A molecular hybrid membrane for hydrogen purification, its preparation method, and its application.

Abstract

This invention proposes a molecular hybrid membrane for hydrogen purification, its preparation method, and its application. It is prepared using a zirconium oxide cluster and a benzimidazole-linked polymer. The zirconium oxide cluster exists as discrete nanoclusters in aqueous solution, achieving molecular-level hybridization with the benzimidazole-linked polymer. The molecular hybrid membrane contains benzimidazole and covalent and hydrogen bonds formed by the hybridization, as shown in the schematic structural formula below. An amino monomer and zirconium oxide cluster are dispersed in water as the aqueous phase, and an aldehyde monomer is dispersed in benzene as the organic phase. Then, a molecular hybrid membrane is prepared on the surface of a porous support through a simple interfacial polymerization process. At a temperature of 150℃ and a transmembrane pressure difference of 1 bar, the H2 permeation rate reaches 318 GPU, and the H2 / CO2 selectivity reaches 75.6. At a temperature of 300℃ and a transmembrane pressure difference of 1 bar, the H2 permeation rate is 1.48 × 10⁻⁶. 3 GPU, H2 / CO2 selectivity reaches 23.6.

Description

Technical Field

[0001] This invention belongs to the field of gas separation membrane preparation technology, and in particular relates to a zirconium-oxygen cluster hybridized benzimidazole-linked polymer molecular hybrid membrane and its interfacial polymerization preparation method; it proposes a molecular hybrid membrane for hydrogen purification, its preparation method and application; it is applicable to the separation of H2 and CO2 mixed gases generated by water-gas shift reaction in the process of hydrogen production from fossil fuels. Background Technology

[0002] Water-gas conversion (WGS) technology is widely used in the production of hydrogen from fossil fuels. It typically involves two stages: a high-temperature (HT WGS) step at 320-360°C and 10-60 bar, and a low-temperature (LT WGS) step at 190-250°C and 10-40 bar, producing a mixture of hydrogen (H2), carbon dioxide (CO2), etc., which is then separated to obtain H2. Therefore, efficient H2 / CO2 separation under high-temperature conditions is crucial. Membrane separation is a low-energy-consumption, short-cycle, and space-saving separation technology that can achieve highly efficient and energy-saving H2 separation.

[0003] Many types of membranes are used for H2 purification. Inorganic membranes, such as palladium membranes, exhibit high permeability and selectivity for H2, but their preparation is difficult and costly. Organic membranes, such as polyimide membranes, have good mechanical and processing properties, mature synthesis processes, and are widely used, but they suffer from a trade-off between permeability and selectivity and lack stability at high temperatures. Therefore, developing membrane materials with high H2 permeability, selectivity, and temperature and pressure resistance is crucial.

[0004] Organic-inorganic hybrid membranes combine the advantages of polymers and inorganic materials, significantly improving gas separation performance. The key lies in selecting suitable hybrid materials. Benzimidazole-linked polymers possess a cross-linked network structure; the tight polymer chain structure, hydrogen bonds between chains, and π-π stacking give them size sieving capabilities and excellent thermal and chemical stability. However, the high degree of chain stacking also results in a lower H2 permeation rate for benzimidazole-linked polymer membranes, limiting their application in hydrogen purification. Therefore, it is necessary to select suitable materials for hybridization to improve separation performance. Zirconium-oxygen clusters are highly stable and easily prepared metal-oxygen clusters. Zirconium metal forms discrete nanoclusters by oxygen atom linkages and covering ligands. The properties of the entire cluster can be controlled by regulating the functional groups and chemical properties of the ligands, making it a suitable hybrid material. Summary of the Invention

[0005] The purpose of this invention is to provide a molecular hybrid membrane for hydrogen purification and its preparation method. The polymer material used is a benzimidazole-linked polymer, formed by the condensation of an aryl o-diamine compound and an aldehyde. Many monomers are available for the synthesis of benzimidazole-linked polymers; different monomers can yield polymer materials with different molecular structures and chain segments. For better hydrogen purification, this invention selects 1,2,4,5-phenyltetramine tetrahydrochloride and trimesoaldehyde, which have relatively short branches and can form a highly cross-linked polymer network for molecular sieving. The inorganic material used is a zirconium oxide cluster containing amino groups and with a small diameter. Benzimazole-linked polymers are poorly soluble in most solvents, making direct membrane preparation difficult. Therefore, this invention uses interfacial polymerization to prepare the hybrid membrane, thereby achieving molecular-level hybridization and obtaining a gas separation membrane with good hydrogen selectivity and high permeation rate.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0007] A molecular hybrid membrane for hydrogen purification is prepared using a zirconium oxide cluster and a benzimidazole-linked polymer. The zirconium oxide cluster exists as discrete nanoclusters in aqueous solution and achieves molecular-level hybridization with the benzimidazole-linked polymer. The molecular hybrid membrane contains benzimidazole and covalent and hydrogen bonds formed by the hybridization. The schematic structural formula is as follows:

