Preparation and application of Ti3C2Tx-MXene / NH2-ZIF-8 composite film

Abstract

The invention discloses preparation and application of a Ti3C2Tx-MXene / NH2-ZIF-8 composite membrane, the Ti3C2Tx-MXene / NH2-ZIF-8 composite membrane comprises a composite membrane, the composite membrane is composed of an inner supporting layer and an outer layer, the inner supporting layer is Ti3C2Tx-MXene, the outer layer is NH2-ZIF-8, the NH2-ZIF-8 is an ammoniated ZIF-8 thin film, and the Ti3C2Tx-MXene / NH2-ZIF-8 composite membrane is prepared from the inner supporting layer and the outer layer through a hydrothermal method. According to the prepared composite membrane, the membrane selectivity and permeability are improved, the helium flux reaches 306 Barrer, the He / CH4 selectivity and the He / N2 selectivity reach 252.89 and 302.97, and the Ti2C3Tx-MXene / NH2-ZIF-8 composite membrane has excellent plasticizing resistance and the service life.

Description

Technical Field

[0001] The present invention belongs to the field of composite film preparation, and specifically relates to a Ti3C2T x -Preparation and application of MXene / NH2-ZIF-8 composite membrane. Background Art

[0002] Helium plays a vital role in protecting national security and enhancing military capabilities. It is used not only to cool superconducting magnets in military equipment but also as a key component of the breathing gas mixture (containing oxygen and helium) used in deep-diving submarines and submersibles. Currently, industrial-scale helium production is primarily achieved by extracting and purifying it from natural gas. The following are several key technologies for industrial helium extraction: Cryogenic distillation: This technology is widely used in industry, capable of processing large quantities of gas and extracting high-purity helium. However, this process requires expensive cryogenic equipment and consumes significant energy to maintain the required low temperatures. Adsorption separation: This method is popular due to its simple equipment, ease of operation, and customizable adsorbents. However, the capacity and selectivity of the adsorbents may limit their effectiveness in large-scale industrial applications, and regular regeneration is required. Membrane separation: This method is valued for its high efficiency and energy-saving properties. It offers advantages such as simple operation, compact equipment, low energy consumption, and operation at room temperature, reducing environmental impact. By adjusting the membrane material and structure, the separation efficiency and selectivity of different gas mixtures can be improved.

[0003] Gas membrane separation technology is favored for its high efficiency, low energy consumption and environmental friendliness, and is particularly suitable for gas separation processes in energy-intensive industries. However, it still faces some challenges in practical applications, including the "trade-off" effect, low selectivity, and poor stability. Reference [CHEMENGRESDES.2022,181,195-208] reported a mixed matrix membrane (MMMs) based on Pebax-2533 for CO2 / CH4 separation. The ZIF-8-PEI@[P(3)HIm][Tf2N] membrane increased the CO2 permeability by 123%, but the CO2 / CH4 selectivity was only 25. Reference [JMEMBRANESCI.2021.636.19581] reported a mixed matrix membrane (MMMs) based on polymer intrinsic microporosity (PIM-1) for CO2 / N2 separation. The IL@MOF / PIM-5% composite membrane increased the CO2 permeability by 129%, but the CO2 / N2 selectivity was only 29. Patent CN115672062A introduces a graphene-assisted ZIF-8 membrane material for extracting helium, but the material's selectivity for helium in mixtures such as He / N2 and He / CH4 is only 14, and the preparation method is relatively complicated, making it unsuitable for industrialization.

[0004] In view of the above shortcomings, the present invention designs a composite film by combining Ti3C2T x -MXene's excellent mechanical stability and NH2-ZIF-8's efficient gas adsorption capacity have been reported. x -MXene / NH2-ZIF-8 composite film preparation method. This method designs Ti3C2T x -MXene as the inner support layer and NH2-ZIF-8 film as the outer layer. Ti3C2T x -MXene has excellent mechanical stability and a high surface area to volume ratio, which increases the contact area with gas molecules and improves gas separation efficiency, so it can be used as a support layer. x -The π-π stacking structure formed at the MXene interface can enhance the interfacial solubility of NH2-ZIF-8 and improve the Ti3C2T x -MXene / NH2-ZIF-8 composite membrane's anti-plasticization and mechanical stability. This method provides new ideas and methods for membrane separation technology. Summary of the Invention

[0005] In view of the defects and shortcomings of the current process for preparing iron phosphate, the purpose of the present invention is to provide a preparation and application of a Ti3C2Tx-MXene / NH2-ZIF-8 composite membrane. This method can not only obtain battery-grade iron phosphate, but also realize the recycling of nitric acid, reduce the amount of wastewater treatment, and has a simple process flow and low cost, which is conducive to large-scale production.

