CN114367199A - Method for preparing MOF film by in-situ phase inversion method and application - Google Patents

Abstract

The invention discloses a method and application for preparing a MOF film by an in-situ phase inversion method. In the process, factors related to seed loading, formic acid amount, synthesis time and synthesis temperature are investigated on the surface density, thickness and surface roughness of the MOF film. degree and membrane hydrophilicity, while applying it to ethanol/water and butanol/water separations. The invention successfully prepares an ultra-thin MOF membrane, has excellent separation performance and good long-term stability, and is a very potential separation technology.

Description

Method and application of MOF thin film prepared by in situ phase inversion method

technical field

The invention belongs to the field of new materials, and in particular relates to a method and application for preparing a MOF film by an in-situ phase inversion method.

Background technique

As an alternative technology for rectification and separation, pervaporation technology has been developed as a practical technology that can be accepted in industry. consumption plays an important role, proving the reliability and competitiveness of this new membrane technology.

Traditional pervaporation membrane materials include polymer membranes, ceramic membranes, zeolite membranes, and the like. Polymer membranes are easy to prepare and have strong mechanical strength, and have been widely used in industrial gas separation, reverse osmosis and other processes. Some polymer membrane materials have poor chemical stability and thermal stability in pervaporation applications. Inorganic membranes, especially zeolite membranes, have been widely used in the dehydration of organic matter, but their structural brittleness limits their application. Metal-organic framework (MOF) membranes have a general topology and precisely tunable nano-channel structure, and at the same time have a robust framework structure. Therefore, MOF membranes are a promising separation material. Metal-organic frameworks (MOFs) are a class of materials with periodic network structures formed by coordination interactions between organic ligands and metal centers. Compared with traditional inorganic porous materials, MOFs have the advantages of larger specific surface area, higher porosity, and adjustable structure and pore height.

At present, the common preparation methods of metal-organic framework films include in-situ hydrothermal synthesis, secondary growth method, etc. These methods are restricted by some factors to varying degrees, such as: a large number of raw material solutions, the influence of membrane assembly methods, etc. The invention realizes the preparation of ultra-thin MOF film materials through the transformation of the original flavor of the metal-organic framework material under the action of steam assistance, and the prepared MOF film exhibits excellent pervaporation performance.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to prepare a MOF film with ultra-thin thickness by in-situ phase inversion technology and its application.

The technical scheme of the present invention is a method for preparing MOF film by an in-situ phase inversion method, and the main steps are:

(1) Preparation of NU-906 particles;

(2) after the surface of the self-made silica carrier is smoothed with sandpaper, 50nm silica particles are coated and calcined at 550° C. for 5h to obtain a silica carrier with a smooth surface;

(3) Disperse the prepared NU-906 seed crystal in a solvent, and assemble it on the modified silica carrier by wet coating to form a dense NU-906 layer, ready for use;

(4) The carrier loaded with NU-906 particles is placed in a PTFE liner with a scaffold, formic acid is added, and the time and temperature are controlled, so that the NU-906 particles can be transformed into a dense MOF film by in-situ phase transformation, and the reaction is completed. Then, the obtained MOF film was immersed in acetone and stored for later use;

(5) Using the self-assembled device to evaluate the permeability of the MOF film, and to evaluate the long-term stability of the film;

(6) SEM characterizes the surface morphology and thickness of the MOF film, XRD reflects the orientation of the MOF film, AFM observes the surface roughness of the MOF film, and the water contact angle tests the hydrophilicity of the MOF film at different times, which further illustrates the orientation of the MOF film. Structural characteristics and separation properties;

Described step (3) NU-906 load is 5-500mg/cm ² ;

The reaction temperature of the MOF film in the step (4) is 25-150°C;

The reaction time of the step (4) MOF film is 2-48h;

The amount of formic acid in the step (4) is 0.08-2000 μL/mg NU-906.

The step (3) solvent includes N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, water, lower alkanol (C1-C6), acetonitrile , acetone or ethyl acetate.

The preparation method of the MOF film in the step (4) is in-situ phase inversion.

