A polyamide-benzimidazole connected polymer film and its preparation method and application

Abstract

The present invention relates to a polyamide-benzimidazole-connected polymer membrane and a preparation method and application thereof; a support is immersed in an aqueous solution of 1,2,4,5-benzene tetraamine tetrahydrochloride, then taken out and allowed to stand until there are no obvious droplets on the surface of the support; then immersed in an organic solution of 1,3,5-benzenetricarboxylic acid chloride, a polymerization reaction occurs on the surface of the support to obtain a mesh polyamide membrane; the mesh polyamide membrane is placed in an oven, and a heating reaction is performed to obtain a polyamide-benzimidazole-connected polymer membrane. The prepared PA-BILP membrane is applied to the separation of H2 / CO2, H2 / N2, and H2 / CH4; at 150°C and 10bar, the H2 permeability is 58.7GPU, and the H2 / CO2 selectivity is 35.8. The method of the present invention is simple to operate and has a short preparation cycle; it has high gas permeability, high selectivity, good stability, and is easy to prepare on a large scale under high temperature and high pressure, meeting actual industrial conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer membrane preparation, and relates to a polyamide-benzimidazole linked polymer membrane (PA-BILP) and a preparation method and application thereof; the PA-BILP is suitable for the gas separation field of H2 / CO2, H2 / N2, H2 / CH4 mixed gases at different temperatures (25-300°C) and pressures (1-11 bar), and H2 purification and CO2 capture under high temperature and high pressure (temperature range: 150-300°C, pressure greater than 10 bar). Background Art

[0002] H2 is a clean, efficient, safe and sustainable secondary energy source. At present, more than 90% of H2 comes from fossil energy. Fossil fuels are first steam reformed or vaporized, and then undergo a water-gas shift reaction (temperature 150-300°C, pressure 7-10 bar) to produce H2, CO2 and other conversion gases. Therefore, the effective separation of H2 and CO2 under high temperature and high pressure is crucial to achieve H2 purification and CO2 capture. In industry, the main methods of H2 separation and CO2 capture are absorption, adsorption and low-temperature separation. Although these methods have been applied in practice to a certain extent, they belong to large-scale chemical equipment and are prone to environmental pollution. Gas membrane separation technology has the advantages of no phase change, no chemical reaction, low investment cost and operating energy consumption, small footprint and environmental pollution, and has been industrially applied in many fields.

[0003] The performance of the separation membrane mainly depends on the membrane material. The separation membranes used for H2 purification and CO2 capture mainly include inorganic membranes and organic membranes; inorganic membranes include metal membranes (palladium membranes and platinum membranes), silicon membranes, and zeolite membranes. Inorganic metal palladium membranes and platinum membranes have high selectivity for H2 and good thermal stability, but low H2 permeation rate, are sensitive to impurity gases (such as H2S, CO, etc.), have hydrogen embrittlement, and are costly. The silicon membrane has a simple preparation process, low production cost, and is easy to scale up production, but it is sensitive to water and water vapor. Porous membranes such as zeolite membranes have the advantages of high H2 permeation rate and high selectivity, but their production process is complex, the membrane is prone to defects, and it is difficult to prepare on a large scale. Organic membranes include polybenzimidazole (PBI) membranes, polyimide (PI) membranes, and covalent organic framework (COF) membranes, but there are currently no reports of actual industrial applications; compared with inorganic materials, organic membrane materials have low preparation costs, strong processability, and are easy to prepare on a large scale. The molecular dynamics diameters of H2 (0.29nm) and CO2 (0.33nm) differ by only 0.04nm. Currently, conventional organic polymer membranes reported in the literature cannot effectively separate the two. The polymer chains of polyimide (PI) membranes are not densely stacked, the screening effect is not obvious, and the selectivity is low. The covalent organic framework (COF) membrane has poor pressure resistance due to the weak interaction between COF chains and the weak bonding force with the support. The polymer chains of conventional linear polybenzimidazole (PBI) membranes are densely stacked, with low porosity and high rigidity, and low gas permeability, which does not meet application requirements. Traditional polyamide (PA) membranes are mainly used in water treatment and seawater desalination, and there are few reports on gas separation. Therefore, the development of H2 separation membranes with high permeability, high selectivity, and resistance to high temperature and high pressure is the key to achieving H2 purification and CO2 capture. Summary of the invention

