal reaction is 30 min-6 h. 10.A mesoporous carbon membrane obtained by the sol-gel preparation method of any one of claims 1-9. 11.Use of the mesoporous carbon membrane obtained by the sol-gel preparation method of any one of claims 1-9 in the field of gas or liquid separation. ​ ​ ​ ​ ​ 3. The sol-gel preparation method according to claim 1, characterized in that ​ ​ ​ ​ 4. The sol-gel preparation method according to claim 1, characterized in that ​ ​ ​ 5. The sol-gel preparation method according to claim 1, characterized in that ​ ​ 6. The sol-gel preparation method according to claim 1, characterized in that ​ ​ ​ 7. The sol-gel preparation method according to claim 1, characterized in that ​ ​ ​ ​ ​ ​ 9. The sol-gel preparation method according to claim 1, characterized in that ​ ​ ​ ​

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