[0006] In order to achieve the above technical objectives, the present invention provides a Ti3C2T x -Preparation and application of MXene / NH2-ZIF-8 composite membranes, including Ti3C2T x -MXene / NH2-ZIF-8 composite film, the Ti3C2T x -MXene / NH2-ZIF-8 composite membrane consists of an inner support layer and an outer layer, wherein the inner support layer is Ti3C2T x -MXene, the outer layer is NH2-ZIF-8, the NH2-ZIF-8 is an aminated ZIF-8 film, the inner support layer and the outer layer are prepared by hydrothermal method to obtain Ti3C2T x -MXene / NH2-ZIF-8 composite membrane;

[0007] The Ti3C2T x -The preparation method of MXene / NH2-ZIF-8 composite membrane specifically comprises the following steps:

[0008] 1) Ti2C3T x -Preparation of MXene films

[0009] HF is used as solvent and Ti3AlC2MAX is used as solute. A Ti3AlC2MAX solution with a solute / solvent molar ratio of 1 to 5:50 is prepared. The mixed suspension is then etched with magnetic stirring at room temperature. The speed is set to 1000 rpm-3500 rpm. After the etching is completed, the solid product is rinsed with pure water several times until the pH of the cleaning solution reaches 7. The black powder obtained by filtration is then dried in vacuum to obtain bulk Ti2C3T x -MXene;

[0010] Few-layer Ti2C3T x The preparation method of -MXene is as follows: First, the bulk Ti2C3T x -MXene was added to dimethyl sulfoxide (DMSO) solution, Ti2C3T x-MXene and dimethyl sulfoxide (DMSO) mass ratio is 1:50, magnetic stirring is carried out at room temperature, and then the obtained suspension is centrifuged at a speed of 3500rpm-5000rpm for 25min-35min, and the centrifuged product is washed with deionized water. The operation is repeated several times to ensure that DMSO is completely removed. Subsequently, the obtained Ti3C2T x The mixture was evenly dispersed in pure water and ultrasonicated for 6-12 hours under ice bath and argon bubbling protection to obtain a uniform dark green dispersion. The dark green suspension was freeze-dried to successfully obtain a few-layer Ti2C3T x -MXene powder, which was then mixed with ultrapure water to a concentration of 3.0 mg mL -1 -6.0mg·mL -1 The MXene film was prepared on an anodic aluminum oxide (AO) substrate using a vacuum-assisted filtration technique: the AO had a pore size of 0.2 μm to 0.5 μm and a diameter of 35 to 55 mm, and then 3.0 mg mL -1 -6.0mg·mL -1 The MXene solution is poured onto the AO substrate, and then the MXene nanosheets are deposited on the AO using vacuum-assisted filtration. The prepared film is then dried to obtain a MXene film.

[0011] 2) Ti2C3T x Preparation of MXene / ZIF-8 membrane

[0012] 2 g to 4 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) was dissolved in 100 ml to 200 ml of deionized water (DI water) to obtain a zinc nitrate solution. 40 g to 60 g of 2-methylimidazole (Hmim) was dissolved in another 100 ml to 200 ml of DI water to obtain a 2-methylimidazole solution. The two solutions were mixed at room temperature. 2.5 g to 10 g of the MXene film prepared in the first step was added and stirred vigorously. After stirring for 10 to 20 minutes, the synthesized Ti2C3T was collected by centrifugation. x -MXene / ZIF-8 and washed with DI water 3 to 5 times;

[0013] The obtained Ti2C3T x -MXene / ZIF-8 was dried and vacuum activated, and then Ti2C3T was prepared on an anodic aluminum oxide (AO) substrate using vacuum-assisted filtration technology. x -MXene / ZIF-8 membrane: 50mg / ml~100mg / ml Ti2C3T x-MXene / ZIF-8 mixed solution; prepare AO with a diameter of 35 mm to 55 mm and a pore size of 0.2 μm to 0.5 μm; then add 50 mg / ml to 100 mg / ml of Ti2C3T x -MXene / ZIF-8 mixed solution is poured on the AO substrate, and then MXene nanosheets are deposited on the AO substrate by vacuum assisted filtration. Finally, the prepared film is dried, and then Ti2C3T x -MXene / ZIF-8 film;

[0014] 3) Ti2C3T x Preparation of MXene / NH2-ZIF-8 membrane

[0015] 2 g to 4 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) was dissolved in 100 ml to 200 ml of deionized water (DI water) to obtain a zinc nitrate solution. 40 g to 60 g of 2-methylimidazole (Hmim) was dissolved in another 100 ml to 200 ml of DI water to obtain a 2-methylimidazole solution. The two solutions were mixed at room temperature. 2.5 g to 10 g of the MXene film prepared in the first step was added and stirred vigorously. After stirring for 10 to 20 minutes, the synthesized Ti2C3T was collected by centrifugation. x -MXene / ZIF-8 and washed with DI water 3 to 5 times;