[0004] The purpose of the present invention is to provide a polyamide-benzimidazole linked polymer (PA-BILP) membrane and a preparation method and application thereof for H2 purification and CO2 capture under high temperature and high pressure. A reticular polyamide (PA) membrane is prepared in situ by interfacial polymerization, and then the microstructure of the membrane is regulated by high-temperature reaction, so that part of the amide bonds are converted into benzimidazole bonds, and a small molecule selective gas permeation channel is constructed to achieve high gas permeability and high selectivity. Since the pyrolysis temperature of the benzimidazole linked reticular polymer (BILP) is as high as 600°C, and the polymer skeleton is highly rigid, the foundation is laid for the temperature and pressure resistance of the polyamide-benzimidazole linked polymer (PA-BILP) membrane. The PA-BILP membrane has good separation performance at different temperatures (25 to 300°C, especially high temperatures of 150 to 300°C) and pressures (1 to 11 bar), and large-scale preparation is achieved to meet the actual industrial conditions for H2 purification and CO2 capture. The reaction structure of the polyamide-benzimidazole linked polymer (PA-BILP) membrane is as follows:

[0005]

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a polyamide-benzimidazole linked polymer (PA-BILP) film, the process steps comprising:

[0008] 1) Soak the support in an aqueous solution of 1,2,4,5-benzenetetramine tetrahydrochloride at room temperature to fully immerse the solution into the support. Take it out after 10 to 60 minutes, blow air to remove excess liquid on the surface, and let it stand until there are no obvious droplets on the surface of the support.

[0009] 2): The support obtained in the first step is immersed in an organic solution of 1,3,5-benzenetricarboxylic acid chloride, and the 1,2,4,5-benzenetetramine tetrahydrochloride in the support reacts with 1,3,5-benzenetricarboxylic acid chloride on the surface of the support to obtain a mesh polyamide (PA) film, and the reaction time is 1 to 3600 seconds;

[0010] 3): Put the mesh polyamide (PA) film prepared in the second step into a preheated oven at 100-300° C., heat and react for 1-72 hours, then take it out and cool it naturally to room temperature; obtain a polyamide-benzimidazole linked polymer (PA-BILP) film.

[0011] In the step 1), the support body comprises one of an Al2O3 ceramic sheet, a ceramic tube, polysulfone, polyacrylonitrile, polyimide or a stainless steel support body.

[0012] The mass percentage concentration of 1,2,4,5-benzenetetraamine tetrahydrochloride in the aqueous solution of 1,2,4,5-benzenetetraamine tetrahydrochloride in step 1) is 0.01 to 20 wt %, preferably 0.15 to 1.5 wt %.

[0013] Furthermore, in the step 1), the support is immersed in the 1,2,4,5-benzenetetramine tetrahydrochloride aqueous solution and is preferably left to stand for 20 to 30 minutes.

[0014] The organic solvent in step 2) includes one of n-hexane, benzene or toluene.

[0015] In the step 2), the mass percentage concentration of 1,3,5-benzenetricarboxylic acid chloride in the organic solution containing 1,3,5-benzenetricarboxylic acid chloride is 0.01-1 wt %, preferably 0.1-0.5 wt %.

[0016] In the step 2), the reaction time of interfacial polymerization of 1,2,4,5-benzenetetraamine tetrahydrochloride and 1,3,5-benzenetricarboxylic acid chloride on the surface of the support is preferably 10 to 600 seconds, thereby obtaining a mesh polyamide (PA) membrane.

[0017] The heating reaction temperature in step 3) is preferably 150-200° C. and the heating reaction is carried out for 24 hours.