[0008]

[0009] The method for preparing the molecular hybrid membrane for hydrogen purification of the present invention includes the following steps:

[0010] 1): Prepare an aqueous solution containing zirconium chloride octahydrate, glycine, and hydrochloric acid as the reaction solution, and carry out the reaction; heat-treat the solution after the reaction, and then collect the zirconium-oxygen clusters;

[0011] 2): Prepare an aqueous solution containing zirconium oxide clusters and 1,2,4,5-phenyltetramine tetrahydrochloride as the aqueous phase; prepare a benzene solution of pyromellitic methyl ether as the organic phase;

[0012] 3): The porous support is immersed in an aqueous solution and vacuum-treated to fully load the amino monomer. After treatment, it is dried until there are no obvious droplets on the surface of the support.

[0013] 4): The porous support loaded with amino monomers in step 3) is immersed in an organic phase solution to carry out interfacial polymerization. After the reaction is complete, it is taken out and dried to form a molecular hybrid film on the surface of the inorganic support.

[0014] In the reaction solution of step 1), the concentration of zirconium oxychloride octahydrate in water is 3.1 wt%, the concentration of glycine in water is 2.9 wt%, and the concentration of hydrochloric acid in water is 1.8 wt%.

[0015] The reaction temperature in step 1) is room temperature, the reaction time is 720-1440 h, and the post-reaction heat treatment temperature is room temperature to 80°C, the heat treatment time is 48-120 h.

[0016] In the aqueous phase of step 2), the concentration of zirconium oxide clusters in water is 0.1–1.2 wt%, and the concentration of 1,2,4,5-phenyltetramine tetrahydrochloride in water is 1.0–2.0 wt%.

[0017] In step 2), the concentration of pyromellitic aldehyde in benzene is 0.1–1.0 wt%.

[0018] The porous support in step 3) is one of α-Al2O3, γ-Al2O3, and polyacrylonitrile; the pore size of the porous support is 1-20 nm.

[0019] The absolute pressure used for vacuum treatment in step 3) is 0.01 to 0.90 bar, and the treatment time is 10 to 30 minutes.

[0020] In step 4), the interfacial polymerization reaction time is 0.5 to 3 hours, the reaction temperature is 40°C, the drying temperature after the reaction is room temperature, and the drying time is 48 to 96 hours.

[0021] The molecular hybrid membrane for hydrogen purification of the present invention is applied to the separation of H2 / CO2 mixed gas generated by the water-gas shift reaction in the process of producing hydrogen from fossil fuels.

[0022] The specific explanation is as follows:

[0023] A molecular hybrid membrane for hydrogen purification is prepared by polymer hybridization of zirconium oxide clusters and benzimidazole. Zirconium oxide clusters are metal-oxygen clusters with abundant amino groups. They exist as discrete nanoclusters in aqueous solution and can achieve molecular-level hybridization with benzimidazole-linked polymers. The molecular hybrid membrane contains benzimidazole and the resulting covalent and hydrogen bonds, avoiding the formation of extremely dense polymer networks and increasing the selective permeation channels for hydrogen.

[0024]

[0025] The molecular hybrid membrane disclosed in this invention differs from traditional mixed matrix membranes in that its structure is innovative. Specifically, the mixed matrix membrane is prepared by adding porous nanoparticles as a dispersed phase to the continuous polymer phase, combining the advantages of both to a certain extent, thereby improving gas separation performance. Traditional mixed matrix membranes use dispersed phases such as metal-organic frameworks (MOFs) and zeolites (ZIFs), which often tend to generate non-selective defects at high loading levels, leading to a decrease in membrane separation performance. In contrast, the zirconium oxide clusters used in the molecular hybrid membrane of this invention are relatively small in size (less than 3 nm) and contain abundant amino groups, exhibiting good water solubility. They can be fully dispersed in the aqueous phase during the interfacial polymerization process to participate in the reaction. After chemical crosslinking, molecular-level hybridization is achieved, thereby avoiding defect formation and improving gas separation performance.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] First, amino monomers and zirconium oxide clusters were dispersed in water as the aqueous phase, and aldehyde monomers were dispersed in benzene as the organic phase. Then, a molecular hybrid membrane was prepared on the surface of a porous support through a simple interfacial polymerization process. Subsequently, the molecular hybrid membrane was tested under different temperature and pressure conditions using a mixture of hydrogen and carbon dioxide. At a temperature of 150℃ and a transmembrane pressure difference of 1 bar, the H2 permeation rate reached 318 GPU, and the H2 / CO2 selectivity reached 75.6. At a temperature of 300℃ and a transmembrane pressure difference of 1 bar, the H2 permeation rate was 1.48 × 10⁻⁶. 3 GPU, H2 / CO2 selectivity reaches 23.6.

