CN113772619B - Microporous channel membrane and preparation method thereof - Google Patents

Abstract

The invention discloses a preparation method of a microporous channel membrane, which comprises the steps of preparing an MXene precursor aqueous solution, taking 0.25-5 mL of chitosan aqueous solution with the mass concentration of 3-5 mg/mL, and fully mixing the chitosan aqueous solution with 5-83 mL of the MXene aqueous solution to prepare a precursor solution; filtering 0.8-1.5mL of precursor solution on a porous substrate by a vacuum filtering method, and then drying for 8-24 hours at room temperature; the membrane which is filtered on the ceramic substrate is placed in a protective atmosphere, the heat treatment temperature is 800-1000 ℃, and the calcination is carried out for 2-4 hours. And a microporous channel membrane prepared by the method is also provided. By controlling the parameters in the process of preparing the membrane, the micro-channel membranes with different performances can be obtained, and the most excellent micro-channel membrane of the row can be selected.

Description

A kind of microporous channel membrane and preparation method thereof

technical field

The invention relates to the field of membrane technology, in particular to a microporous channel membrane and a preparation method thereof.

Background technique

Microporous channel membrane, that is, two-dimensional materials are stacked to form a layered structure. By controlling the interlayer gap between two adjacent layers, a microporous membrane can be formed by stacking two-dimensional materials. This type of membrane has a nanocapillary network as a mass transfer channel. . Through size sieving, microporous channel membranes enable efficient molecular or ion sieving. The confinement effect of these two-dimensional nanocapillary channels drives water molecules to pass through the membrane quickly and orderly, and at the same time effectively separates or removes hydrated ions or molecules in water with a size larger than the two-dimensional channel. Therefore, nanoscale two-dimensional channel membranes have attracted much attention and are expected to become a new generation of high-performance membranes. However, due to the limitations of existing technical means, it is difficult to control the interlayer gap of two-dimensional materials at the scale of one tenth of a nanometer. In addition, existing two-dimensional materials such as graphene oxide and MXene (Ti ₃ C ₂ Tx,T=OH,F, H) The membrane formed by nanosheets will swell in water or some organic solvents, which will lead to serious attenuation of separation performance. Therefore, the two-dimensional microporous channel membrane is facing great challenges in ion screening and seawater desalination, and the existing two-dimensional Material preparation technology limits the large-scale development and application of such membranes.

"Science" (Science, 335 (2012) 442-444) magazine reported the preparation of submicron (0.1-10 μm) graphene oxide films by spray or spin coating. This graphene oxide film has unique transmission properties, any gas and liquid cannot penetrate the graphene oxide film, but water vapor can be transmitted at high speed without hindrance. However, the interlayer gap of graphene oxide membranes will increase to 1.3±0.1nm when immersed in water, so such membranes are difficult to remove ions and molecules with smaller hydration diameters in water.

"Nature" magazine (Nature, 550 (2017) 380-383) reported that the introduction of hydrated cations of different sizes into the graphene oxide stack can achieve precise regulation of the interlayer spacing of the graphene film up to one tenth of a nanometer. In addition, when the interlayer gap of the membrane is regulated by a cation, the membrane can effectively intercept all ions in the salt solution including the cation itself and all ions larger than the hydration diameter of the cation, and at the same time keep water molecules passing through quickly, so that the salt ions and pure water are efficiently enriched on the feed side and permeate side of the graphene membrane, respectively. However, this method is still difficult to effectively suppress the swelling decay of graphene oxide membranes in water.

Contents of the invention

Therefore, the technical problem to be solved by the present invention is to propose a microporous channel membrane formed of two-dimensional materials and a preparation method thereof, so as to overcome the above-mentioned defects of the prior art and explore a way to prepare a high-performance microporous membrane.