[0018] The polyamide-benzimidazole linked polymer (PA-BILP) membrane disclosed in the present invention is different from the traditional polyamide (PA) membrane and benzimidazole (PBI) membrane, and its structure is innovative. Specifically, the polyamide-benzimidazole linked polymer (PA-BILP) is a new porous organic polymer connected by amide bonds and benzimidazole bonds, and has a highly cross-linked network structure, such as Figure 1 The NMR spectrum shown confirms the presence of both amide bonds and benzimidazole bonds in the chemical structure of the separation membrane.

[0019] The present invention relates to a polyamide-benzimidazole linked (PA-BILP) polymer membrane for H2 purification and CO2 capture and a preparation method thereof; 1,2,4,5-benzenetetraamine tetrahydrochloride and 1,3,5-benzenetricarboxylic acid chloride are prepared into a membrane by interfacial polymerization, and then the microstructure of the membrane and the polymer chain stacking mode are regulated by high-temperature reaction, so as to effectively improve the tolerance (temperature resistance and pressure resistance) and separation performance (permeability and selectivity) of the polymer membrane. The prepared polyamide-benzimidazole linked polymer (PA-BILP) membrane allows the diffusion of molecules with small kinetic diameters and significantly hinders the migration of molecules with large kinetic diameters. The prepared PA-BILP membrane is applied to the separation of H2 / CO2, H2 / N2, and H2 / CH4; and is applied to H2 purification and CO2 capture under high temperature and high pressure environments, especially at high temperatures of 150 to 300° C. and pressures greater than 10 bar. At 150° C. and 10 bar, the H2 permeability is 58.7 GPU and the H2 / CO2 selectivity is 35.8. The method of the present invention is simple to operate and has a short preparation cycle. The disclosed interfacial polymerization method for preparing a polyamide-benzimidazole connected polymer membrane has high gas permeability, high selectivity, good stability, and is easy to prepare on a large scale under high temperature and high pressure, meets actual industrial conditions, reduces energy consumption, and can be used for H2 purification and CO2 capture.

[0020] The present invention has the following advantages:

[0021] First, the support is immersed in an aqueous solution of 1,2,4,5-benzenetetramine tetrahydrochloride and allowed to stand at room temperature to allow the aqueous solution to fully penetrate the support. Then, the support is immersed in an organic solution of 1,3,5-benzenetricarboxylic acid chloride. At room temperature, the two monomers undergo polymerization reaction on the surface of the support to obtain a porous polyamide (PA) membrane. The obtained porous polyamide (PA) membrane is then subjected to a thermal rearrangement reaction, such as Figure 1 As shown in the NMR spectrum, benzimidazole bonds are generated. The introduction of benzimidazole groups leads to changes in the microstructure of the membrane and the stacking mode of the polymer chains.

[0022] Interfacial polymerization is a method for preparing membrane materials at room temperature. It is simple and effective, has a fast reaction speed, and produces nanoscale polymer membranes with controllable thickness. The thermal rearrangement membrane treatment process regulates the microstructure of the polymer membrane and the stacking mode of the polymer chain, enhances the size screening effect, promotes the diffusion of molecules with small kinetic diameters (such as H2), and hinders the migration of molecules with large kinetic diameters (such as CO2, N2, CH4). The final polyamide-benzimidazole linked polymer (PA-BILP) membrane contains amide groups and benzimidazole groups, showing a cross-linked network structure and excellent stability. The polyamide-benzimidazole linked polymer (PA-BILP) membrane prepared by the method has high gas permeation rate, high selectivity, and good tolerance. At 150°C and 10bar, the H2 permeability is 58.7GPU, and the H2 / CO2 selectivity is 35.8, which can be used for the separation of H2 purification and CO2 capture under actual industrial conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the polyamide-benzimidazole linked polymer (PA-BILP) membrane in Example 5 of the present invention. 13 C NMR spectrum.

[0024] Figure 2 The gas separation performance of the polyamide-benzimidazole linked polymer (PA-BILP) membrane in Example 5 of the present invention at different test temperatures (25-300° C.) and constant pressure (1 bar).