In the step (5), the penetration evaluation system is 20wt%-95wt% ethanol/water, operating temperature is 20-120°C; 20wt%-95wt% butanol/water, operating temperature is 20-120°C.

The preparation of NU-906 particles in the present invention includes the following steps: liquid A: dissolve 58.5 mg of zirconium chloride and 24 mg of benzoic acid in 1.8 mL of N,N-dimethylformamide, heat at 80° C. for 1 hour, and cool to room temperature; B Solution: 36mg of 1,4-dibromo-2,3,5,6-tetracarboxyphenyl substituted benzene was dissolved in 1.8mL of N,N-dimethylformamide; the prepared solution A, B and 288mg of benzene were dissolved Formic acid is mixed evenly, heated at 100°C for 2-72h to obtain white powdery NU-906 granules, which are ready for use.

The second technical solution of the present invention is to use the in-situ phase inversion method prepared by the aforementioned method to prepare the MOF film and apply it to the separation of ethanol/water and butanol/water.

Advantages of the present invention:

The present invention successfully prepares the MOF film by the in-situ phase inversion method, and the preparation method is simple and quick, and does not need to add additional chemical reagents. In separation applications, MOF membranes have a separation factor of 600 for ethanol/water and a flux of 2.5kg/(m ² ·h), and a separation factor of 6000 for butanol/water with a flux of 3.8kg/(m ² ·h) h). The MOF film prepared by the invention has ultra-thin thickness, excellent separation performance and good long-term stability, and is a very potential separation technology.

Description of drawings

Figure 1: XRD patterns of MOF films prepared after reaction at 100 °C for 24 h when the loading amount was 250 mg/cm ² and the amount of formic acid was 2 μL/mg NU-906.

Figure 2: Surface images of MOF membranes prepared after 100 °C reaction for 24 h when the loading amount was 250 mg/cm ² and the amount of formic acid was 2 μL/mg NU-906.

Figure 3: Cross-sectional view of the MOF film prepared after reaction at 100 °C for 24 h when the loading amount was 250 mg/cm ² and the amount of formic acid was 2 μL/mg NU-906.

Figure 4: AFM image of MOF film prepared after 100°C reaction for 24h when the loading amount was 250 mg/cm ² and the amount of formic acid was 2 μL/mg NU-906.

Figure 5: The water contact angle diagram of the MOF film prepared after reaction at 100 °C for 24 h when the loading amount was 250 mg/cm ² and the amount of formic acid was 2 μL/mg NU-906.

Detailed ways

The present invention will be further described below with reference to specific embodiments.

For the preparation of NU-906 seeds of the present invention, refer to: Phase Transitions in Metal-OrganicFrameworks Directly Monitored through In Situ Variable Temperature Liquid-Cell Transmission Electron Microscopy and In Situ Xray Diffraction[J]. Journal of the American Chemical Society, 2020, 142(10 ): 4609-4615.

Embodiment 1:

(1) Liquid A: dissolve 58.5 mg of zirconium chloride and 24 mg of benzoic acid in 1.8 mL of N,N-dimethylformamide, heat at 80°C for 1 h, and cool to room temperature; liquid B: 36 mg of 1,4-dibromo -2,3,5,6-Tetracarboxyphenyl-substituted benzene was dissolved in 1.8mL N,N-dimethylformamide; the prepared solution A, B and 288mg benzoic acid were mixed uniformly, heated at 100°C for 2- 72h to obtain white powdery NU-906 granules, ready for use;

(2) after the surface of the self-made silica carrier is smoothed with sandpaper, 50nm silica particles are coated and calcined at 550° C. for 5h to obtain a silica carrier with a smooth surface;

(3) Disperse 2.5 mg of NU-906 seed crystals in 2.6 mL of N,N-dimethylformamide so that the single-chip loading is 5 mg/cm ² , and assemble on the modified silica carrier by wet coating A dense NU-906 layer is formed on it, ready for use;

(4) The carrier pre-coated with NU-906 is placed in a PTFE lining with a stent, and the synthesis time, synthesis temperature and amount of formic acid are controlled, and the formic acid vapor assists the NU-906 particles to generate dense MOF film, after the reaction is completed, the obtained MOF film is soaked in acetone and stored for later use;