[0028] The advantages of this invention are: the synthesis process of zirconium oxide clusters is simple, has a high success rate, and is easy to prepare on a large scale. Using interfacial polymerization to prepare the membrane easily yields a thin, defect-free separation layer, providing greater flexibility in adjusting the membrane structure and performance. Furthermore, the process is simple, the reaction rate is fast, and it is easy to scale up. The prepared molecular hybrid membrane has numerous selective hydrogen permeation channels. The zirconium oxide clusters within the membrane, through the reaction of their amino groups with aldehyde monomers, can fix the loose sites of the polymer chains, reducing the channels for carbon dioxide permeation. Simultaneously, they can disrupt the polymer packing, preventing the formation of an extremely dense polymer network, thereby increasing the selective hydrogen permeation channels. This results in a molecular hybrid membrane with high hydrogen permeation rate and high selectivity, enabling effective hydrogen purification under different temperature and pressure conditions. Attached Figure Description

[0029] Figure 1 This is a SEM image of the surface of the zirconium-oxygen cluster hybrid molecular hybrid film in Example 1 of the present invention.

[0030] Figure 2 This is a SEM image of the surface of the zirconium-oxygen cluster hybrid molecular hybrid film in Example 3 of the present invention.

[0031] Figure 3 This is a cross-sectional SEM image of the zirconium-oxygen cluster hybrid molecular hybrid film in Example 3 of the present invention.

[0032] Figure 4 The gas separation performance of molecular hybrid membranes with different zirconium-oxygen cluster contents was evaluated.

[0033] Figure 5 This describes the gas separation performance of the molecular hybrid membrane in Example 3 of the present invention at different temperatures.

[0034] Figure 6 This describes the gas separation performance of the molecular hybrid membrane in Example 3 of the present invention under different pressures.

[0035] Figure 7 This describes the gas separation performance of the molecular hybrid membrane in Example 9 of the present invention under different pressures. Detailed Implementation

[0036] The present invention will be further described below with reference to examples. Unless otherwise specified, all chemicals and reagents used in the examples are commercially available.

[0037] Gas membrane separation performance test method: The membrane is sealed in a membrane cell, a specific temperature and pressure are applied to the feed side, argon gas is used to purge the permeate side and the gas separation performance is analyzed by chromatography. The entire system includes gas pipeline, membrane cell, tubular furnace, pressure regulating valve and gas chromatograph. The test temperature is 150 to 300°C and the test pressure is 1 to 11 bar.

[0038] Formula for calculating gas membrane separation performance:

[0039] Gas permeation rate of component i (P) i Calculation formula:

[0040]

[0041] Where N i The permeation rate of component i (mol·s) -1 A is the effective membrane area (m²). 2 );Δp i Let be the partial pressure difference (Pa) across component i on both sides of the membrane. Using a GPU as P... i The unit is 1 GPU = 3.35 × 10⁻⁶. -10 mol·m -2 ·Pa -1 ·s -1 .

[0042] Gas separation factor (α) H2 / CO2 The formula for calculating ) is:

[0043]

[0044] Among them, y H2 (x H2 ) and y CO2 (x CO2 These are the mole fractions of H2 and CO2 in the permeation assay (raw material side), respectively.

[0045] Gas selectivity (S) H2 / CO2 ) Calculate using equation (3):

[0046]

[0047] Where P H2 and P CO2 The permeation rates are H2 and CO2, respectively. Since the gas on the permeation side is significantly diluted by the purge gas, the selectivity is approximately equal to the separation factor.

[0048] Example 1

[0049] 1) At room temperature, 2.42 g of zirconium oxychloride octahydrate and 2.25 g of glycine were ultrasonically dissolved in 72 g of deionized water. 1.44 g of hydrochloric acid was added to control the pH of the reaction solution, and the mixture was ultrasonically treated for 5 min to dissolve all reagents. The mixture was then allowed to react at room temperature for 720 h. The resulting mixture was dried at room temperature for 120 h, and white zirconium oxide cluster powder was collected at the bottom of the reaction flask.

[0050] 2) At room temperature, 0.15 g of 1,2,4,5-phenyltetramine tetrahydrochloride and 0.01 g of zirconium oxide clusters were dissolved in 9.84 g of deionized water and sonicated to ensure complete dissolution, thus obtaining an aqueous solution; 0.05 g of trimesaldehyde was dissolved in 9.95 g of benzene solution and sonicated to ensure complete dissolution, thus obtaining an organic solution.

[0051] 3) Immerse the γ-Al2O3 support in an aqueous solution and place it in a vacuum oven with an absolute pressure of 0.10 bar to fully load it with amino monomers. After 15 min of treatment, remove the support and dry it until the surface solution evaporates to the point where there are no excess droplets.