[0025] Figure 3 The gas separation performance of the polyamide-benzimidazole linked polymer (PA-BILP) membrane in Example 5 of the present invention at a constant temperature (150° C.) and different test pressures (1 to 11 bar).

[0026] Figure 4 Cross-sectional SEM image of the polyamide-benzimidazole linked polymer (PA-BILP) film in Example 7 of the present invention. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present invention are described in detail below. Although the preferred embodiments of the present invention are described in detail below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments described herein.

[0028] Example 1

[0029] Step 1) Weigh 0.3g of 1,2,4,5-benzenetetramine tetrahydrochloride at room temperature and place it in a weighing bottle, add 19.7g of deionized water, and dissolve it completely by ultrasonication to obtain a 1.5wt% aqueous solution of 1,2,4,5-benzenetetramine tetrahydrochloride; fix the polyacrylonitrile support in the membrane assembly, and then slowly pour the prepared 1,2,4,5-benzenetetramine tetrahydrochloride aqueous solution into it to completely immerse the polyacrylonitrile support. After standing at room temperature for 10 minutes, pour off the excess aqueous solution and blow it with purge gas until there are no obvious droplets on the surface.

[0030] Step 2) Weigh 0.1g of 1,3,5-benzenetricarboxylic acid chloride into a 50ml weighing bottle, add 19.9g of n-hexane, and dissolve it completely by ultrasonication to obtain a 0.5wt% benzenetricarboxylic acid chloride benzene solution. Slowly pour the n-hexane solution into the membrane assembly in a fume hood, and the 1,3,5-benzenetricarboxylic acid chloride in the n-hexane solution reacts with the 1,2,4,5-benzenetetramine tetrahydrochloride on the surface of the polyacrylonitrile support for 1s. Let it stand in the fume hood until the solution on the membrane surface evaporates completely.

[0031] Step 3) The membrane prepared in step 2 is transferred to a preheated oven (100°C) for heating reaction for 24 hours, and then naturally cooled to room temperature and removed from the assembly. The membrane obtained at this time is a polyacrylonitrile-supported polyamide-benzimidazole linked polymer (PA-BILP) membrane.

[0032] The permeability and selectivity of the polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by polyacrylonitrile at 1 bar (the pressure in this patent indicates absolute pressure) and 150°C are as follows: H2 =1001GPU,P CO2 =65.1GPU,P H2 / P CO2 =15.4.

[0033] Example 2

[0034] Step 1) Weigh 0.01g of 1,2,4,5-benzenetetramine tetrahydrochloride at room temperature and place it in a weighing bottle, add 100g of deionized water, and dissolve it completely by ultrasonication to obtain a 0.01wt% aqueous solution of 1,2,4,5-benzenetetramine tetrahydrochloride; fix the polyacrylonitrile support in the membrane assembly, and then slowly pour the prepared 1,2,4,5-benzenetetramine tetrahydrochloride aqueous solution into it to completely immerse the polyacrylonitrile support. After standing at room temperature for 30 minutes, pour off the excess aqueous solution and blow it with purge gas until there are no obvious droplets on the surface.

[0035] Step 2) Weigh 0.1g of 1,3,5-benzenetricarboxylic acid chloride into a 50ml weighing bottle, add 9.9g of n-hexane, and dissolve it completely by ultrasonication to obtain a 0.5wt% n-hexane solution of 1,3,5-benzenetricarboxylic acid chloride. Slowly pour the n-hexane solution into the membrane assembly in a fume hood, and the 1,3,5-benzenetricarboxylic acid chloride in the n-hexane solution reacts with the 1,2,4,5-benzenetetramine tetrahydrochloride on the surface of the polyacrylonitrile support to polymerize. After reacting for 10s, let it stand in the fume hood until the solution on the membrane surface evaporates completely.

