A composite membrane based on MOF modification, a preparation method and application in ecco2r system

Abstract

The application discloses a composite membrane based on MOF modification, a preparation method and application in an ECCO2R system, and belongs to the technical field of gas separation membranes. The composite membrane is prepared by immersing a PMP hollow fiber membrane used in the ECCO2R system in a Pebax casting solution doped with MOF porous nanomaterials to perform membrane coating, the MOF porous nanomaterials are amino-functionalized ZIF-8 nanoparticles, and the Pebax comprises polyamide-polyether blocks. The composite membrane exhibits excellent CO2 / O2 selectivity in the ECCO2R system, has excellent carbon dioxide removal performance, and has good blood compatibility and biocompatibility, and is favorable to improving the carbon dioxide precipitation capacity of the membrane lung on human blood.

Description

Technical Field

[0001] This invention relates to the field of gas-blood exchange membrane technology, specifically to a composite membrane based on MOF modification, its preparation method, and its application in the ECCO2R system. Background Technology

[0002] With the continuous advancement of medical technology, the demands for respiratory support technology are increasing. Extracorporeal life support (ECLS) is a life support technology that uses mechanical devices to provide cardiopulmonary support (partial or complete) for several days to several months in cases of severe cardiopulmonary failure, and is an effective way to reduce the mortality rate of patients with respiratory failure. Extracorporeal membrane oxygenation (ECMO) is a part of ECLS. Over the past few decades, ECMO technology has made significant progress and effectively supported the respiratory function of some critically ill patients. However, the high operating cost, complexity of ECMO operation, and the risk of complications such as massive bleeding and blood trauma to patients limit its clinical application. To compensate for the shortcomings of ECMO in practical applications, extracorporeal carbon dioxide removal technology (ECCO2R) has emerged. Unlike ECMO, ECCO2R uses lower blood flow, smaller circuits, membranes, and cannulas, and is designed to remove carbon dioxide through extracorporeal circulation to help manage acute respiratory failure. Currently, ECCO2R is mainly used for severe exacerbations of chronic obstructive pulmonary disease (COPD) (aiming to reduce intubation rates and duration of mechanical ventilation) and moderate ARDS (to reduce ventilatory load to allow for "superprotective" ventilation settings).

[0003] ECCO2R works on the principle of an innovative extension of membrane oxygenation technology, reducing the concentration of carbon dioxide in the blood to maintain the blood's acid-base balance. During normal respiration, the lungs inhale oxygen into the blood and expel carbon dioxide. However, when patients suffer from severe respiratory failure or lung disease, lung function is impaired, and carbon dioxide cannot be effectively expelled. In this case, ECCO2R can serve as an auxiliary means of respiration, helping to expel accumulated carbon dioxide from the body. The ECCO2R system forms a circulation with venous blood, introducing blood into the extracorporeal circulation system. Outside the body, a series of specially designed exhaust membranes remove carbon dioxide from the blood. The carbon dioxide-free blood is then returned to the body, completing one cycle. Therefore, one of the main functions of ECCO2R is to help reduce the concentration of carbon dioxide in the patient's blood, reducing the burden on breathing.

[0004] The key factor affecting the effectiveness of ECCO2R is the performance of the gas exchange membrane. Poly(4-methyl-1-pentene) (PMP), a thermoplastic polyolefin, is used in ECCO2R systems due to its good mechanical stability, thermal stability, permeability, and resistance to plasma leakage. However, because membrane lungs (MLs) have low permeability to carbon dioxide and PMPs have low CO2 / O2 selectivity, the rate at which carbon dioxide concentration in the blood decreases is slow. This prolongs the equipment's lifespan and increases the risk of complications such as hemolysis and thrombosis. Under normal physiological lung ventilation, highly permeable ultrathin natural alveoli have a CO2 / O2 permeability selectivity of approximately 20:1, which facilitates optimal gas exchange efficiency and blood gas distribution. Therefore, to improve the effectiveness of ECCO2R, it is necessary to modify the PMP hollow fiber membrane to increase the CO2 mass transfer rate, requiring both high CO2 permeability and high CO2 / O2 selectivity.