The technical scheme of the present invention is, a kind of preparation method of microporous channel membrane:

a. Precursor solution preparation: dissolve lithium fluoride in 6-9mol/L hydrochloric acid solution, pass in inert gas and stir for 1-2 hours, then add Ti ₃ AlC ₂ , lithium fluoride, hydrochloric acid solution and Ti ₃ The ratio of _AlC2 is: 0.5～1.5:15-25:0.5～1.5, the unit is g/mL/g, keep the reaction temperature at 20～35°C and continue stirring for 12～24 hours under the condition of feeding inert gas; The solution after the above reaction was ultrasonicated for 5 to 15 minutes, washed with deionized water and centrifuged for 3 to 5 times, the centrifugal speed was 3000 to 5000 rpm, and the centrifugation time was 4 to 10 minutes. The sediment at the bottom, after adding deionized water and shaking to disperse the sediment, keep the centrifugation speed of 3000-5000 rpm for 0.5-1.5 hours, then take the supernatant and dilute it to a 60-100mg/mL solution to obtain MXene Precursor aqueous solution;

b. Take 0.25-5 mL of the acetic acid solution with a mass concentration of 3-5 mg/mL chitosan, and fully mix it with 5-83 mL of the MXene aqueous solution obtained in step a to prepare a precursor solution;

c. Deposition: filter 0.8-1.5 mL of precursor solution on the porous substrate by vacuum filtration, and then dry at room temperature for 8-24 hours;

d. Heat treatment: place the film above suction-filtered on the ceramic substrate in a protective atmosphere, heat treatment temperature is 800-1000° C., and calcined for 2-4 hours.

In step a, in order to wash away the acid in the solution, the solution is adjusted from acidity to close to neutral, and in order that the MXene nanosheets can be fully peeled off and dispersed, the first 3-5 times of centrifugal cleaning, after each cleaning The supernatant was discarded. After the 3rd to 5th time, disperse the precipitate and continue to centrifuge for a long time, then take the supernatant and dilute it into a precursor aqueous solution. The previous operation is cleaning, and after cleaning, the sediment is added with water to disperse the sediment.

The acetic acid solution in step b preferably has a concentration of 0.02-0.1mol/L.

The heat treatment process is a process of reducing MXene and carbonizing and crystallizing chitosan. MXene is Ti ₃ C ₂ T _x , where T=can be OH, F, H. Several components are present at the same time.

According to a method for preparing a microporous channel membrane of the present invention, preferably, the mixing in step b is performed by magnetic stirring. Magnetic stirring can make chitosan and MXene solution fully mixed.

According to a method for preparing a microporous channel membrane of the present invention, preferably, 8-12 mL of deionized water is added to the solution before mixing in step b.

According to a method for preparing a microporous channel membrane of the present invention, preferably, the inert gas in step a is nitrogen or argon.

According to a method for preparing a microporous channel membrane of the present invention, preferably, the porous substrate in step c is a porous alumina ceramic substrate.

According to a method for preparing a microporous channel membrane of the present invention, preferably, the protective atmosphere in step d is nitrogen or argon.

The present invention also provides a microporous channel membrane formed by the two-dimensional material prepared by the above preparation method, the microporous channel membrane comprising a porous base layer and a Ti3C2/graphene composite layer on the porous base layer; the Ti3C2/ The graphene composite layer is obtained by compounding the upper and lower graphene layers and the Ti ₃ C ₂ layer sandwiched between the two graphene layers. The graphene layer is a fragment discontinuous structure, and the Ti ₃ C ₂ layer is also Fragmental discontinuity structure;

Ti ₃ C ₂ is prepared by exfoliating Ti ₃ AlC ₂ and removing the functional groups introduced by the exfoliation to form a sheet structure; the graphene layer is obtained by carbonizing and crystallizing chitosan on the Ti ₃ C ₂ sheet.

Preferably, the concentration ratio of the two precursors MXene and chitosan is 0.08:27.2˜0.83:27.2.

MXene is Ti ₃ C ₂ T _x , where T=OH, F, H.

Ti ₃ AlC ₂ is the initial raw material. After etching, Al is removed, so that Ti ₃ AlC ₂ is peeled off from bulk to flake. Because of acid etching, new functional groups are introduced into the etched Ti ₃ C ₂ layer: -F, -OH and -O-, thereby forming Ti ₃ C ₂ T _x . After heat treatment, these functional groups are removed to form Ti ₃ C ₂ .

Carbonization crystallization corresponds to the previous heat treatment process.

Ti ₃ C ₂ must be separated one by one, and the graphene is interlaced in the upper and lower layers of Ti ₃ C ₂ . Each bar represents a nanosheet.