(5) Using the self-assembled device to evaluate the permeability of the MOF film, and to evaluate the long-term stability of the film;

(6) the preparation method of the MOF film is in-situ phase inversion;

(7) the synthesis temperature of described MOF film is 25-150 ^℃ ;

(8) the synthesis time of the MOF film is 2-48h;

(9) the amount of formic acid in the MOF membrane is 0.08-2000 μL/mg NU-906;

(10) The penetration evaluation system is 20wt%-95wt% ethanol/water, operating temperature is 20-120 ^°C ; 20wt%-95wt% butanol/water, operating temperature is 20-120 ^°C .

(11) When the amount of formic acid was 2 μL/mg NU-906, the separation factor for 90wt% ethanol/water was 390 and the flux was 3.8 kg/(m ² ·h) for the MOF membrane prepared after reaction at 100 °C for 24 h; The 90 wt% butanol/water separation factor was 4020 and the flux was 2.3 kg/(m ² ·h).

(12) When the amount of formic acid was 2 μL/mg NU-906, the film thickness was 130 nm, the film roughness was 8.9 nm, and the water contact angle was 65° after 100 °C reaction for 24 h.

Embodiment 2:

(1) Liquid A: dissolve 58.5 mg of zirconium chloride and 24 mg of benzoic acid in 1.8 mL of N,N-dimethylformamide, heat at 80°C for 1 h, and cool to room temperature; liquid B: 36 mg of 1,4-dibromo -2,3,5,6-Tetracarboxyphenyl-substituted benzene was dissolved in 1.8mL N,N-dimethylformamide; the prepared solution A, B and 288mg benzoic acid were mixed uniformly, heated at 100°C for 2- 72h to obtain white powdery NU-906 granules, ready for use;

(2) after the surface of the self-made silica carrier is smoothed with sandpaper, 50nm silica particles are coated and calcined at 550° C. for 5h to obtain a silica carrier with a smooth surface;

(3) Disperse 10 mg of NU-906 seed crystals in 2.6 mL of N,N-dimethylformamide so that the single sheet loading is 20 mg/cm ² , and assemble on the modified silica carrier by wet coating Form a dense layer of NU-906, ready for use;

(4) The pre-coated NU-906 carrier is placed in a PTFE liner with a stent, and the synthesis time, synthesis temperature and amount of formic acid are controlled, and the formic acid vapor assists the NU-906 particles to generate dense MOF film, after the reaction is completed, the obtained MOF film is soaked in acetone and stored for later use;

(5) Using the self-assembled device to evaluate the permeability of the MOF film, and to evaluate the long-term stability of the film;

(6) the preparation method of the MOF film is in-situ phase inversion;

(7) the synthesis temperature of described MOF film is 25-150 ^℃ ;

(8) the synthesis time of the MOF film is 2-48h;

(9) the amount of formic acid in the MOF membrane is 0.08-2000 μL/mg NU-906;

(10) The penetration evaluation system is 20wt%-95wt% ethanol/water, operating temperature is 20-120 ^°C ; 20wt%-95wt% butanol/water, operating temperature is 20-120 ^°C .

(10) When the amount of formic acid was 2 μL/mg NU-906, the separation factor for 90wt% ethanol/water was 437 and the flux was 3.1 kg/(m ² ·h) for the MOF membrane prepared after 100 °C reaction for 24 h; The 90 wt% butanol/water separation factor was 4250 and the flux was 2.1 kg/(m ² ·h).

(11) When the amount of formic acid was 2 μL/mg NU-906, the thickness of the MOF film prepared after reaction at 100 °C for 24 h was 130 nm, the film roughness was 6.7 nm, and the water contact angle was 57°.