[0005] Common membrane materials mainly include polymer membranes and inorganic membranes. However, existing polymer membrane materials are limited in terms of the trade-off (or "game") between permeability and selectivity, while inorganic membrane materials face challenges in large-scale production and cost control. Hybrid matrix membranes (or hybrid membranes, MMMs), also known as polymer-inorganic hybrid membranes, are composite membranes formed by the interaction between inorganic or inorganic-organic hybrid materials in the form of micron or nanoparticles (discrete or dispersed phase) and a polymer matrix (continuous phase). Compared with pure polymer membranes and inorganic membranes, MMMs overcome the trade-off between permeability and selectivity, and their preparation methods are simple, making them competitive membrane materials in the field of gas separation. They can combine the advantages of both polymer and inorganic membranes. Among them, molecular sieves, mesoporous silica particles, activated carbon, carbon nanotubes, and metal-organic frameworks (MOFs) have been widely used as fillers introduced into polymer matrices to prepare hybrid matrix membranes.

[0006] As suitable hybrid matrix membranes, it is necessary to maintain a balance between dispersed and continuous components. In this regard, MOFs have attracted particular attention due to the high compatibility between the organic portion of their framework and the polymer matrix. Chinese Patent CN115253725 B discloses a hybrid matrix membrane based on amino-modified MOF materials. The method involves dispersing the amino-modified MOF material in a membrane-forming solvent to prepare a solution, then adding a polymer matrix to the solution and stirring it uniformly at 20-60°C to prepare a casting solution. Finally, a hybrid matrix membrane is prepared using a solution casting method. When the resulting hybrid matrix membrane is used for CO2 separation, it provides more transport channels and affinity sites for CO2 transfer, exhibiting high CO2 permeability and CO2 / N2 selectivity.

[0007] In summary, incorporating porous nanofillers into a polymer matrix to construct biomimetic gas channels holds promise for addressing the low carbon dioxide permeability of membrane lungs. However, compared to pure parent polymer membrane materials or existing hybrid matrix membrane materials, few studies have reported that MOF-filled hybrid matrix membranes simultaneously exhibit high CO2 permeability and high CO2 / O2 selectivity. Furthermore, there have been no successful applications combining hybrid matrix membranes with PMP membranes. In other words, existing hybrid matrix membranes are still difficult to directly apply to ECCO2R systems for selective CO2 / O2 adsorption, and further research is needed on suitable membrane materials. Summary of the Invention

[0008] The purpose of this invention is to solve the problems existing in the prior art and provide a composite membrane based on MOF modification and its preparation method. By constructing a Pebax mixed matrix membrane doped with amino-functionalized ZIF-8 nanoparticles on the membrane of the ECCO2R system, the CO2 desorption performance, blood compatibility and biocompatibility of the original membrane are improved, which is beneficial to improving the membrane lung's ability to extract CO2 from human blood.

[0009] To achieve the above technical objectives, the present invention is implemented through the following technical solution: a method for preparing a composite membrane based on MOF modification, comprising the following preparation steps:

[0010] S1. Synthesize amino-functionalized ZIF-8 nanoparticles, denoted as ZIF-8-NH2;

[0011] S2. Preparation of Pebax casting solution: Mix Pebax, ethanol and pure water and heat in an oil bath;

[0012] S3. Preparation of modified solution: Disperse the ZIF-8-NH2 synthesized in step S1 in the casting solution prepared in step S2 by ultrasonic dispersion;

[0013] S4. Immerse the PMP hollow fiber membrane in the modified solution prepared in step S3, remove it and dry it to obtain the composite membrane, denoted as ZIF-8-NH2 / Pebax@PMP.

[0014] Further, in step S1, the steps for synthesizing ZIF-8-NH2 are as follows: soluble zinc salt, 2-methylimidazole, and 2-aminobenzimidazole are dissolved in an organic solvent, stirred to react, centrifuged, washed, and dried.

[0015] Further, in step S1, the organic solvent is methanol or ethanol, and the soluble zinc salt is zinc nitrate hexahydrate; the mass-to-volume ratio of the soluble zinc salt, 2-methylimidazole, 2-aminobenzimidazole to the organic solvent is 1.5 g:(1.5-6) ​​g:(0.3-1.2) g:100 mL; the centrifugation conditions are 10000 r / min for 10 min; the drying process is carried out at 60-80℃ for 24 h.