[0052] 4) The support loaded with amino monomers in step 3) is immersed in an organic phase solution, so that the amino monomers and aldehyde monomers undergo interfacial polymerization at the two-phase interface in the porous support, forming a brown film on the surface of the support. After reacting at 40°C for 2 hours, the support is removed and placed in a fume hood at room temperature for drying for 48 hours to obtain a molecular hybrid film with a zirconium oxide cluster loading of 6%.

[0053] SEM characterization of the prepared membrane surface revealed that a continuous, defect-free benzimidazole-linked polymer membrane was formed on the surface of the γ-Al₂O₃ support. Figure 1 As shown. The gas separation performance of the membrane was tested under the conditions of a transmembrane pressure difference of 1 bar and a temperature of 150°C. Figure 4 As shown, its H2 permeation rate is 145 GPU, its CO2 permeation rate is 4.53 GPU, and its H2 / CO2 selectivity is 32.1.

[0054] Example 2

[0055] 1) At room temperature, 2.42 g of zirconium oxychloride octahydrate and 2.25 g of glycine were ultrasonically dissolved in 72 g of deionized water. 1.44 g of hydrochloric acid was added to control the pH of the reaction solution, and the mixture was ultrasonically treated for 5 min to dissolve all reagents. The mixture was then allowed to react at room temperature for 720 h. The resulting mixture was dried at room temperature for 120 h, and white zirconium oxide cluster powder was collected at the bottom of the reaction flask.

[0056] 2) At room temperature, 0.15 g of 1,2,4,5-phenyltetramine tetrahydrochloride and 0.04 g of zirconium oxide clusters were dissolved in 9.75 g of deionized water and sonicated to ensure complete dissolution, thus obtaining an aqueous solution; 0.05 g of trimesaldehyde was dissolved in 9.95 g of benzene solution and sonicated to ensure complete dissolution, thus obtaining an organic solution.

[0057] 3) Immerse the γ-Al2O3 support in an aqueous solution and place it in a vacuum oven with an absolute pressure of 0.10 bar to fully load it with amino monomers. After 15 min of treatment, remove the support and dry it until the surface solution evaporates to the point where there are no excess droplets.

[0058] 4) The support loaded with amino monomers in step 3) is immersed in an organic phase solution, so that the amino monomers and aldehyde monomers undergo interfacial polymerization at the two-phase interface in the porous support, forming a brown film on the surface of the support. After reacting at 40°C for 2 hours, the support is removed and placed in a fume hood at room temperature for drying for 72 hours to obtain a molecular hybrid film with a zirconium oxide cluster loading of 21%.

[0059] The prepared membrane thickness was approximately 40–60 nm. The gas separation performance of the membrane was tested under conditions of a transmembrane pressure difference of 1 bar and a temperature of 150 °C. Figure 4 As shown, its H2 permeation rate is 169 GPU, its CO2 permeation rate is 4.03 GPU, and its H2 / CO2 selectivity is 41.9.

[0060] Example 3

[0061] 1) At room temperature, 2.42 g of zirconium oxychloride octahydrate and 2.25 g of glycine were ultrasonically dissolved in 72 g of deionized water. 1.44 g of hydrochloric acid was added to control the pH of the reaction solution, and the mixture was ultrasonically treated for 5 min to dissolve all reagents. The mixture was then allowed to react at room temperature for 1080 h. The resulting mixture was dried at 80 °C for 48 h, and white zirconium oxide cluster powder was collected at the bottom of the reaction flask.

[0062] 2) At room temperature, 0.15 g of 1,2,4,5-phenyltetramine tetrahydrochloride and 0.10 g of zirconium oxide clusters were dissolved in 9.75 g of deionized water and sonicated to ensure complete dissolution, thus obtaining an aqueous solution; 0.05 g of trimesaldehyde was dissolved in 9.95 g of benzene solution and sonicated to ensure complete dissolution, thus obtaining an organic solution.

[0063] 3) Immerse the γ-Al2O3 support in an aqueous solution and place it in a vacuum oven with an absolute pressure of 0.10 bar to fully load it with amino monomers. After 15 min of treatment, remove the support and dry it until the surface solution evaporates to the point where there are no excess droplets.

[0064] 4) The support loaded with amino monomers in step 3) is immersed in an organic phase solution, so that the amino monomers and aldehyde monomers undergo interfacial polymerization at the two-phase interface in the porous support, forming a brown film on the surface of the support. After reacting at 40°C for 2 hours, the support is removed and placed in a fume hood at room temperature for drying for 48 hours to obtain a molecular hybrid film with a zirconium oxide cluster loading of 40%.