Embodiment 3:

(1) Liquid A: dissolve 58.5 mg of zirconium chloride and 24 mg of benzoic acid in 1.8 mL of N,N-dimethylformamide, heat at 80°C for 1 h, and cool to room temperature; liquid B: 36 mg of 1,4-dibromo -2,3,5,6-Tetracarboxyphenyl-substituted benzene was dissolved in 1.8mL N,N-dimethylformamide; the prepared solution A, B and 288mg benzoic acid were mixed uniformly, heated at 100°C for 2- 72h to obtain white powdery NU-906 granules, ready for use;

(2) after the surface of the self-made silica carrier is smoothed with sandpaper, 50nm silica particles are coated and calcined at 550° C. for 5h to obtain a silica carrier with a smooth surface;

(3) Disperse 40 mg of NU-906 seed crystals in 2.6 mL of N,N-dimethylformamide so that the single sheet loading is 80 mg/cm ² , and assemble on the modified silica carrier by wet coating Form a dense layer of NU-906, ready for use;

(4) The pre-coated NU-906 carrier is placed in a PTFE liner with a stent, and the synthesis time, synthesis temperature and amount of formic acid are controlled, and the formic acid vapor assists the NU-906 particles to generate dense MOF film, after the reaction is completed, the obtained MOF film is soaked in acetone and stored for later use;

(5) Using the self-assembled device to evaluate the permeability of the MOF film, and to evaluate the long-term stability of the film;

(6) the preparation method of the MOF film is in-situ phase inversion;

(7) the synthesis temperature of described MOF film is 25-150 ^℃ ;

(8) the synthesis time of the MOF film is 2-48h;

(9) the amount of formic acid in the MOF membrane is 0.08-2000 μL/mg NU-906;

(10) The penetration evaluation system is 20wt%-95wt% ethanol/water, operating temperature is 20-120 ^°C ; 20wt%-95wt% butanol/water, operating temperature is 20-120 ^°C .

(11) When the amount of formic acid was 2 μL/mg NU-906, the separation factor for 90wt% ethanol/water was 473 and the flux was 2.8 kg/(m ² ·h) for the MOF membrane prepared after 100 °C reaction for 24 h; The 90 wt% butanol/water separation factor was 4532 and the flux was 2.2 kg/(m ² ·h).

(12) When the amount of formic acid was 2 μL/mg NU-906, the thickness of the MOF film prepared after 100 °C reaction for 24 h was 140 nm, the film roughness was 4.5 nm, and the water contact angle was 45°.

Embodiment 4:

(1) Liquid A: dissolve 58.5 mg of zirconium chloride and 24 mg of benzoic acid in 1.8 mL of N,N-dimethylformamide, heat at 80°C for 1 h, and cool to room temperature; liquid B: 36 mg of 1,4-dibromo -2,3,5,6-Tetracarboxyphenyl-substituted benzene was dissolved in 1.8mL N,N-dimethylformamide; the prepared solution A, B and 288mg benzoic acid were mixed uniformly, heated at 100°C for 2- 72h to obtain white powdery NU-906 granules, ready for use;

(2) after the surface of the self-made silica carrier is smoothed with sandpaper, 50nm silica particles are coated and calcined at 550° C. for 5h to obtain a silica carrier with a smooth surface;

(3) Disperse 90 mg of NU-906 seed crystals in 2.6 mL of N,N-dimethylformamide so that the single sheet loading is 180 mg/cm ² , and assemble on the modified silica carrier by wet coating Form a dense layer of NU-906, ready for use;

(4) The pre-coated NU-906 carrier is placed in a PTFE liner with a stent, and the synthesis time, synthesis temperature and amount of formic acid are controlled, and the formic acid vapor assists the NU-906 particles to generate dense MOF film, after the reaction is completed, the obtained MOF film is soaked in acetone and stored for later use;

(5) Using the self-assembled device to evaluate the permeability of the MOF film, and to evaluate the long-term stability of the film;

(6) the preparation method of the MOF film is in-situ phase inversion;

(7) the synthesis temperature of described MOF film is 25-150 ^℃ ;

(8) the synthesis time of the MOF film is 2-48h;

(9) the amount of formic acid in the MOF membrane is 0.08-2000 μL/mg NU-906;

(10) The penetration evaluation system is 20wt%-95wt% ethanol/water, operating temperature is 20-120 ^°C ; 20wt%-95wt% butanol/water, operating temperature is 20-120 ^°C .