[0036] Step 3) The membrane prepared in step 2 is transferred to a preheated oven (150°C) for heating reaction for 24 hours, and then removed from the assembly after naturally cooling to room temperature. The membrane obtained at this time is a polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by a polyacrylonitrile.

[0037] The permeability and selectivity of the polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by polyacrylonitrile at 1 bar (the pressure in this patent indicates absolute pressure) and 150°C are as follows: H2 =1195GPU,P CO2 =65.3GPU,P H2 / P CO2 =18.3.

[0038] Example 3

[0039] Step 1) Weigh 0.3g of 1,2,4,5-benzenetetramine tetrahydrochloride at room temperature and place it in a weighing bottle, add 199.7g of deionized water, and dissolve it completely by ultrasonication to obtain a 0.15wt% aqueous solution of 1,2,4,5-benzenetetramine tetrahydrochloride; fix the polyacrylonitrile support in the membrane assembly, and then slowly pour the prepared 1,2,4,5-benzenetetramine tetrahydrochloride aqueous solution into it to completely immerse the polyacrylonitrile support. After standing at room temperature for 20 minutes, pour off the excess aqueous solution and blow it with purge gas until there are no obvious droplets on the surface.

[0040] Step 2) Weigh 0.1g of 1,3,5-benzenetricarboxylic acid chloride into a 50ml weighing bottle, add 9.9g of n-hexane, and dissolve it completely by ultrasonication to obtain a 1.0wt% n-hexane solution of 1,3,5-benzenetricarboxylic acid chloride. Slowly pour the n-hexane solution into the membrane assembly in a fume hood, and the 1,3,5-benzenetricarboxylic acid chloride in the n-hexane solution reacts with the 1,2,4,5-benzenetetramine tetrahydrochloride on the surface of the polyacrylonitrile support body to polymerize. After reacting for 60 minutes, leave it in a fume hood until the solution on the membrane surface evaporates completely.

[0041] Step 3) The membrane prepared in step 2 is transferred to a preheated oven (150°C) for heating reaction for 72 hours, and then removed from the assembly after naturally cooling to room temperature. The membrane obtained at this time is a polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by a polyacrylonitrile.

[0042] The permeability and selectivity of the polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by polyacrylonitrile at 1 bar (the pressure in this patent indicates absolute pressure) and 150°C are as follows: H2 =740GPU,P CO2 =17.6 GPU, P H2 / P CO2 =42.0.

[0043] Example 4

[0044] Step 1) Weigh 2g of 1,2,4,5-benzenetetramine tetrahydrochloride at room temperature and place it in a weighing bottle, add 8g of deionized water, and fully dissolve it by ultrasonication to obtain a 20wt% aqueous solution of 1,2,4,5-benzenetetramine tetrahydrochloride; place a γ-Al2O3 support in a weighing bottle, and slowly pour the prepared aqueous solution along the bottle wall to completely immerse the support. After standing at room temperature for 60 minutes, take out the γ-Al2O3 support, and evaporate the surface until there are no obvious droplets.

[0045] Step 2) Weigh 0.1g of 1,3,5-benzenetricarboxaldehyde and place it in a weighing bottle, add 9.9g of n-hexane, and completely dissolve it by ultrasound to obtain a 1wt% n-hexane solution of 1,3,5-benzenetricarboxylic acid chloride; place the γ-Al2O3 support soaked in the aqueous solution in a clean 30*Φ25cm weighing bottle, slowly pour the n-hexane solution into the weighing bottle in a fume hood to immerse the support, and the 1,3,5-benzenetricarboxylic acid chloride in the n-hexane solution reacts with the 1,2,4,5-benzenetetramine tetrahydrochloride in the support to undergo a polymerization reaction. After reacting for 3600s, the support is taken out of the solution and placed in a fume hood until the solution on the membrane surface is completely evaporated.

[0046] Step 3) The membrane prepared in step 2 is transferred to a preheated oven (200°C) for heating reaction for 1 hour, and then naturally cooled to room temperature and removed from the assembly. The membrane obtained at this time is a polyamide-benzimidazole linked polymer (PA-BILP) membrane on a γ-Al2O3 support.