[0016] The obtained Ti2C3T x -MXene / ZIF-8 was dried at 40℃~50℃ for 12h~24h, then vacuum activated at 100℃~150℃ for 1h~2h, and then Ti2C3T was prepared on an anodic aluminum oxide (AO) substrate using vacuum assisted filtration technology. x -MXene / ZIF-8 membrane: 50mg / ml~100mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution; prepare AO with a diameter of 35 mm to 55 mm and a pore size of 0.2 μm to 0.5 μm; then add 50 mg / ml to 100 mg / ml of Ti2C3T x -MXene / ZIF-8 mixed solution is poured on the AO substrate, and then MXene nanosheets are deposited on the AO substrate by vacuum assisted filtration. Finally, the prepared film is dried at 70℃ to 90℃ for 24h to 48h, and then Ti2C3T x -MXene / ZIF-8 film;

[0017] The dried Ti2C3T x-MXene / ZIF-8 film adsorbs in ethylenediamine saturated vapor for 3h~5h, Ti2C3T x The MXene / NH2-ZIF-8 film was rinsed with acetone several times and then dried in air at 100-120°C overnight to obtain Ti2C3T x -MXene / NH2-ZIF-8 membrane.

[0018] As a preferred solution, in steps 1, 2, and 3, the entire Ti2C3T x -MXene films and Ti2C3T x -Argon (Ar) was used as the protective gas during the preparation of MXene / NH2-ZIF-8 membrane.

[0019] As a preferred solution, the magnetic stirring time at room temperature in step 1 is 24h-48h, the black powder in step 1 is vacuum dried at 60℃-80℃ for 12h-15h, and the film prepared in step 1 is dried at 70℃ to 90℃ for 24 hours.

[0020] As a preferred solution, the film prepared in step 2 is dried at 70° C. to 90° C. for 24 h to 48 h.

[0021] As a preferred solution, in step 2, Ti2C3T x -MXene / ZIF-8 was dried at 40°C to 50°C for 12h to 24h and vacuum activated at 100°C to 150°C for 1h to 2h.

[0022] As a preferred solution, the centrifugal speed in step 2 is 5000 rpm to 9000 rpm and the centrifugal time is 5 minutes to 10 minutes.

[0023] As a preferred solution, the centrifugal speed in step 3 is 5000 rpm to 9000 rpm and the centrifugal time is 5 minutes to 10 minutes.

[0024] Compared with the existing technology, the technical solution of the present invention brings the following beneficial technical effects:

[0025] It can be seen from the data in Table 1 that the addition of Ti2C3T x -MXene NH2-ZIF-8 composite membrane has high flux and selectivity, with helium flux reaching 306GPU, He / CH4, He / N2 selectivity reaching 302.97, 25.89. x -MXene NH2-ZIF-8 has a low flux of only 100 GPU and a He / CH4 selectivity of only 101.01, which indicates that the few-layer Ti3C2T x-MXene can effectively transport gases and has excellent gas selectivity. However, when using ZIF-8, the helium flux is only 79GPU and the He / CH4 selectivity is only 80.61. This is because the unaminated ZIF-8 has a low gas adsorption capacity. Figure 1 It was found that with the increase of feed pressure, He / CH4 selectivity decreased significantly (the decrease was 5.77), while Figure 2 It was found that the He / CH4 selectivity was not significantly different (the decrease was 2.97), which indicated that the few-layer Ti3C2T x The introduction of -MXene gives NH2-ZIF-8 excellent anti-plasticization performance. Figure 3 It was found that Ti2C3T x -In the life test of MXene / He / CH4 selectivity, the He flux decay rate is only 6.3%, which is much lower than that without Ti2C3T x -MXene (attenuation rate: 27.7%);

[0026] The present invention prepares Ti2C3T x -MXene / NH2-ZIF-8 composite membrane improves membrane selectivity and permeability, with a helium flux of 306 Barrer and He / CH4 and He / N2 selectivities of 252.89 and 302.97 respectively;

[0027] Ti2C3T x -MXene / NH2-ZIF-8 composite film has excellent plasticization resistance and lifespan. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a data diagram of the anti-plasticization performance of the composite film of Example 1;

[0029] Figure 2 This is a data diagram of the anti-plasticization performance of the composite film of Comparative Example 2;

[0030] Figure 3 This is a graph showing the life test data of Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] Example 1