The finished film is deposited on a porous substrate with chemical forces between the two. Because the finished film is thin, a porous substrate is needed as a support to enhance its mechanical strength, and it is not easy to be damaged during use.

According to the microporous channel membrane formed by the two-dimensional material of the present invention, preferably, the porous substrate is a porous alumina ceramic substrate.

The pore size of the porous substrate is 0.9-1.1 μm. In order to prevent the Ti3C2/graphene composite layer from being partially detached from the porous substrate, the thickness generally cannot be greater than 500 nm, such as 30-500 nm. The thickness of the film can be controlled by controlling the volume of the precursor solution used for suction filtration to form the film. However, as a membrane, it is generally required that the membrane has high flux and high cut-off rate, so in our research, we mainly study the performance of the 30-100nm membrane. This is the thinnest film thickness range that our preparation conditions can achieve. In subsequent implementations (3, 4, 5, 6), the flux and salt rejection rate of membranes with different thicknesses obtained under different experimental conditions were also compared.

According to the microporous channel membrane formed by the two-dimensional material of the present invention, preferably, there is an intermolecular force between the graphene layer and titanium carbide (ie Ti ₃ C ₂ ), and they are stacked together. But the upper and lower layers are not directly connected.

Graphene oxide films, which are widely concerned at present, are mainly composed of graphene oxide nanosheets or MXene nanosheets. There are a large number of oxygen-containing functional groups on these nanosheets, which makes it easy for the nanosheets to be uniformly dispersed in water to facilitate subsequent film preparation. However, the presence of these functional groups makes the film swell easily when immersed in water or in a humid environment, weakening the stability of the film. And it is difficult to control the interlayer gap of the film to the sub-nanometer level. The present invention utilizes heat treatment results to remove functional groups on MXene nanosheets, and at the same time, carbonizes and crystallizes chitosan to form graphene links on the surface of Ti ₃ C ₂ nanolayers, thereby effectively controlling two-dimensional channels to the sub-nanometer level, and without The functional group hinders the transport of water in the channel, and the water flux can be greatly improved. The removal of functional groups on the surface of the nanosheets overcomes the swelling of the membrane in water and its stability. The invention can control the film thickness below 100nm to effectively reduce the thickness of the selective layer and effectively improve the water flux of the film. The microporous channel membrane prepared by the invention exhibits superior performance in water flux and desalination rate.

The beneficial effects of the present invention are:

The chitosan and porous ceramic substrate used in the present invention are common cheap industrial raw materials and industrial products. The vacuum filtration used is a commonly used method for preparing membranes, which is helpful for the scale-up production of the present invention. In addition, by controlling various parameters in the membrane preparation process, microchannel membranes with different properties can be obtained and the most superior microchannel membrane can be selected.

The water flux and salt cut-off rate of the membrane are in the range of 67.0-130.4 under the test conditions of 20°C when 2000mg/L NaCl solution is used as the extraction solution. For LLMH, the salt interception rate is as high as 99.9%.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the microporous channel membrane of the present invention.

FIG. 2 is a partially enlarged schematic diagram of the Ti ₃ C ₂ /graphene composite layer in FIG. 1 .

Fig. 3a is an optical photo of Ti ₃ C ₂ /graphene film on a ceramic substrate.

Figure 3b is a scanning electron microscope (SEM) picture of the film - cross section.

Detailed ways

Example 1

Precursor solution preparation:

The preparation process of MXene (Ti ₃ C ₂ Tx, T=OH, F, H): Dissolve 1.0g lithium fluoride in 20ml of 9mol/L hydrochloric acid solution, blow in nitrogen and stir for 1.5 hours, then add 1.0g Ti ₃ AlC ₂ , keep the reaction temperature at 25°C and continue to stir for 22 hours under the condition of nitrogen gas; the above-mentioned solution after the reaction is ultrasonicated for 10 minutes, washed with deionized water and centrifuged for 4 times, and the centrifuged speed is 3500 rpm , the centrifugation time is 5 minutes, and the bottom sediment is retained during the 4 cleaning processes. After adding deionized water for the 5th time and shaking to disperse the sediment, keep the centrifugation speed of 3500 rpm for 1 hour, then take the supernatant, and Dilute to 83mg/L solution to obtain MXene precursor aqueous solution.