[0065] SEM characterization of the prepared membrane surface revealed that a continuous, defect-free molecular hybrid membrane was formed on the surface of the γ-Al₂O₃ support, such as... Figure 2 As shown in the figure. SEM characterization of the prepared membrane cross-section reveals that the γ-Al₂O₃ support successfully immobilized the two-phase interface during interfacial polymerization, thus forming a uniformly thick membrane of approximately 50 nm. Figure 3 As shown, the gas separation performance of the membrane was tested under different temperatures and pressures. With increasing temperature, the H2 permeation rate of the molecular hybrid membrane increased, while the H2 / CO2 selectivity decreased, as shown... Figure 5 As shown. Under a transmembrane pressure difference of 1 bar, at a temperature of 150℃, the H2 permeation rate is 318 GPU, the CO2 permeation rate is 4.22 GPU, and the H2 / CO2 selectivity is 75.2; at a temperature of 200℃, the H2 permeation rate is 863 GPU, the CO2 permeation rate is 22.5 GPU, and the H2 / CO2 selectivity is 38.3; at a temperature of 250℃, the H2 permeation rate is 1.03 × 10⁻⁶. 3 The CO2 permeation rate was 42.0 GPU, and the H2 / CO2 selectivity was 24.6; at 300℃, the H2 permeation rate was 1.48 × 10⁻⁶. 3The pressure was 62.3 GHz, the CO2 permeation rate was 62.3 GHz, and the H2 / CO2 selectivity was 23.6 GHz. With increasing pressure, both the H2 permeation rate and H2 / CO2 selectivity of the molecular hybrid membrane decreased. Figure 6 As shown in the figure. Under the test temperature of 150℃, when the transmembrane pressure difference is 2.0 bar, the H2 permeation rate is 237 GPU, the CO2 permeation rate is 5.59 GPU, and the H2 / CO2 selectivity is 42.3; when the transmembrane pressure difference is 5.0 bar, the H2 permeation rate is 230 GPU, the CO2 permeation rate is 6.23 GPU, and the H2 / CO2 selectivity is 36.9; when the transmembrane pressure difference is 9.0 bar, the H2 permeation rate is 147 GPU, the CO2 permeation rate is 6.10 GPU, and the H2 / CO2 selectivity is 24.0; when the transmembrane pressure difference is 11.0 bar, the H2 permeation rate is 126 GPU, the CO2 permeation rate is 6.02 GPU, and the H2 / CO2 selectivity is 21.0.

[0066] Example 4

[0067] 1) At room temperature, 2.42 g of zirconium oxychloride octahydrate and 2.25 g of glycine were ultrasonically dissolved in 72 g of deionized water. 1.44 g of hydrochloric acid was added to control the pH of the reaction solution, and the mixture was ultrasonically treated for 5 min to dissolve all reagents. The mixture was then allowed to react at room temperature for 1080 h. The resulting mixture was dried at 80 °C for 48 h, and white zirconium oxide cluster powder was collected at the bottom of the reaction flask.

[0068] 2) At room temperature, 0.15 g of 1,2,4,5-phenyltetramine tetrahydrochloride and 0.10 g of zirconium oxide clusters were dissolved in 9.75 g of deionized water and sonicated to ensure complete dissolution, thus obtaining an aqueous solution; 0.05 g of trimesaldehyde was dissolved in 9.95 g of benzene solution and sonicated to ensure complete dissolution, thus obtaining an organic solution.

[0069] 3) Immerse the γ-Al2O3 support in an aqueous solution and place it in a vacuum oven with an absolute pressure of 0.10 bar to fully load it with amino monomers. After 15 min of treatment, remove the support and dry it until the surface solution evaporates to the point where there are no excess droplets.

[0070] 4) The support loaded with amino monomers in step 3) is immersed in an organic phase solution, so that the amino monomers and aldehyde monomers undergo interfacial polymerization at the two-phase interface in the porous support, forming a brown film on the surface of the support. After reacting at 40°C for 0.5 h, the support is removed and placed in a fume hood at room temperature for drying for 48 h to obtain a molecular hybrid film with a zirconium oxide cluster loading of 40%.

[0071] The gas separation performance of the membrane was tested at a temperature of 150℃. When the transmembrane pressure difference was 1 bar, the H2 permeation rate was 198 GPU, the CO2 permeation rate was 7.47 GPU, and the H2 / CO2 selectivity was 26.5. When the transmembrane pressure difference was 2 bar, the H2 permeation rate was 145 GPU, the CO2 permeation rate was 6.21 GPU, and the H2 / CO2 selectivity was 23.3.

[0072] Example 5

[0073] 1) At room temperature, 2.42 g of zirconium oxychloride octahydrate and 2.25 g of glycine were ultrasonically dissolved in 72 g of deionized water. 1.44 g of hydrochloric acid was added to control the pH of the reaction solution, and the mixture was ultrasonically treated for 5 min to dissolve all reagents. The mixture was then allowed to react at room temperature for 1080 h. The resulting mixture was dried at 80 °C for 48 h, and white zirconium oxide cluster powder was collected at the bottom of the reaction flask.