[0033] This embodiment provides a Ti2C3Tx -MXene / NH2-ZIF-8 composite membrane preparation method, the preparation steps are as follows:

[0034] 1. Ti2C3T x -Preparation of MXene films

[0035] 3g Ti3AlC2 powder was slowly added to 30mL hydrofluoric acid (49%) in several times, and then the mixed suspension was magnetically stirred at room temperature for 48h for etching, and the speed was set to 3500rpm. After the etching was completed, the solid product was rinsed with pure water several times until the pH of the cleaning solution was >6, and then the obtained black powder was vacuum dried at 60℃ for 12h to obtain bulk Ti2C3T x -MXene. Few-layer Ti2C3T x -MXene preparation: First, bulk Ti2C3T x -MXene was added to dimethyl sulfoxide (DMSO) solution with a mass ratio of 1:50. The mixture was magnetically stirred at room temperature for 24 h. Then, the obtained suspension was centrifuged at 3500 rpm for 25 min, and the centrifuged product was washed with deionized water. The operation was repeated 5 times to ensure that DMSO was completely removed. Subsequently, the obtained Ti2C3T x -MXene was evenly dispersed in pure water and ultrasonicated for 6 hours under ice bath and argon bubbling protection. The dark green suspension was freeze-dried to successfully obtain few-layer Ti2C3T x -MXene powder. Subsequently, the powder was mixed with ultrapure water to a concentration of 3.33 mg·mL -1 The MXene membrane was then prepared on an anodic aluminum oxide (AO) substrate using vacuum-assisted filtration: the AO had a pore size of 0.2 μm and a diameter of 35 mm, and 3.33 mg mL -1 A MXene solution is poured onto an AO substrate, followed by vacuum-assisted filtration to deposit MXene nanosheets onto the AO. The resulting membrane is then dried at 70°C for 24 hours to obtain a MXene thin film. Argon (Ar) serves as the protective gas throughout the membrane preparation process.

[0036] Ti2C3T x -Preparation of MXene / ZIF-8 thin films

[0037] 2.34 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) was dissolved in 160 ml of deionized water (DI water) to obtain a zinc nitrate solution. 45.40 g of 2-methylimidazole (Hmim) was dissolved in another 160 ml of DI water to obtain a 2-methylimidazole solution. The two solutions were mixed and stirred vigorously at room temperature. At the same time, 5 g of the MXene film prepared in the first step was added. After stirring for 20 minutes, the synthesized Ti2C3T was collected by centrifugation (9000 rpm, 10 minutes). x -MXene / ZIF-8 and washed with DI water three times. Then, a vacuum-assisted filtration technique was used to prepare Ti2C3T on an anodic aluminum oxide (AO) substrate. x -MXene / ZIF-8 membrane: 50 mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution; prepare 35 mm diameter AO with a pore size of 0.2 μm; then add 50 mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution was poured onto the AO substrate, and then MXene nanosheets were deposited on the AO using vacuum assisted filtration. Finally, the prepared film was dried at 70 ° C for 24 h, and then Ti2C3T x -MXene / ZIF-8 thin film. Argon (Ar) was used as the protective gas throughout the film preparation process.

[0038] Ti2C3T x Preparation of MXene / NH2-ZIF-8 composite membrane

[0039] 2.34 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) was dissolved in 160 ml of deionized water (DI water) to obtain a zinc nitrate solution. 45.40 g of 2-methylimidazole (Hmim) was dissolved in another 160 ml of DI water to obtain a 2-methylimidazole solution. The two solutions were mixed and stirred vigorously at room temperature. At the same time, 5 g of the MXene film prepared in the first step was added. After stirring for 20 minutes, the synthesized Ti2C3T was collected by centrifugation (9000 rpm, 10 minutes). x -MXene / ZIF-8 and washed with DI water three times. Then, a vacuum-assisted filtration technique was used to prepare Ti2C3T on an alumina (AO) substrate. x -MXene / ZIF-8 membrane: 50 mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution; prepare 35 mm diameter AO with a pore size of 0.2 μm; then add 50 mg / ml Ti2C3T x-MXene / ZIF-8 mixed solution was poured onto the AO substrate, and then MXene nanosheets were deposited on the AO using vacuum assisted filtration. Finally, the prepared film was dried at 70 ° C for 24 h, and then Ti2C3T x -MXene / ZIF-8 film. During the whole film preparation process, argon (Ar) was used as the protective gas. x -MXene / ZIF-8 film was adsorbed in ethylenediamine saturated vapor for 3 h, Ti2C3T x The MXene / NH2-ZIF-8 film was rinsed with acetone several times and then dried in air at 100-120°C overnight to obtain Ti2C3T x -MXene / NH2-ZIF-8 membrane.