Chitosan precursor solution preparation process: 50mg chitosan was dissolved in 10mL acetic acid solution of 0.05mol/L, fully stirred by a magnetic stirrer for 4 hours, chitosan was fully dissolved in the acetic acid solution, and the solution concentration was 5mg/mL Chitosan precursor solution.

Example 2

Precursor solution preparation:

The preparation process of MXene (Ti ₃ C ₂ Tx, T=OH, F, H): Dissolve 1.5g lithium fluoride in 20ml of 8mol/L hydrochloric acid solution, blow in nitrogen and stir for 2 hours, then add 1.2g Ti ₃ AlC ₂ , keep the reaction temperature at 28°C and continue to stir for 18 hours under the condition of nitrogen gas; the above-mentioned solution after the reaction is ultrasonicated for 12 minutes, washed with deionized water and centrifuged for 4 times, and the centrifuged speed is 3800 rpm , the centrifugation time is 6 minutes, and the sediment at the bottom is retained during the 4 times of washing. After adding deionized water for the 5th time and shaking to disperse the sediment, keep the centrifugal speed of 4000 rpm for 1.2 hours, then take the supernatant, and Dilute to 90mg/L solution to obtain MXene precursor aqueous solution.

Chitosan precursor solution preparation process: 35mg chitosan was dissolved in 10mL acetic acid solution of 0.05mol/L, and fully stirred by a magnetic stirrer for 4 hours to obtain a chitosan precursor solution with a solution concentration of 3.5mg/mL.

Example 3

5 mL of the MXene solution in Example 1 was successively dispersed in 10 mL of deionized water, and 0.25 mL of 5 mg/mL chitosan solution in Example 1 was added, and the solution was stirred for 6 hours by a magnetic stirrer to fully mix the solution, and finally a precursor solution was obtained. 1 mL of the precursor was filtered on the porous ceramic substrate by vacuum filtration, and then dried at room temperature for 16 hours, and then placed in an argon-protected atmosphere and calcined at 900°C for 3 hours. Finally, a microporous channel membrane is obtained.

Figure 2 is a photo of the obtained microporous channel membrane and a scanning electron microscope (SEM) image of the cross section, from which we can see that the membrane is stacked by two-dimensional nanosheets. The thickness of the selected layer of the film can be controlled by adjusting the volume of the precursor solution, and the film thickness can be controlled at 30-100nm, and the film within this thickness range is used for performance test research. This thickness does not include the thickness of the porous substrate. We mainly study the water flux and salt interception performance of the membrane with a thickness in the range of 30-100nm, because the thinner the membrane, the higher the water flux, but usually the lower the rejection rate. When optimizing membrane performance parameters, it is often necessary to balance flux and rejection. The volume of the precursor solution is 0.8-1.5 mL when the membrane is prepared by suction filtration.

The test results of water flux and salt rejection rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 82.8LMH and the salt rejection rate is as high as 20°C under the test conditions. Up to 99.9%. The experimental data show that the membrane has good water treatment performance.

Example 4

Using a method similar to Example 3 to prepare a film, 1 mL of 5 mg/mL chitosan solution and 5 mL of 83 mg/mL MXene in Example 1 were fully dispersed in 10 mL of water, and then a film with a similar structure was obtained.

The test results of water flux and salt rejection rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 99.0LMH and the salt rejection rate is as high as 20°C under the test conditions. Up to 99.9%.

Example 5

Adopt the method of preparing film similar to Example 3, just take 2mL of 5mg/mL chitosan solution and 5mL of 83mg/mL MXene and fully disperse in 10mL of water, then obtain the film with similar structure.

The test results of water flux and salt rejection rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 68.9LMH and the salt rejection rate is as high as 20°C under the test conditions. Up to 99.9%.

Example 6

Using the same membrane preparation method as in Example 3, except that 3 mL of 5 mg/mL chitosan solution and 5 mL of 83 mg/mL MXene were fully dispersed in 10 mL of water, and then a film with a similar structure was obtained.

The test results of water flux and salt rejection rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 67.0LMH and the salt rejection rate is as high as 20°C under the test conditions. Up to 99.9%.