[0016] Furthermore, in step S2, the ratio of Pebax, ethanol, and pure water is (1-2) g:17 g:3 mL, and the heating conditions are: oil bath heating, 80-90℃, 4-6 h.

[0017] Furthermore, in step S3, the amount of ZIF-8-NH2 used is 0.1-0.5 g, and the mass ratio of ZIF-8-NH2 to Pebax in the casting solution is 1:(1-5).

[0018] Furthermore, in step S4, the PMP hollow fiber membrane is immersed in the modified solution for 10-50 seconds.

[0019] Preferably, the mass ratio of ZIF-8-NH2 to Pebax in the casting solution is 1:2.5, and the immersion time of the PMP hollow fiber membrane in the modified solution is 30 s.

[0020] The composite membrane structure was prepared using the above method by coating a membrane for the ECCO2R system with a Pebax mixed matrix membrane containing amino-functionalized ZIF-8 nanoparticles. The membrane for the ECCO2R system is a PMP hollow fiber membrane, and the Pebax includes a polyamide-polyether block. This composite membrane structure can be used for CO2 / O2 separation, improves CO2 / O2 selectivity, and enhances the blood compatibility and biocompatibility of the membrane for the ECCO2R system.

[0021] The beneficial effects of this invention are as follows:

[0022] 1. The composite membrane ZIF-8-NH2 / Pebax@PMP disclosed in this application is made by coating a Pebax mixed matrix membrane with modified MOF onto a PMP hollow fiber membrane used in the ECCO2R system. The Pebax includes polyamide-polyether blocks, and the modified MOF is amino-functionalized ZIF-8 nanoparticles. By limiting the doping ratio of modified MOF and the soaking time of the original membrane, the performance of the original membrane is improved, which significantly improves the CO2 / O2 selective adsorption of the membrane compared with the original PMP membrane.

[0023] 2. The hybrid matrix membrane disclosed in this application not only has high CO2 / O2 selectivity and excellent carbon dioxide removal performance, but also good biocompatibility and blood compatibility. These properties make it highly suitable for ECCO2R systems and help improve the membrane lung's ability to extract CO2 from human blood.

[0024] 3. In the preparation of the hybrid matrix membrane, this application uses Pebax as the polymer matrix, which is composed of rigid polyamide (PA) segments that provide mechanical strength and flexible polyether (PE) segments that provide gas transport. It has a strong selectivity for CO2 and can further improve the CO2 desorption capability of the PMP hollow fiber membrane.

[0025] 4. The composite membrane disclosed in this application has a simple and controllable preparation process, which provides a new idea for the preparation and application of porous material coatings and has broad application prospects. Attached Figure Description

[0026] Figure 1 The infrared spectra are those of the original PMP membrane and the modified membrane prepared in Example 4 (immersion time of 30 s);

[0027] Figure 2 These are electron microscope images of the original PMP membrane and the modified membrane prepared in Example 4 (immersion time of 30 s);

[0028] Figure 3 This is a graph showing the gas permeability data of the original PMP membrane and the modified ZIF-8-NH2 / Pebax@PMP composite membrane prepared in Example 1 at different immersion times;

[0029] Figure 4 This is a graph showing the gas permeability data of the original PMP membrane and the modified ZIF-8-NH2s / Pebax@PMP composite membrane prepared under different immersion times in Example 2.

[0030] Figure 5 This is a graph showing the gas permeability data of the original PMP membrane and the modified ZIF-8-NH2 / Pebax@PMP composite membrane prepared under different immersion times in Example 3;

[0031] Figure 6 This is a graph showing the gas permeability data of the original PMP membrane and the modified ZIF-8-NH2 / Pebax@PMP composite membrane prepared under different immersion times in Example 4;

[0032] Figure 7 This is a graph showing the gas permeability data of the original PMP membrane and the modified ZIF-8-NH2 / Pebax@PMP composite membrane prepared under different immersion times in Example 5;

[0033] Figure 8This is a graph showing the protein adsorption data of the original PMP membrane and the modified membrane prepared in Example 4 (immersion time of 30 s);