(11) When the amount of formic acid was 2 μL/mg NU-906, the separation factor for 90wt% ethanol/water was 455 and the flux was 3.3 kg/(m ² ·h) for the MOF membrane prepared after reaction at 100 °C for 24 h; The 90 wt% butanol/water separation factor was 4672 and the flux was 2.5 kg/(m ² ·h).

(12) When the amount of formic acid was 2 μL/mg NU-906, the thickness of the MOF film prepared after 100 °C reaction for 24 h was 150 nm, the film roughness was 3.9 nm, and the water contact angle was 34°.

Embodiment 5:

(1) Liquid A: dissolve 58.5 mg of zirconium chloride and 24 mg of benzoic acid in 1.8 mL of N,N-dimethylformamide, heat at 80°C for 1 h, and cool to room temperature; liquid B: 36 mg of 1,4-dibromo -2,3,5,6-Tetracarboxyphenyl-substituted benzene was dissolved in 1.8mL N,N-dimethylformamide; the prepared solution A, B and 288mg benzoic acid were mixed uniformly, heated at 100°C for 2- 72h to obtain white powdery NU-906 granules, ready for use;

(2) after the surface of the self-made silica carrier is smoothed with sandpaper, 50nm silica particles are coated and calcined at 550° C. for 5h to obtain a silica carrier with a smooth surface;

(3) Disperse 125 mg of NU-906 seed crystals in 2.6 mL of N,N-dimethylformamide so that the single-chip loading is 250 mg/cm ² , and assemble on the modified silica carrier by wet coating Formed dense NU-906, ready for use;

(4) The pre-coated NU-906 carrier is placed in a PTFE liner with a stent, and the synthesis time, synthesis temperature and amount of formic acid are controlled, and the formic acid vapor assists the NU-906 particles to generate dense MOF film, after the reaction is completed, the obtained MOF film is soaked in acetone and stored for later use;

(5) Using the self-assembled device to evaluate the permeability of the MOF film, and to evaluate the long-term stability of the film;

(6) the preparation method of the MOF film is in-situ phase inversion;

(7) the synthesis temperature of described MOF film is 25-150 ^℃ ;

(8) the synthesis time of the MOF film is 2-48h;

(9) the amount of formic acid in the MOF membrane is 0.08-2000 μL/mg NU-906;

(10) The penetration evaluation system is 20wt%-95wt% ethanol/water, operating temperature is 20-120 ^°C ; 20wt%-95wt% butanol/water, operating temperature is 20-120 ^°C .

(11) When the amount of formic acid was 2 μL/mg NU-906, the MOF membrane prepared after 100 ℃ of reaction for 24 h had a separation factor of 600 for 90 wt% ethanol/water and a flux of 3.5 kg/(m ² ·h); The 90 wt% butanol/water separation factor was 8000 and the flux was 2.5 kg/(m ² ·h).

(12) When the amount of formic acid was 2 μL/mg NU-906, the thickness of the MOF film prepared after 100 °C reaction for 24 h was 110 nm, the film roughness was 1.6 nm, and the water contact angle was 15°.

Embodiment 6:

(1) Liquid A: dissolve 58.5 mg of zirconium chloride and 24 mg of benzoic acid in 1.8 mL of N,N-dimethylformamide, heat at 80°C for 1 h, and cool to room temperature; liquid B: 36 mg of 1,4-dibromo -2,3,5,6-Tetracarboxyphenyl-substituted benzene was dissolved in 1.8mL N,N-dimethylformamide; the prepared solution A, B and 288mg benzoic acid were mixed uniformly, heated at 100°C for 2- 72h to obtain white powdery NU-906 granules, ready for use;

(2) after the surface of the self-made silica carrier is smoothed with sandpaper, 50nm silica particles are coated and calcined at 550° C. for 5h to obtain a silica carrier with a smooth surface;