[0074] 2) At room temperature, 0.15 g of 1,2,4,5-phenyltetramine tetrahydrochloride and 0.10 g of zirconium oxide clusters were dissolved in 9.75 g of deionized water and sonicated to ensure complete dissolution, thus obtaining an aqueous solution; 0.05 g of trimesaldehyde was dissolved in 9.95 g of benzene solution and sonicated to ensure complete dissolution, thus obtaining an organic solution.

[0075] 3) Immerse the γ-Al2O3 support in an aqueous solution and place it in a vacuum oven with an absolute pressure of 0.10 bar to fully load it with amino monomers. After 15 min of treatment, remove the support and dry it until the surface solution evaporates to the point where there are no excess droplets.

[0076] 4) The support loaded with amino monomers in step 3) is immersed in an organic phase solution, so that the amino monomers and aldehyde monomers undergo interfacial polymerization at the two-phase interface in the porous support, forming a brown film on the surface of the support. After reacting at 40°C for 3.0 h, the support is removed and placed in a fume hood at room temperature for drying for 48 h to obtain a molecular hybrid film with a zirconium oxide cluster loading of 40%.

[0077] The gas separation performance of the membrane was tested at a temperature of 150℃. When the transmembrane pressure difference was 1 bar, the H2 permeation rate was 118 GPU, the CO2 permeation rate was 4.61 GPU, and the H2 / CO2 selectivity was 25.6. When the transmembrane pressure difference was 2 bar, the H2 permeation rate was 91.4 GPU, the CO2 permeation rate was 4.00 GPU, and the H2 / CO2 selectivity was 22.8.

[0078] Example 6

[0079] 1) At room temperature, 2.42 g of zirconium oxychloride octahydrate and 2.25 g of glycine were ultrasonically dissolved in 72 g of deionized water. 1.44 g of hydrochloric acid was added to control the pH of the reaction solution, and the mixture was ultrasonically treated for 5 min to dissolve all reagents. The mixture was then allowed to react at room temperature for 1080 h. The resulting mixture was dried at 80 °C for 48 h, and white zirconium oxide cluster powder was collected at the bottom of the reaction flask.

[0080] 2) At room temperature, 0.10 g of 1,2,4,5-phenyltetramine tetrahydrochloride and 0.10 g of zirconium oxide clusters were dissolved in 9.80 g of deionized water and sonicated to ensure complete dissolution, thus obtaining an aqueous solution; 0.01 g of trimesaldehyde was dissolved in 9.99 g of benzene solution and sonicated to ensure complete dissolution, thus obtaining an organic solution.

[0081] 3) Immerse the γ-Al2O3 support in an aqueous solution and place it in a vacuum oven with an absolute pressure of 0.10 bar to fully load it with amino monomers. After 20 minutes of treatment, remove the support and dry it until the surface solution evaporates to the point where there are no excess droplets.

[0082] 4) The support loaded with amino monomers in step 3) is immersed in an organic phase solution, so that the amino monomers and aldehyde monomers undergo interfacial polymerization at the two-phase interface in the porous support, forming a brown film on the surface of the support. After reacting at 40°C for 2.0 h, the support is removed and placed in a fume hood at room temperature for drying for 48 h to obtain a molecular hybrid film with a zirconium oxide cluster loading of 40%.

[0083] The gas separation performance of the membrane was tested at 150℃. When the transmembrane pressure difference was 1 bar, the H2 permeation rate was 124 GPU, the CO2 permeation rate was 16.7 GPU, and the H2 / CO2 selectivity was 7.41. When the transmembrane pressure difference was 2 bar, the H2 permeation rate was 105 GPU, the CO2 permeation rate was 14.9 GPU, and the H2 / CO2 selectivity was 7.04.

[0084] Example 7

[0085] 1) At room temperature, 2.42 g of zirconium oxychloride octahydrate and 2.25 g of glycine were ultrasonically dissolved in 72 g of deionized water. 1.44 g of hydrochloric acid was added to control the pH of the reaction solution, and the mixture was ultrasonically treated for 5 min to dissolve all reagents. The mixture was then allowed to react at room temperature for 1080 h. The resulting mixture was dried at 80 °C for 48 h, and white zirconium oxide cluster powder was collected at the bottom of the reaction flask.

[0086] 2) At room temperature, 0.20 g of 1,2,4,5-phenyltetramine tetrahydrochloride and 0.10 g of zirconium oxide clusters were dissolved in 9.70 g of deionized water and sonicated to ensure complete dissolution, thus obtaining an aqueous solution; 0.10 g of trimesin was dissolved in 9.90 g of benzene solution and sonicated to ensure complete dissolution, thus obtaining an organic solution.