[0034] Figure 9 This is a graph showing the hemolysis rate data of the original PMP membrane and the modified membrane prepared in Example 4 (immersion time of 30 s);

[0035] Figure 10 This is a graph showing the coagulation time data of the original PMP membrane and the modified membrane prepared in Example 4 (immersion time of 30 s);

[0036] Figure 11 The platelet adhesion diagrams are of the original PMP membrane (left) and the modified membrane (right) prepared in Example 4 (immersion time of 30 s);

[0037] Figure 12 The graph shows the blood routine data of the original PMP membrane and the modified membrane prepared in Example 4 (immersion time of 30 s);

[0038] Figure 13 This is a graph showing the in vitro carbon dioxide removal data of the original PMP membrane and the modified membrane prepared in Example 4 (immersion time of 30 s);

[0039] Figure 14 This is a schematic diagram of a gas flux testing device for a gas exchange membrane.

[0040] Figure 15 This is a graph showing the gas permeability data of the original PMP membrane, the modified membrane prepared in Example 4 (immersion time of 30 s), and the modified membrane prepared in the comparative example. Detailed Implementation

[0041] The following embodiments further illustrate the content of the present invention, but should not be construed as limiting the present invention. Any modifications and substitutions made to the methods, steps, or conditions of the present invention without departing from the essence of the invention are within the scope of the present invention. Example

[0042] (1) Synthesis of ZIF-8-NH2: 1.5 g zinc nitrate hexahydrate, 6.0 g 2-methylimidazole and 0.3 g 2-aminobenzimidazole were dissolved in 100 mL methanol and stirred at room temperature for 2 h. After the reaction was completed, the precipitate was centrifuged at 10000 r / min. The precipitate was washed 3-5 times with methanol and pure water by alternating centrifugation. Finally, the washed precipitate was dried at 70℃ for 24 h to obtain ZIF-8-NH2 nanoparticles.

[0043] (2) Preparation of Pebax casting solution: Mix 2 g Pebax, 17 g ethanol and 3 mL pure water and heat in an oil bath at 85°C for 5 h.

[0044] (3) Preparation of modification solution: Take 0.3 g of ZIF-8-NH2 nanoparticles synthesized in step (1) and disperse them in 10 g of Pebax casting solution. Sonicate for 10 min to make them evenly dispersed. The mass ratio of ZIF-8-NH2 nanoparticles to Pebax in Pebax casting solution is 1:1.

[0045] (4) Preparation of ZIF-8-NH2 / Pebax@PMP composite membrane: Cut 15 cm * 15 cm PMP hollow fiber membranes and immerse them in the modification solution for 10 s, 20 s, 30 s, 40 s and 50 s respectively. Then dry them in an oven for 24 h to obtain the modified composite membrane. Example

[0046] (1) Synthesis of ZIF-8-NH2: Same as in Example 1;

[0047] (2) Preparation of Pebax casting solution: Same as in Example 1;

[0048] (3) Preparation of modification solution: Take 0.3 g of ZIF-8-NH2 nanoparticles synthesized in step (1) and disperse them in 12.5 g of Pebax casting solution. Sonicate for 10 min to make them evenly dispersed. The mass ratio of ZIF-8-NH2 nanoparticles to Pebax in Pebax casting solution is 1:1.25.

[0049] (4) Preparation of ZIF-8-NH2 / Pebax@PMP composite membrane: Same as in Example 1. Example

[0050] (1) Synthesis of ZIF-8-NH2: Same as in Example 1;

[0051] (2) Preparation of Pebax casting solution: Same as in Example 1;

[0052] (3) Preparation of modified solution: Take 0.3 g of ZIF-8-NH2 nanoparticles synthesized in step (1) and disperse them in 16.67 g of Pebax casting solution. Sonicate for 10 min to make them evenly dispersed. The mass ratio of ZIF-8-NH2 nanoparticles to Pebax in Pebax casting solution is 1:1.67.