Example 7

Adopt the method of preparing film similar to Example 4, just change the drying time to 8 hours. Since the film is aired at room temperature for 8 hours, it is not enough to remove most of the water in the film, so that MXene is converted into particles during subsequent high temperature treatment. It was difficult to obtain a membrane similar in structure to Example 4.

Salt rejection tests performed on the membrane showed no salt rejection.

Example 8

The film preparation method similar to Example 4 was adopted, except that the drying time was changed to 24 hours. A film similar in structure to Example 4 was obtained.

The test results of water flux and salt cut-off rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 99.1LMH and the salt cut-off rate is as high as 20°C. Up to 99.9%.

The water flux and salt rejection rate of the membrane obtained by the drying time of 16 hours and 24 hours are almost the same, so the optimized drying time is 16 hours, and it also shows that the membrane can be fully dried in 16 hours without affecting the subsequent process.

Example 9

A membrane preparation method similar to that of Example 4 was adopted, except that the heat treatment temperature was changed to 800°C. A membrane with a structure similar to that of Example 4 was obtained.

The test results of water flux and salt rejection rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 69.1LMH and the salt rejection rate is as high as 20°C. Up to 99.9%.

Example 10

A membrane preparation method similar to that of Example 4 was adopted, except that the heat treatment temperature was changed to 1000°C. A membrane with a structure similar to that of Example 3 was obtained.

The test results of water flux and salt rejection rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 93.2LMH and the salt rejection rate is 93.2LMH under the test condition of 20°C. Up to 99.9%. The treatment temperature has an effect on the sublimation process of chitosan to graphene conversion, as it may affect the water flux of the membrane. In general, the heat treatment temperature reaches 900-1000°C, and the crystallization of graphene reaches the best, so the water flux of the membrane after heat treatment at 900°C and 1000°C is not much different, and the increased part is within the error range . In order to further save energy consumption in the membrane preparation process, the optimized heat treatment temperature was 900 °C.

Example 11

A membrane preparation method similar to that of Example 4 was adopted, except that the heat treatment time was changed to 2 h. A membrane with a structure similar to that of Example 4 was obtained.

The test results of water flux and salt interception rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 89.8LMH and the salt interception rate is as high as 20°C. Up to 99.9%.

Example 12

A membrane preparation method similar to that of Example 4 was adopted, except that the heat treatment time was changed to 4 h. A membrane with a structure similar to that of Example 4 was obtained.

The test results of water flux and salt interception rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 96.8LMH and the salt interception rate is as high as 20°C under the test conditions. Up to 99.9%.

Example 13

A membrane preparation method similar to that of Example 4 was adopted, except that the volume of the precursor solution used for suction filtration to form a membrane was changed to 0.8 mL. A membrane with a structure similar to that of Example 4 was obtained.

The test results of water flux and salt interception rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 130.4LMH and the salt interception rate is as high as 20°C under the test conditions. Up to 99.9%. However, because the film formed under this condition is too thin, the success rate of preparing a film with a perfect structure is low.

Example 14

A membrane preparation method similar to that of Example 4 was adopted, except that the volume of the precursor solution used for suction filtration to form a membrane was changed to 1.5 mL. A membrane with a structure similar to that of Example 4 was obtained.

The test results of water flux and salt interception rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the water flux of the membrane is as high as 67.3LMH and the salt interception rate is as high as 20°C. Up to 99.9%.

Example 15

The same membrane preparation method as in Example 4 was adopted, except that the temperature of the NaCl extract solution, which is the test condition of the membrane performance, was adjusted to 70°C.

The test results of water flux and salt cut-off rate of the membrane show that when 2000mg/L NaCl solution is used as the extraction solution, the membranes prepared with different MXene/chitosan ratios under the test conditions of 70°C The water flux is as high as 230.5-300.8LMH, and the salt interception rate is as high as 99.9%.