[0040] Example 2

[0041] This embodiment provides a Ti2C3T x -MXene / NH2-ZIF-8 composite membrane preparation method, the preparation steps are as follows:

[0042] 1. Ti2C3T x -Preparation of MXene films

[0043] 3g Ti3AlC2 powder was slowly added to 30mL hydrofluoric acid (49%) in several times, and then the mixed suspension was magnetically stirred at room temperature for 48h for etching, and the speed was set to 3500rpm. After the etching was completed, the solid product was rinsed with pure water several times until the pH of the cleaning solution was >6, and then the obtained black powder was vacuum dried at 60℃ for 12h to obtain bulk Ti2C3T x -MXene. Few-layer Ti2C3T x -MXene preparation: First, bulk Ti2C3T x -MXene was added to dimethyl sulfoxide (DMSO) solution with a mass ratio of 1:50. The mixture was magnetically stirred at room temperature for 24 h. Then, the obtained suspension was centrifuged at 3500 rpm for 25 min, and the centrifuged product was washed with deionized water. The operation was repeated 5 times to ensure that DMSO was completely removed. Subsequently, the obtained Ti2C3T x -MXene was evenly dispersed in pure water and ultrasonicated for 6 hours under ice bath and argon bubbling protection. The dark green suspension was freeze-dried to successfully obtain few-layer Ti2C3T x -MXene powder. Subsequently, the powder was mixed with ultrapure water to a concentration of 3.33 mg·mL -1The MXene membrane was then prepared on an anodic aluminum oxide (AO) substrate using vacuum-assisted filtration: the AO had a pore size of 0.2 μm and a diameter of 35 mm, and 3.33 mg mL -1 A MXene solution is poured onto an AO substrate, followed by vacuum-assisted filtration to deposit MXene nanosheets onto the AO. The resulting membrane is then dried at 70°C for 24 hours to obtain a MXene thin film. Argon (Ar) serves as the protective gas throughout the membrane preparation process.

[0044] Ti2C3T x -Preparation of MXene / ZIF-8 thin films

[0045] 2.34 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) was dissolved in 160 ml of deionized water (DI water) to obtain a zinc nitrate solution. 45.40 g of 2-methylimidazole (Hmim) was dissolved in another 160 ml of DI water to obtain a 2-methylimidazole solution. The two solutions were mixed and stirred vigorously at room temperature. At the same time, 5 g of the MXene film prepared in the first step was added. After stirring for 20 minutes, the synthesized Ti2C3T was collected by centrifugation (9000 rpm, 10 minutes). x -MXene / ZIF-8 and washed with DI water three times. Then, a vacuum-assisted filtration technique was used to prepare Ti2C3T on an anodic aluminum oxide (AO) substrate. x -MXene / ZIF-8 membrane: 50 mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution; prepare 35 mm diameter AO with a pore size of 0.2 μm; then add 50 mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution was poured onto the AO substrate, and then MXene nanosheets were deposited on the AO using vacuum assisted filtration. Finally, the prepared film was dried at 70 ° C for 24 h, and then Ti2C3T x -MXene / ZIF-8 thin film. Argon (Ar) was used as the protective gas throughout the film preparation process.

[0046] Example 3

[0047] This embodiment provides a Ti2C3T x -MXene / NH2-ZIF-8 composite membrane preparation method, the preparation steps are as follows:

[0048] 1. Ti2C3T x -Preparation of MXene films

[0049] 3g Ti3AlC2 powder was slowly added to 30mL hydrofluoric acid (49%) in several times, and then the mixed suspension was magnetically stirred at room temperature for 48h for etching, and the speed was set to 3500rpm. After the etching was completed, the solid product was rinsed with pure water several times until the pH of the cleaning solution was >6, and then the obtained black powder was vacuum dried at 60℃ for 12h to obtain bulk Ti2C3T x -MXene. Few-layer Ti2C3T x -MXene preparation: First, bulk Ti2C3T x -MXene was added to dimethyl sulfoxide (DMSO) solution with a mass ratio of 1:50. The mixture was magnetically stirred at room temperature for 24 h. Then, the obtained suspension was centrifuged at 3500 rpm for 25 min, and the centrifuged product was washed with deionized water. The operation was repeated 5 times to ensure that DMSO was completely removed. Subsequently, the obtained Ti2C3T x -MXene was evenly dispersed in pure water and ultrasonicated for 6 hours under ice bath and argon bubbling protection. The dark green suspension was freeze-dried to successfully obtain few-layer Ti2C3T x -MXene powder. Subsequently, the powder was mixed with ultrapure water to a concentration of 3.33 mg·mL -1 The MXene membrane was then prepared on an anodic aluminum oxide (AO) substrate using vacuum-assisted filtration: the AO had a pore size of 0.2 μm and a diameter of 35 mm, and 3.33 mg mL -1 A MXene solution is poured onto an AO substrate, followed by vacuum-assisted filtration to deposit MXene nanosheets onto the AO. The resulting membrane is then dried at 70°C for 24 hours to obtain a MXene thin film. Argon (Ar) serves as the protective gas throughout the membrane preparation process.