[0053] (4) Preparation of ZIF-8-NH2 / Pebax@PMP composite membrane: Same as in Example 1. Example

[0054] (1) Synthesis of ZIF-8-NH2: Same as in Example 1;

[0055] (2) Preparation of Pebax casting solution: Same as in Example 1;

[0056] (3) Preparation of modification solution: Take 0.3 g of ZIF-8-NH2 nanoparticles synthesized in step (1) and disperse them in 25 g of Pebax casting solution. Sonicate for 10 min to make them evenly dispersed. The mass ratio of ZIF-8-NH2 nanoparticles to Pebax in Pebax casting solution is 1:2.5.

[0057] (4) Preparation of ZIF-8-NH2 / Pebax@PMP composite membrane: Same as in Example 1. Example

[0058] (1) Synthesis of ZIF-8-NH2: Same as in Example 1;

[0059] (2) Preparation of Pebax casting solution: Same as in Example 1;

[0060] (3) Preparation of modification solution: Take 0.3 g of ZIF-8-NH2 nanoparticles synthesized in step (1) and disperse them in 50 g of Pebax casting solution. Sonicate for 10 min to make them evenly dispersed. The mass ratio of ZIF-8-NH2 nanoparticles to Pebax in Pebax casting solution is 1:5.

[0061] (4) Preparation of ZIF-8-NH2 / Pebax@PMP composite membrane: Same as in Example 1.

[0062] Comparative Example

[0063] (1) Synthesis of ZIF-8: 1.5 g zinc nitrate hexahydrate and 6.0 g 2-methylimidazole were dissolved in 100 mL methanol and stirred at room temperature for 2 h. After the reaction was completed, the precipitate was centrifuged at 10000 r / min. The precipitate was washed 3-5 times with alternating centrifugation with methanol and pure water. Finally, the washed precipitate was dried at 70℃ for 24 h to obtain ZIF-8 nanoparticles.

[0064] (2) Preparation of Pebax casting solution: Same as in Example 1;

[0065] (3) Preparation of modification solution: Take 0.3 g of ZIF-8 nanoparticles synthesized in step (1) and disperse them in 25 g of Pebax casting solution. Sonicate for 10 min to make them evenly dispersed. The mass ratio of ZIF-8 nanoparticles to Pebax in Pebax casting solution is 1:2.5.

[0066] (4) Preparation of ZIF-8 / Pebax@PMP composite membrane: Cut 15 cm * 15 cm PMP hollow fiber membrane, immerse it in the modification solution for 30 s, and then dry it in an oven for 24 h to obtain the modified composite membrane.

[0067] Related performance tests

[0068] Gas flux test:

[0069] A hollow fiber membrane of a certain length is placed in a self-made mold. At room temperature, pure gas is introduced into the mold, such as... Figure 14 The pressure was then adjusted to 1 bar. The gas permeation flux was measured using a soap bubble flow meter.

[0070] A section of hollow fiber membrane with a smooth surface was selected and placed into a self-made membrane module. At room temperature, pure gas at 0.1 MPa was introduced, and the flux of different gases was measured using a soap bubble flow meter. The gas flux was calculated as shown in Equation 2-1:

[0071] (2-1)

[0072] In the formula, J i gas i The permeation rate, in mL / (cm²) 2 (min·bar), v Gas permeation rate (cm) 3 ), S m The effective area of ​​the membrane (cm²) 2 ), t The time (in minutes) for the gas to pass through the membrane. Δp This represents the pressure difference (bar) across the membrane.

[0073] 1. The gas selectivity test results of the modified composite membrane ZIF-8-NH2 / Pebax@PMP prepared in Examples 1-5 are shown in the figure. Figure 3-7 As can be seen from the corresponding figure, when the mass ratio of ZIF-8-NH2 nanoparticles to Pebax remains unchanged, as the immersion time of the PMP membrane in the modification solution increases, the flux of the modified membrane gradually decreases, and its CO2 / O2 selectivity shows a trend of first increasing and then decreasing.

[0074] When the mass ratio of ZIF-8-NH2 nanoparticles to Pebax in the Pebax casting solution is 1:2.5 and the soaking time is 30s (prepared in Example 4), the modified membrane exhibits the highest CO2 / O2 selectivity, reaching 6.58, which is approximately 571% higher than that of the original PMP membrane.