[0047] The permeability and selectivity of the polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by γ-Al2O3 at 1 bar (the pressure in this patent indicates absolute pressure) and 150°C are as follows: H2 =36.0GPU,P CO2 =0.566 GPU, PH2 / P CO2 =63.6.

[0048] Example 5

[0049] Step 1) Weigh 0.3g of 1,2,4,5-benzenetetramine tetrahydrochloride at room temperature and place it in a weighing bottle, add 19.7g of deionized water, and dissolve it completely by ultrasonication to obtain a 1.5wt% aqueous solution of 1,2,4,5-benzenetetramine tetrahydrochloride; place a γ-Al2O3 support in a weighing bottle, and slowly pour the prepared aqueous solution along the bottle wall to completely immerse the support. After standing at room temperature for 20 minutes, take out the γ-Al2O3 support, absorb the bottom droplets with absorbent paper, and evaporate the surface until there are no obvious droplets.

[0050] Step 2) Weigh 0.1g of 1,3,5-benzenetricarboxylic acid chloride into a 50ml weighing bottle, add 19.9g of n-hexane, and dissolve it completely by ultrasonication to obtain a 0.5wt% n-hexane solution of 1,3,5-benzenetricarboxylic acid chloride. Place the γ-Al2O3 support soaked in the aqueous solution into a clean 30*Φ25cm weighing bottle, slowly pour the n-hexane solution into the weighing bottle in a fume hood to immerse the support, and the 1,3,5-benzenetricarboxylic acid chloride in the n-hexane solution reacts with the 1,2,4,5-benzenetetramine tetrahydrochloride in the support to undergo polymerization. After reacting for 600s, take the support out of the solution and wait for the solution on the membrane surface to evaporate completely in a fume hood.

[0051] Step 3) The membrane prepared in step 2 is transferred to a preheated oven (150°C) for heating reaction for 24 hours, and then cooled naturally to room temperature. The membrane obtained at this time is a polyamide-benzimidazole linked polymer (PA-BILP) membrane on a γ-Al2O3 support.

[0052] The permeability of H2 / CO2 mixed gas on the polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by γ-Al2O3 was tested at 1 bar and different temperatures (25-300°C). The gas separation performance diagram is shown in the figure below. Figure 2 The results show that the membrane has good gas separation performance and is resistant to high temperatures. The H2 / CO2 mixed gas permeability of the polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by γ-Al2O3 was tested at 150°C and different pressures (1 to 11 bar). The gas separation performance diagram is shown in the figure below. Figure 3 As shown, it indicates that the membrane has good gas separation performance and is resistant to high pressure.

[0053] Example 6

[0054] Step 1) Weigh 0.3g of 1,2,4,5-benzenetetramine tetrahydrochloride at room temperature and place it in a weighing bottle, add 19.7g of deionized water, and dissolve it completely by ultrasonication to obtain a 1.5wt% aqueous solution of 1,2,4,5-benzenetetramine tetrahydrochloride; place a γ-Al2O3 support in a weighing bottle, slowly pour the prepared aqueous solution along the bottle wall, and completely immerse the support. After standing at room temperature for 30 minutes, take out the γ-Al2O3 support, absorb the bottom droplets with absorbent paper, and evaporate the surface until there are no obvious droplets.

[0055] Step 2) Weigh 0.1g of 1,3,5-benzenetricarboxylic acid chloride into a 50ml weighing bottle, add 19.9g of n-hexane, and dissolve it completely by ultrasonication to obtain a 0.5wt% n-hexane solution of 1,3,5-benzenetricarboxylic acid chloride. Place the γ-Al2O3 support soaked in the aqueous solution into a clean 30*Φ25cm weighing bottle, slowly pour the n-hexane solution into the weighing bottle in a fume hood to immerse the support, and the 1,3,5-benzenetricarboxylic acid chloride in the n-hexane solution reacts with the 1,2,4,5-benzenetetramine tetrahydrochloride in the support to undergo polymerization. After reacting for 600s, take the support out of the solution and wait for the solution on the membrane surface to evaporate completely in a fume hood.