[0050] Ti2C3T x -Preparation of MXene / ZIF-8 thin films

[0051] 2.34 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) was dissolved in 160 ml of deionized water (DI water) to obtain a zinc nitrate solution. 45.40 g of 2-methylimidazole (Hmim) was dissolved in another 160 ml of DI water to obtain a 2-methylimidazole solution. The two solutions were mixed and stirred vigorously at room temperature. At the same time, 2.5 g of the MXene film prepared in the first step was added. After stirring for 20 minutes, the synthesized Ti2C3T was collected by centrifugation (9000 rpm, 10 minutes). x -MXene / ZIF-8 and washed with DI water three times. Then, a vacuum-assisted filtration technique was used to prepare Ti2C3T on an anodic aluminum oxide (AO) substrate.x -MXene / ZIF-8 membrane: 50 mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution; prepare 35 mm diameter AO with a pore size of 0.2 μm; then add 50 mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution was poured onto the AO substrate, and then MXene nanosheets were deposited on the AO using vacuum assisted filtration. Finally, the prepared film was dried at 70 ° C for 24 h, and then Ti2C3T x -MXene / ZIF-8 thin film. Argon (Ar) was used as the protective gas throughout the film preparation process.

[0052] Ti2C3T x Preparation of MXene / NH2-ZIF-8 composite membrane

[0053] 2.34 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) was dissolved in 160 ml of deionized water (DI water) to obtain a zinc nitrate solution. 45.40 g of 2-methylimidazole (Hmim) was dissolved in another 160 ml of DI water to obtain a 2-methylimidazole solution. The two solutions were mixed and stirred vigorously at room temperature. At the same time, 2.5 g of the MXene film prepared in the first step was added. After stirring for 20 minutes, the synthesized Ti2C3T was collected by centrifugation (9000 rpm, 10 minutes). x -MXene / ZIF-8 and washed with DI water three times. Then, a vacuum-assisted filtration technique was used to prepare Ti2C3T on an alumina (AO) substrate. x -MXene / ZIF-8 membrane: 50 mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution; prepare 35 mm diameter AO with a pore size of 0.2 μm; then add 50 mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution was poured onto the AO substrate, and then MXene nanosheets were deposited on the AO using vacuum assisted filtration. Finally, the prepared film was dried at 70 ° C for 24 h, and then Ti2C3T x -MXene / ZIF-8 film. During the whole film preparation process, argon (Ar) was used as the protective gas. x -MXene / ZIF-8 film was adsorbed in ethylenediamine saturated vapor for 3 h, Ti2C3T x The MXene / NH2-ZIF-8 film was rinsed with acetone several times and then dried in air at 100-120°C overnight to obtain Ti2C3T x-MXene / NH2-ZIF-8 membrane.

[0054] Comparative Example 1

[0055] The difference between this comparative example and Example 1 is that no Ti3C2T x -MXene film.

[0056] Comparative Example 2

[0057] The difference between this comparative example and Example 1 is that 10g Ti3C2T x -MXene film.

[0058] Ti2C3T prepared in the examples and comparative examples x -MXene / NH2-ZIF-8 composite membrane gas separation performance test is as follows:

[0059] The Ti2C3T prepared in Examples 1-3 and Comparative Examples 1-2 x Cutting of MXene / NH2-ZIF-8 composite membranes. Testing was performed at a pressure of 0.4 MPa and room temperature, with argon purging on both the retentate and permeate sides. Test gases included CH4, He, and N2. The test results are shown in Table 1.

[0060] Ti2C3T in Table 1 x -Gas separation performance of MXene / NH2-ZIF-8 composite membrane

[0061]

[0062] Figure 1 and Figure 2 The few-layer Ti2C3T prepared in Example 1 and Comparative Example 2 x -Anti-plasticization properties of MXene / NH2-ZIF-8 composite films;

[0063] Figure 3 Respectively represent the few-layer Ti2C3T prepared in Example 1 and Comparative Example 1 x -The separation He life test of MXene / NH2-ZIF-8 composite membrane was carried out, using ternary mixed gases He / CO2 / CH4 and He / CO2 / N2 as feed gases, and testing its life stability for 260 hours at a pressure of 0.4 MPa.