[0087] 3) Immerse the γ-Al2O3 support in an aqueous solution and place it in a vacuum oven with an absolute pressure of 0.10 bar to fully load it with amino monomers. After 10 min of treatment, remove the support and dry it until the surface solution evaporates to the point where there are no excess droplets.

[0088] 4) The support loaded with amino monomers in step 3) is immersed in an organic phase solution, so that the amino monomers and aldehyde monomers undergo interfacial polymerization at the two-phase interface in the porous support, forming a brown film on the surface of the support. After reacting at 40°C for 2.0 h, the support is removed and placed in a fume hood at room temperature for drying for 72 h to obtain a molecular hybrid film with a zirconium oxide cluster loading of 40%.

[0089] The gas separation performance of the membrane was tested at a temperature of 150℃. When the transmembrane pressure difference was 1 bar, the H2 permeation rate was 106 GPU, the CO2 permeation rate was 2.96 GPU, and the H2 / CO2 selectivity was 35.6. When the transmembrane pressure difference was 2 bar, the H2 permeation rate was 89.9 GPU, the CO2 permeation rate was 3.01 GPU, and the H2 / CO2 selectivity was 29.9.

[0090] Example 8

[0091] 1) At room temperature, 2.42 g of zirconium oxychloride octahydrate and 2.25 g of glycine were ultrasonically dissolved in 72 g of deionized water. 1.44 g of hydrochloric acid was added to control the pH of the reaction solution, and the mixture was ultrasonically treated for 5 min to dissolve all reagents. The mixture was then allowed to react at room temperature for 1440 h. The resulting mixture was dried at 50 °C for 84 h, and white zirconium oxide cluster powder was collected at the bottom of the reaction flask.

[0092] 2) At room temperature, 0.15 g of 1,2,4,5-phenyltetramine tetrahydrochloride and 0.12 g of zirconium oxide clusters were dissolved in 9.75 g of deionized water and sonicated to ensure complete dissolution, thus obtaining an aqueous solution; 0.05 g of trimesin was dissolved in 9.95 g of benzene solution and sonicated to ensure complete dissolution, thus obtaining an organic solution.

[0093] 3) Immerse the γ-Al2O3 support in an aqueous solution and place it in a vacuum oven with an absolute pressure of 0.20 bar to fully load it with amino monomers. After 30 minutes of treatment, remove the support and dry it until the surface solution evaporates to the point where there are no excess droplets.

[0094] 4) The support loaded with amino monomers in step 3) is immersed in an organic phase solution, so that the amino monomers and aldehyde monomers undergo interfacial polymerization at the two-phase interface in the porous support, forming a brown film on the surface of the support. After reacting at 40°C for 2 hours, the support is removed and placed in a fume hood at room temperature for drying for 48 hours to obtain a molecular hybrid film with a zirconium oxide cluster loading of 44%.

[0095] The gas separation performance of the membrane was tested under the conditions of a transmembrane pressure difference of 1 bar and a temperature of 150°C. Figure 4 As shown, its H2 permeation rate is 124 GPU, its CO2 permeation rate is 2.57 GPU, and its H2 / CO2 selectivity is 55.9.

[0096] Example 9

[0097] 1) At room temperature, 2.42 g of zirconium oxychloride octahydrate and 2.25 g of glycine were ultrasonically dissolved in 72 g of deionized water. 1.44 g of hydrochloric acid was added to control the pH of the reaction solution, and the mixture was ultrasonically treated for 5 min to dissolve all reagents. The mixture was then allowed to react at room temperature for 1080 h. The resulting mixture was dried at 80 °C for 48 h, and white zirconium oxide cluster powder was collected at the bottom of the reaction flask.

[0098] 2) At room temperature, 0.15 g of 1,2,4,5-phenyltetramine tetrahydrochloride and 0.10 g of zirconium oxide clusters were dissolved in 9.75 g of deionized water and sonicated to ensure complete dissolution, thus obtaining an aqueous solution; 0.05 g of trimesaldehyde was dissolved in 9.95 g of benzene solution and sonicated to ensure complete dissolution, thus obtaining an organic solution.

[0099] 3) Immerse the polyacrylonitrile support in an aqueous solution and place it in a vacuum oven with an absolute pressure of 0.90 bar to fully load it with amino monomers. After 15 minutes of treatment, remove the support and dry it until the surface solution evaporates to the point where there are no excess droplets.

[0100] 4) The polyacrylonitrile support loaded with amino monomers in step 3) is immersed in an organic phase solution, so that the amino monomers and aldehyde monomers undergo interfacial polymerization at the two-phase interface in the porous support, forming a brown film on the support surface. After reacting at 40°C for 2 hours, the support is removed and placed in a fume hood at room temperature for drying for 96 hours to obtain a molecular hybrid film with a zirconium oxide cluster loading of 40%.