[0056] Step 3) The membrane prepared in step 2 is transferred to a preheated oven (300°C) for heating reaction for 24 hours, and then removed from the assembly after naturally cooling to room temperature. The membrane obtained at this time is a polyamide-benzimidazole linked polymer (PA-BILP) membrane on a γ-Al2O3 support.

[0057] The permeation performance and selectivity of H2 / CO2 mixed gas on the polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by γ-Al2O3 at 1 bar and different temperatures (25-300℃) are as follows: at 25℃, P H2 =67.7 GPU, P CO2 =2.55 GPU, P H2 / P CO2 =26.6; at 150°C, P H2 =176 GPU, P CO2 =1.50GPU,P H2 / P CO2 =177; at 200°C, P H2 =407 GPU, P CO2 =8.97 GPU, P H2 / P CO2 =45.4; at 250°C, P H2 =503GPU,P CO2 =10.9 GPU, P H2 / P CO2 =46.1; at 300°C, PH2 =786GPU,P CO2 =30.6 GPU, P H2 / P CO2 =25.7.

[0058] Example 7

[0059] Step 1) Weigh 0.3g of 1,2,4,5-benzenetetramine tetrahydrochloride at room temperature and place it in a weighing bottle, add 19.7g of deionized water, and dissolve it completely by ultrasonication to obtain a 1.5wt% aqueous solution of 1,2,4,5-benzenetetramine tetrahydrochloride; place a γ-Al2O3 support in a weighing bottle, and slowly pour the prepared aqueous solution along the bottle wall to completely immerse the support. After standing at room temperature for 20 minutes, take out the γ-Al2O3 support, absorb the bottom droplets with absorbent paper, and evaporate the surface until there are no obvious droplets.

[0060] Step 2) Weigh 0.1g of 1,3,5-benzenetricarboxylic acid chloride into a 50ml weighing bottle, add 19.9g of n-hexane, and dissolve it completely by ultrasonication to obtain a 0.5wt% n-hexane solution of 1,3,5-benzenetricarboxylic acid chloride. Place the γ-Al2O3 support soaked in the aqueous solution into a clean 30*Φ25cm weighing bottle, slowly pour the n-hexane solution into the weighing bottle in a fume hood to immerse the support, and the 1,3,5-benzenetricarboxylic acid chloride in the n-hexane solution reacts with the 1,2,4,5-benzenetetramine tetrahydrochloride in the support to undergo polymerization. After reacting for 600s, take the support out of the solution and wait for the solution on the membrane surface to evaporate completely in a fume hood.

[0061] Step 3) The membrane prepared in step 2 is transferred to a preheated oven (200°C) for heating reaction for 24 hours, and then removed from the assembly after cooling naturally to room temperature. The membrane obtained at this time is a polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by a γ-Al2O3 substrate. The membrane photo and cross-sectional scanning electron microscopy are as follows: Figure 4 shown.

[0062] The permeability and selectivity of four pure gases H2, N2, CO2, and CH4 on the polyamide-benzimidazole linked polymer (PA-BILP) membrane supported by γ-Al2O3 at 1 bar and 150°C are as follows: H2 =157 GPU, P CO2 =1.30GPU,P N2 =1.12GPU,P CH4 =1.09GPU,P H2 / P CO2 =121,P H2 / P N2 =140, P H2 / P CH4=143.6.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the requirements of the present invention should be included in the protection scope of the present invention.

[0064] The present invention discloses and proposes a polyamide-benzimidazole connected polymer membrane and a preparation method and application thereof. Those skilled in the art can realize the above by referring to the contents of this article and appropriately changing the conditions and routes. Although the method and preparation technology of the present invention have been described through preferred embodiments, relevant technicians can obviously modify or re-combine the methods and technical routes described herein without departing from the content, spirit and scope of the present invention to realize the final preparation technology. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the spirit, scope and content of the present invention.