(3) Disperse 188 mg of NU-906 seed crystals in 2.6 mL of N,N-dimethylformamide so that the single sheet loading is 376 mg/cm ² , and assemble on the modified silica carrier by wet coating Form a dense layer of NU-906, ready for use;

(4) The pre-coated NU-906 carrier is placed in a PTFE liner with a stent, and the synthesis time, synthesis temperature and amount of formic acid are controlled, and the formic acid vapor assists the NU-906 particles to generate dense MOF film, after the reaction is completed, the obtained MOF film is soaked in acetone and stored for later use;

(5) Using the self-assembled device to evaluate the permeability of the MOF film, and to evaluate the long-term stability of the film;

(6) the preparation method of the MOF film is in-situ phase inversion;

(7) the synthesis temperature of described MOF film is 25-150 ^℃ ;

(8) the synthesis time of the MOF film is 2-48h;

(9) the amount of formic acid in the MOF membrane is 0.08-2000 μL/mg NU-906;

(10) The penetration evaluation system is 20wt%-95wt% ethanol/water, operating temperature is 20-120 ^°C ; 20wt%-95wt% butanol/water, operating temperature is 20-120 ^°C .

(11) When the amount of formic acid was 2 μL/mg NU-906, the MOF membrane prepared after 100 °C reaction for 24 h had a separation factor of 564 for 90 wt% ethanol/water and a flux of 3.8 kg/(m ² ·h); The 90 wt% butanol/water separation factor was 6030 and the flux was 2.9 kg/(m ² ·h).

(12) When the amount of formic acid was 2 μL/mg NU-906, the thickness of the MOF film prepared after 100 °C reaction for 24 h was 160 nm, the film roughness was 2.3 nm, and the water contact angle was 23°.

Embodiment 7:

(1) Liquid A: dissolve 58.5 mg of zirconium chloride and 24 mg of benzoic acid in 1.8 mL of N,N-dimethylformamide, heat at 80°C for 1 h, and cool to room temperature; liquid B: 36 mg of 1,4-dibromo -2,3,5,6-Tetracarboxyphenyl-substituted benzene was dissolved in 1.8mL N,N-dimethylformamide; the prepared solution A, B and 288mg benzoic acid were mixed uniformly, heated at 100°C for 2- 72h to obtain white powdery NU-906 granules, ready for use;

(2) after the surface of the self-made silica carrier is smoothed with sandpaper, 50nm silica particles are coated and calcined at 550° C. for 5h to obtain a silica carrier with a smooth surface;

(3) Disperse 250 mg of NU-906 seed crystals in 2.6 mL of N,N-dimethylformamide so that the single-chip loading is 500 mg/cm ² , and assemble on the modified silica carrier by wet coating Form a dense layer of NU-906, ready for use;

(4) The pre-coated NU-906 carrier is placed in a PTFE liner with a stent, and the synthesis time, synthesis temperature and amount of formic acid are controlled, and the formic acid vapor assists the NU-906 particles to generate dense MOF film, after the reaction is completed, the obtained MOF film is soaked in acetone and stored for later use;

(5) Using the self-assembled device to evaluate the permeability of the MOF film, and to evaluate the long-term stability of the film;

(6) the preparation method of the MOF film is in-situ phase inversion;

(7) the synthesis temperature of described MOF film is 25-150 ^℃ ;

(8) the synthesis time of the MOF film is 2-48h;

(9) the amount of formic acid in the MOF membrane is 0.08-2000 μL/mg NU-906;

(10) The penetration evaluation system is 20wt%-95wt% ethanol/water, operating temperature is 20-120 ^°C ; 20wt%-95wt% butanol/water, operating temperature is 20-120 ^°C .

(11) When the amount of formic acid was 2 μL/mg NU-906, the separation factor for 90wt% ethanol/water was 597 for the MOF membrane prepared after reaction at 100 °C for 24 h, and the flux was 3.7 kg/(m ² ·h); The 90 wt% butanol/water separation factor was 7869 and the flux was 3.2 kg/(m ² ·h).

(12) When the amount of formic acid was 2 μL/mg NU-906, the thickness of the MOF film prepared after 100 °C reaction for 24 h was 170 nm, the film roughness was 2.1 nm, and the water contact angle was 25°.