[0064] It can be seen from the data in Table 1 that the addition of Ti2C3T x -MXene NH2-ZIF-8 composite membrane has high flux and selectivity, with helium flux reaching 306GPU, He / CH4, He / N2 selectivity reaching 302.97, 25.89. x-MXene NH2-ZIF-8 has a low flux of only 100 GPU and a He / CH4 selectivity of only 101.01, which indicates that the few-layer Ti3C2T x -MXene can effectively transport gases and has excellent gas selectivity. However, when using ZIF-8, the helium flux is only 79GPU and the He / CH4 selectivity is only 80.61. This is because the unaminated ZIF-8 has a low gas adsorption capacity. Figure 1 It was found that with the increase of feed pressure, He / CH4 selectivity decreased significantly (the decrease was 5.77), while Figure 2 It was found that the He / CH4 selectivity was not significantly different (the decrease was 2.97), which indicated that the few-layer Ti3C2T x The introduction of -MXene gives NH2-ZIF-8 excellent anti-plasticization performance. Figure 3 It was found that Ti2C3T x -In the life test of MXene / He / CH4 selectivity, the He flux decay rate is only 6.3%, which is much lower than that without Ti2C3T x -MXene (attenuation rate: 27.7%).

[0065] The present invention prepares Ti2C3T x -MXene / NH2-ZIF-8 composite membrane improves membrane selectivity and permeability, with helium flux reaching 306 Barrer, and He / CH4 and He / N2 selectivities reaching 252.89 and 302.97.

[0066] Ti2C3T x -MXene / NH2-ZIF-8 composite film has excellent plasticization resistance and lifespan.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A Ti3C2T x - Preparation and application of MXene / NH2-ZIF-8 composite membrane, characterized by: Including Ti3C2T x -MXene / NH2-ZIF-8 composite film, the Ti3C2T x -MXene / NH2-ZIF-8 composite membrane consists of an inner support layer and an outer layer, wherein the inner support layer is Ti3C2T x -MXene, the outer layer is NH2-ZIF-8, the NH2-ZIF-8 is an aminated ZIF-8 film, the inner support layer and the outer layer are prepared by hydrothermal method to obtain Ti3C2T x -MXene / NH2-ZIF-8 composite membrane; The Ti3C2T x -The preparation method of MXene / NH2-ZIF-8 composite membrane specifically comprises the following steps: 1) Ti2C3T x -Preparation of MXene films HF is used as solvent and Ti3AlC2MAX is used as solute. A Ti3AlC2MAX solution with a solute / solvent molar ratio of 1 to 5:50 is prepared. The mixed suspension is then etched with magnetic stirring at room temperature. The speed is set to 1000 rpm-3500 rpm. After the etching is completed, the solid product is rinsed with pure water several times until the pH of the cleaning solution reaches 7. The black powder obtained by filtration is then dried in vacuum to obtain bulk Ti2C3T x -MXene; Few-layer Ti2C3T x The preparation method of -MXene is as follows: First, the bulk Ti2C3T x -MXene was added to dimethyl sulfoxide (DMSO) solution, Ti2C3T x -MXene and dimethyl sulfoxide (DMSO) mass ratio is 1:50, magnetic stirring is carried out at room temperature, and then the obtained suspension is centrifuged at a speed of 3500rpm-5000rpm for 25min-35min, and the centrifuged product is washed with deionized water. The operation is repeated several times to ensure that DMSO is completely removed. Subsequently, the obtained Ti3C2T x The mixture was evenly dispersed in pure water and ultrasonicated for 6-12 hours under ice bath and argon bubbling protection to obtain a uniform dark green dispersion. The dark green suspension was freeze-dried to successfully obtain a few-layer Ti2C3T x -MXene powder, which was then mixed with ultrapure water to a concentration of 3.0 mg mL -1 -6.0mg·mL -1 The MXene film was prepared on an anodic aluminum oxide (AO) substrate using a vacuum-assisted filtration technique: the AO had a pore size of 0.2 μm to 0.5 μm and a diameter of 35 to 55 mm, and then 3.0 mg mL -1 -6.0mg·mL -1 The MXene solution is poured onto the AO substrate, and then the MXene nanosheets are deposited on the AO using vacuum-assisted filtration. The prepared film is then dried to obtain a MXene film. 2) Ti2C3T x Preparation of MXene / ZIF-8 membrane 2 g to 4 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) was dissolved in 100 ml to 200 ml of deionized water (DI water) to obtain a zinc nitrate solution. 40 g to 60 g of 2-methylimidazole (Hmim) was dissolved in another 100 ml to 200 ml of DI water to obtain a 2-methylimidazole solution. The two solutions were mixed at room temperature. 2.5 g to 10 g of the MXene film prepared in the first step was added and stirred vigorously. After stirring for 10 to 20 minutes, the synthesized Ti2C3T was collected by centrifugation. x -MXene / ZIF-8 and washed with DI water 3 to 5 times; The obtained Ti2C3T x -MXene / ZIF-8 was dried and vacuum activated, and then Ti2C3T was prepared on an anodic aluminum oxide (AO) substrate using vacuum-assisted filtration technology. x -MXene / ZIF-8 membrane: 50mg / ml~100mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution; prepare AO with a diameter of 35 mm to 55 mm and a pore size of 0.2 μm to 0.5 μm; then add 50 mg / ml to 100 mg / ml of Ti2C3T x -MXene / ZIF-8 mixed solution is poured on the AO substrate, and then MXene nanosheets are deposited on the AO substrate by vacuum assisted filtration. Finally, the prepared film is dried, and then Ti2C3T x -MXene / ZIF-8 film; 3) Ti2C3T x Preparation of MXene / NH2-ZIF-8 membrane 2 g to 4 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) was dissolved in 100 ml to 200 ml of deionized water (DI water) to obtain a zinc nitrate solution. 40 g to 60 g of 2-methylimidazole (Hmim) was dissolved in another 100 ml to 200 ml of DI water to obtain a 2-methylimidazole solution. The two solutions were mixed at room temperature. 2.5 g to 10 g of the MXene film prepared in the first step was added and stirred vigorously. After stirring for 10 to 20 minutes, the synthesized Ti2C3T was collected by centrifugation. x -MXene / ZIF-8 and washed with DI water 3 to 5 times; The obtained Ti2C3T x -MXene / ZIF-8 was dried at 40℃~50℃ for 12h~24h, then vacuum activated at 100℃~150℃ for 1h~2h, and then Ti2C3T was prepared on an anodic aluminum oxide (AO) substrate using vacuum assisted filtration technology. x -MXene / ZIF-8 membrane: 50mg / ml~100mg / ml Ti2C3T x -MXene / ZIF-8 mixed solution; prepare AO with a diameter of 35 mm to 55 mm and a pore size of 0.2 μm to 0.5 μm; then add 50 mg / ml to 100 mg / ml of Ti2C3T x -MXene / ZIF-8 mixed solution is poured on the AO substrate, and then MXene nanosheets are deposited on the AO substrate by vacuum assisted filtration. Finally, the prepared film is dried at 70℃ to 90℃ for 24h to 48h, and then Ti2C3T x -MXene / ZIF-8 film; The dried Ti2C3T x -MXene / ZIF-8 film adsorbs in ethylenediamine saturated vapor for 3h~5h, Ti2C3T x The MXene / NH2-ZIF-8 film was rinsed with acetone several times and then dried in air at 100-120°C overnight to obtain Ti2C3T x -MXene / NH2-ZIF-8 membrane.