Claims

1. A method for preparing a polyamide-benzimidazole connected polymer film, characterized in that: The steps include: 1): Soak the support in an aqueous solution of 1,2,4,5-benzenetetramine tetrahydrochloride, allow the solution to fully soak into the support and let it stand for 10 to 60 minutes at room temperature before taking it out, purge excess liquid on the surface with air and let it stand until there are no droplets on the surface of the support; 2): The support obtained in the first step is immersed in an organic solution of 1,3,5-benzenetricarboxylic acid chloride, and the 1,2,4,5-benzenetetramine tetrahydrochloride in the support reacts with 1,3,5-benzenetricarboxylic acid chloride on the surface of the support to obtain a mesh polyamide membrane, and the reaction time is 1-3600 s; the organic solvent is one of n-hexane, benzene or toluene; 3): Place the mesh polyamide membrane prepared in the second step into a preheated 100~300 o C oven, and after heating reaction for 1 to 72 h, the mixture was taken out and naturally cooled to room temperature to obtain a polyamide-benzimidazole connected polymer membrane.

2. The method for preparing a polyamide-benzimidazole connected polymer film according to claim 1, characterized in that: In step 1), the support body comprises one of Al2O3 ceramic sheet, ceramic tube, polysulfone, polyacrylonitrile, polyimide or stainless steel support body.

3. The method for preparing a polyamide-benzimidazole connected polymer film as claimed in claim 1, characterized in that: The mass percentage concentration of 1,2,4,5-benzenetetraamine tetrahydrochloride in the aqueous solution of 1,2,4,5-benzenetetraamine tetrahydrochloride in step 1) is 0.01-20 wt%.

4. The method for preparing a polyamide-benzimidazole connected polymer film as claimed in claim 1, characterized in that: In step 1), the support is immersed in the 1,2,4,5-benzenetetramine tetrahydrochloride aqueous solution and then allowed to stand for 20 to 30 minutes.

5. The method for preparing a polyamide-benzimidazole connected polymer film as claimed in claim 1, characterized in that: Step 2) The mass percentage concentration of 1,3,5-benzenetricarboxylic acid chloride in the organic solution containing 1,3,5-benzenetricarboxylic acid chloride is 0.01-1 wt %.

6. The method for preparing a polyamide-benzimidazole connected polymer film as claimed in claim 1, characterized in that: Step 2) The mass percentage concentration of 1,3,5-benzenetricarboxylic acid chloride in the organic solution containing 1,3,5-benzenetricarboxylic acid chloride is 0.1-0.5 wt%.

7. The method for preparing a polyamide-benzimidazole connected polymer film as claimed in claim 1, characterized in that: The mass percentage concentration of 1,2,4,5-benzenetetraamine tetrahydrochloride in the aqueous solution of 1,2,4,5-benzenetetraamine tetrahydrochloride in step 1) is 0.15-1.5 wt %; the mass percentage concentration of 1,3,5-benzenetricarboxylic acid chloride in step 2) is 0.1-0.5 wt %.

8. The method for preparing a polyamide-benzimidazole connected polymer film as claimed in claim 1, characterized in that: In step 2), the reaction time of interfacial polymerization of 1,2,4,5-benzenetetraamine tetrahydrochloride and 1,3,5-benzenetricarboxylic acid chloride on the surface of the support is 10-600 s, thereby obtaining a mesh polyamide membrane.

9. The method for preparing a polyamide-benzimidazole connected polymer film as claimed in claim 1, characterized in that: Step 3) The heating reaction temperature is 150~200 o C and reaction time 24 h.

10. Use of the polyamide-benzimidazole connected polymer membrane prepared by the method of claim 1, characterized in that: Used for separation of H2 / CO2, H2 / N2, H2 / CH4.

11. Use of the polyamide-benzimidazole connected polymer membrane prepared by the method of claim 1, characterized in that: For H2 purification and CO2 capture.

Images