The process conditions of embodiment 8 to 16, see Table 1 for details (other conditions are the same as implementation 1)

Table 1

In conclusion, as shown in Figures 1 to 5, in this study, MOF membranes prepared by in situ phase inversion method were prepared by in situ phase inversion after reaction at 100 °C for 24 h when the amount of formic acid was 2 μL/mg NU-906 and the seed loading was 250 mg/cm ² . The thickness was 110 nm, the film roughness was 1.6 nm, and the water contact angle was 15°. The MOF films prepared under different synthesis conditions are relatively dense and have a thickness of 100 nanometers. When the seed loading is 250 mg/cm ² , the film prepared by the in situ phase inversion method is the thinnest, so this study can be used for ultra The preparation of thin MOFs provides rich theoretical guidance. At the same time, in the separation process, the MOF films prepared under different conditions showed good separation effect, which laid a solid foundation for the industrial application of the membrane. The present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative and not restrictive. Those of ordinary skill in the art, under the inspiration of the present invention, do not depart from the spirit of the present invention. Under certain circumstances, more modifications can also be made, which all fall within the protection of the present invention.

Claims (6)

1. The method for preparing the MOF film by the in-situ phase inversion method is characterized by mainly comprising the following steps:

(1) preparing NU-906 particles;

(2) polishing the surface of a self-made silicon dioxide carrier by using sand paper, coating 50nm silicon dioxide particles, and calcining for 5 hours at 550 ℃ to obtain the silicon dioxide carrier with a smooth and flat surface;

(3) dispersing the prepared NU-906 seed crystals in a solvent, and assembling the seed crystals on a modified silicon dioxide carrier by a wet coating mode to form a compact NU-906 layer for later use;

(4) placing the carrier loaded with the NU-906 particles in a polytetrafluoroethylene liner with a support, adding formic acid, controlling time and temperature to enable the NU-906 particles to generate a compact MOF film through in-situ phase transformation, and soaking the obtained MOF film in acetone for storage after the reaction is finished;

(5) evaluating the permeability of the MOF film by using a self-assembled device, and evaluating the long-term stability of the film;

(6) the surface appearance and the thickness of the MOF film are represented by SEM, the XRD reflects the orientation of the MOF film, the surface roughness of the MOF film is observed by AFM, the water contact angle is tested to test the hydrophilicity of the MOF film at different time, and the structural characteristics and the separation performance of the oriented MOF film are further explained;

the load of the NU-906 in the step (3) is 5-500mg/cm²；

The reaction temperature of the MOF film in the step (4) is 25-150 ℃;

the reaction time of the MOF film in the step (4) is 2-48 h;

the amount of formic acid in the step (4) is 0.08-2000 mu L/mg NU-906.

2. The method according to claim 1, wherein the solvent of step (3) comprises N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, water, lower alkanols (C1-C6), acetonitrile, acetone or ethyl acetate.

3. The method of claim 1, wherein the step (4) MOF film is prepared by in-situ phase inversion.

4. The method according to claim 1, wherein the penetration evaluation systems of the step (5) are 20 wt% -95 wt% ethanol/water respectively, and the operating temperature is 20-120 ℃; 20 wt% -95 wt% butanol/water, and the operation temperature is 20-120 ℃.

5. The method according to claim 1, characterized in that step (1) is in particular:

solution A: dissolving 58.5mg of zirconium chloride and 24mg of benzoic acid in 1.8mL of N, N-dimethylformamide, heating at 80 ℃ for 1h, and cooling to room temperature; and B, liquid B: 36mg of 1, 4-dibromo-2, 3,5, 6-tetracarboxyphenyl substituted benzene was dissolved in 1.8mL of N, N-dimethylformamide; mixing the prepared solution A, solution B and 288mg benzoic acid, and heating at 100 deg.C for 2-72 hr to obtain white powdered NU-906 granule.

6. Use of MOF films prepared by in situ phase inversion prepared by the method of any of claims 1 to 5 for ethanol/water, butanol/water separations.

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