2. A Ti3C2T according to claim 1 x - Preparation and application of MXene / NH2-ZIF-8 composite membrane, characterized by: In steps 1, 2, and 3, the entire Ti2C3T x -MXene films and Ti2C3T x -Argon (Ar) was used as the protective gas during the preparation of MXene / NH2-ZIF-8 membrane.

3. A Ti3C2T according to claim 1 x - Preparation and application of MXene / NH2-ZIF-8 composite membrane, characterized by: The magnetic stirring time at room temperature in step 1 is 24-48 hours, the black powder in step 1 is vacuum dried at 60-80°C for 12-15 hours, and the film prepared in step 1 is dried at 70-90°C for 24 hours.

4. A Ti3C2T according to claim 1 x - Preparation and application of MXene / NH2-ZIF-8 composite membrane, characterized by: The film prepared in step 2 is dried at 70° C. to 90° C. for 24 to 48 hours.

5. A Ti3C2T according to claim 1 x - Preparation and application of MXene / NH2-ZIF-8 composite membrane, characterized by: In step 2, Ti2C3T x -MXene / ZIF-8 was dried at 40°C to 50°C for 12h to 24h and vacuum activated at 100°C to 150°C for 1h to 2h.

6. A Ti3C2T according to claim 1 x - Preparation and application of MXene / NH2-ZIF-8 composite membrane, characterized by: In step 2, the centrifugal speed is 5000 rpm to 9000 rpm and the centrifugal time is 5 minutes to 10 minutes.

7. A Ti3C2T according to claim 1 x - Preparation and application of MXene / NH2-ZIF-8 composite membrane, characterized by: In step 3, the centrifugal speed is 5000 rpm to 9000 rpm and the centrifugal time is 5 minutes to 10 minutes.

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