[0101] The gas separation performance of the molecular hybrid membrane prepared on the polyacrylonitrile support was tested under different temperatures and pressures, such as... Figure 7As shown, under the test temperature of 150℃, when the transmembrane pressure difference is 1.0 bar, the H2 permeation rate is 165 GPU, the CO2 permeation rate is 4.14 GPU, and the H2 / CO2 selectivity is 39.7; when the transmembrane pressure difference is 2.0 bar, the H2 permeation rate is 710 GPU, the CO2 permeation rate is 298 GPU, and the H2 / CO2 selectivity is 2.38.

[0102] The test results show that the molecular hybrid membrane described in the examples exhibits significantly higher H2 / CO2 selectivity than Knudsen diffusion, and higher H2 permeability. Therefore, the molecular hybrid membrane prepared using the method described in this invention possesses high H2 / CO2 selectivity. By selecting the zirconium oxide cluster loading and interfacial polymerization conditions, the molecular hybrid membrane can simultaneously possess a high H2 permeation rate. The interfacial polymerization preparation method is simple, has mild conditions, and is easily scaled up.

[0103] The technical solutions disclosed and proposed in this invention can be implemented by those skilled in the art by appropriately modifying the conditions and routes, etc. Although the methods and preparation techniques of this invention have been described through preferred embodiments, those skilled in the art can obviously modify or recombine the methods and technical routes described herein without departing from the content, spirit, and scope of this invention to achieve the final preparation technique. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the spirit, scope, and content of this invention.

Claims

1. A method for producing a molecular hybrid membrane for hydrogen purification, characterized by, The method comprises the following steps: 1) configuring an aqueous solution containing zirconium oxychloride octahydrate, glycine and hydrochloric acid as a reaction solution, and performing a reaction; and performing a heat treatment on the solution after the reaction, and then collecting zirconium oxygen clusters; 2) configuring an aqueous solution containing zirconium oxygen clusters and 1,2,4,5-benzene tetraamine tetrahydrochloride as an aqueous phase; and configuring a benzene solution of triformylphenyl as an organic phase; 3) immersing a porous carrier in the aqueous phase solution, and performing a vacuum treatment to sufficiently load the amino monomer, and then drying the porous carrier after the treatment to remove obvious liquid drops on the surface of the carrier; 4) immersing the porous carrier loaded with the amino monomer in the organic phase solution to perform an interfacial polymerization reaction, and then removing and drying the porous carrier after the reaction to form a molecular hybrid film on the surface of the inorganic carrier.

2. The method of claim 1 wherein, In the reaction solution of step 1), the concentration of zirconium oxychloride octahydrate in water is 3.1 wt%, the concentration of glycine in water is 2.9 wt%, and the concentration of hydrochloric acid in water is 1.8 wt%.

3. The method of claim 1 wherein, The reaction temperature of step 1) is room temperature, the reaction time is 720-1440 h, the heat treatment temperature after the reaction is room temperature-80 ℃, and the heat treatment time is 48-120 h.

4. The method of claim 1 wherein, In the aqueous phase of step 2), the concentration of zirconium oxygen clusters in water is 0.1-1.2 wt%, and the concentration of 1,2,4,5-benzene tetraamine tetrahydrochloride in water is 1.0-2.0 wt%.

5. The method of claim 1 wherein, In the organic phase of step 2), the concentration of triformylphenyl in benzene is 0.1-1.0 wt%.

6. The method of claim 1 wherein, The porous carrier of step 3) is one of α-Al2O3, γ-Al2O3 and polyacrylonitrile; and the pore size of the porous carrier is 1-20 nm.

7. The method of claim 1 wherein, The absolute pressure used in the vacuum treatment is 0.01-0.90 bar, and the treatment time is 10-30 min.

8. The method of claim 1 wherein, The interfacial polymerization reaction time in step 4) is 0.5-3 h, the reaction temperature is 40 ℃, the drying temperature after the reaction is room temperature, and the drying time is 48-96 h.

9. The molecular hybrid membrane for hydrogen purification produced by the method of claim 1, characterized by, The zirconium oxygen clusters and the benzimidazole connecting polymer are hybridized; the zirconium oxygen clusters exist in the form of discrete nanoclusters in an aqueous solution, and are hybridized with the benzimidazole connecting polymer at a molecular level, the molecular hybrid film contains benzimidazole and covalent bonds and hydrogen bonds formed by hybridization, and the schematic structural formula is as follows: 。 10. The molecular hybrid film for hydrogen purification according to claim 9 is applied to separation of H2 / CO2 mixed gas generated in a water vapor shift reaction in a fossil fuel hydrogen production process.

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