Claims (10)

1. A method for preparing a microporous passageway membrane, which is characterized in that: the method comprises the following steps:

a. precursor(s)Preparing a bulk solution: dissolving lithium fluoride in 6-9 mol/L hydrochloric acid solution, introducing inert gas, stirring for 1-2 hr, and adding Ti ₃ AlC ₂ Lithium fluoride, hydrochloric acid solution and Ti ₃ AlC ₂ The ratio of (2) is: 0.5 to 1.5:15-25:0.5 to 1.5, the unit is g/mL/g, the reaction temperature is kept at 20 to 35 ℃ and stirring is continued for 12 to 24 hours under the condition of introducing inert gas; ultrasonically treating the reacted solution for 5-15 min, using deionized water and centrifugal auxiliary cleaning for 3-5 times, wherein the centrifugal speed is 3000-5000 r/min, the centrifugal time is 4-10 min, retaining bottom sediment in the previous 3-5 cleaning processes, adding deionized water, shaking to uniformly disperse sediment, retaining the centrifugal speed of 3000-5000 r/min for 0.5-1.5 h, taking supernatant, and diluting to 60-100 mg/mL to obtain an MXene precursor aqueous solution;

b. taking 0.25-5 mL of acetic acid solution with the mass concentration of 3-5 mg/mL of chitosan, and fully mixing with 5-83 mL of the MXene aqueous solution obtained in the step a to obtain a precursor solution;

c. and (3) deposition: filtering 0.8-1.5mL of precursor solution on a porous substrate by a vacuum filtering method, and then drying for 8-24 hours at room temperature;

d. and (3) heat treatment: placing the membrane which is filtered on the ceramic substrate in a protective atmosphere, and calcining for 2-4 hours at the temperature of 800-1000 ℃;

the microporous channel membrane comprises a porous substrate layer and Ti on the porous substrate layer ₃ C ₂ A graphene composite layer; the Ti is ₃ C ₂ The graphene composite layer consists of an upper graphene layer, a lower graphene layer and Ti sandwiched between the two graphene layers ₃ C ₂ The graphene layer is of a broken piece discontinuous structure and is obtained by layer compounding, and the Ti is ₃ C ₂ The layer is also a broken piece discontinuous structure;

Ti ₃ C ₂ from Ti ₃ AlC ₂ Stripping and removing functional groups introduced by stripping to form a sheet structure; the graphene layer is prepared from chitosan in Ti ₃ C ₂ And carbonizing and crystallizing on the sheet.

2. The method for preparing a microporous passageway membrane according to claim 1, wherein: the mixing in step b is carried out by magnetic stirring.

3. The method for preparing a microporous passageway membrane according to claim 1, wherein: and (c) adding 8-12mL of deionized water into the solution before mixing in the step b.

4. The method for preparing a microporous passageway membrane according to claim 1, wherein: the inert gas in the step a is nitrogen or argon.

5. The method for preparing a microporous passageway membrane according to claim 1, wherein: and c, the porous substrate is a porous alumina ceramic substrate.

6. The method for preparing a microporous passageway membrane according to claim 1, wherein: the protective atmosphere in the step d is nitrogen or argon.

7. The microporous passageway membrane formed by the two-dimensional material prepared by the preparation method according to any one of claims 1 to 6, which is characterized in that: the microporous channel membrane comprises a porous substrate layer and Ti on the porous substrate layer ₃ C ₂ A graphene composite layer; the Ti is ₃ C ₂ The graphene composite layer consists of an upper graphene layer, a lower graphene layer and Ti sandwiched between the two graphene layers ₃ C ₂ The graphene layer is of a broken piece discontinuous structure and is obtained by layer compounding, and the Ti is ₃ C ₂ The layer is also a broken piece discontinuous structure;

Ti ₃ C ₂ from Ti ₃ AlC ₂ Stripping and removing functional groups introduced by stripping to form a sheet structure; the graphene layer is prepared from chitosan in Ti ₃ C ₂ And carbonizing and crystallizing on the sheet.

8. The microporous passageway membrane formed of a two-dimensional material according to claim 7, wherein: the concentration ratio of the two precursors MXene and chitosan is 0.08:27.2-0.83:27.2.

9. The microporous passageway membrane formed of a two-dimensional material according to claim 7, wherein: the porous substrate is a porous alumina ceramic substrate.

10. The microporous passageway membrane formed of a two-dimensional material according to claim 7, wherein: the graphene layer and Ti ₃ C ₂ Intermolecular forces exist between them, stacked together.

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