[0075] 2. The ZIF-8-NH2 / Pebax@PMP composite membrane with the highest CO2 / O2 selectivity, prepared under the conditions of immersion time of 30 s and mass ratio of ZIF-8-NH2 to Pebax of 1:2.5 disclosed in Example 4, was subjected to subsequent performance tests (the modified membrane is referred to in the corresponding picture).

[0076] Figure 1 Infrared analysis results of the original PMP membrane, the composite membrane (Pebax) prepared based on Pebax casting solution, the composite membrane (ZIF-8 / Pebax) prepared based on unfunctionalized ZIF-8 in the comparative example, and the modified membrane.

[0077] Figure 2 The images show electron micrographs of the original PMP membrane and the modified membrane. It can be seen from the images that a uniform coating is formed on the surface of the modified membrane without causing damage to the internal structure of the membrane.

[0078] Figure 8 The results of the protein adsorption test of the original PMP membrane and the modified membrane are shown in the figure. It can be seen from the figure that the protein adsorption of the modified membrane is reduced by 58% compared with that of the original membrane.

[0079] Figure 9 The results of the hemolysis rate test of the original PMP membrane and the modified membrane are shown. The hemolysis rate of the modified membrane decreased by 73% compared with that of the original membrane.

[0080] Figure 10 The results of the coagulation time test of the original PMP membrane and the modified membrane are shown. The coagulation time of the modified membrane increased by 38% compared with that of the original membrane.

[0081] Figure 11 The results of platelet adhesion tests on the original PMP membrane (left) and the modified membrane (right) clearly show that the platelet adhesion of the modified membrane is significantly reduced compared to the original PMP membrane.

[0082] Figure 12 The blood routine data of the original PMP membrane and the modified membrane are shown. It can be clearly seen that the number of white blood cells, red blood cells and platelets in the blood incubated with the modified membrane is not significantly reduced compared with the original blood. This indicates that the modified membrane does not damage the blood components and has good biocompatibility.

[0083] Figure 13 The results of carbon dioxide removal tests on the original and modified PMP membranes are shown. It is clearly evident that over time, the pH value and HCO3 level of blood treated with both membranes increased. - The concentrations of all membranes decreased, but the trend of change was more pronounced with the modified membrane, indicating that the modified membrane achieved a higher CO2 removal rate compared to the original PMP membrane. Therefore, the experiment demonstrates that the MOF-modified PMP hollow fiber membrane disclosed in this application exhibits high selective adsorption performance for CO2 / O2, excellent carbon dioxide removal performance, and good blood compatibility and biocompatibility, making it suitable for ECCO2R systems and beneficial for improving the membrane lung's ability to extract CO2 from human blood.

[0084] Figure 15The graph shows the gas permeation flux and selectivity test results of the original PMP membrane and two modified membranes (ZIF-8-NH2 on the horizontal axis refers to the ZIF-8-NH2 / Pebax@PMP composite membrane prepared in Example 4 with an immersion time of 30s, and ZIF-8 refers to the ZIF-8 / Pebax@PMP composite membrane prepared based on un-amino-functionalized MOF in the comparative example). As can be seen from the graph, the ZIF-8-NH2 / Pebax@PMP composite membrane has a 183.6% higher selectivity than the ZIF-8 / Pebax@PMP composite membrane, indicating that the amino-functionalized ZIF-8 has a more significant advantage in improving the selectivity of CO2 / O2.

[0085] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. However, the above description is merely a specific embodiment of the present invention, and the technical features of the present invention are not limited thereto. Any other embodiments derived by those skilled in the art without departing from the technical solution of the present invention should be covered within the patent scope of the present invention.

Claims

1. The application of MOF-modified composite membranes in ECCO2R systems, characterized in that, When used for CO2 / O2 separation, the composite membrane can improve CO2 / O2 selectivity and enhance the biocompatibility of membranes used in ECCO2R systems. The preparation method of the MOF-modified composite membrane is as follows: S1. Synthesize amino-functionalized ZIF-8 nanoparticles, denoted as ZIF-8-NH2; S2. Preparation of Pebax casting solution: Mix Pebax, ethanol and pure water and heat in an oil bath; S3. Preparation of modified solution: Disperse the ZIF-8-NH2 synthesized in step S1 in the casting solution prepared in step S2 by ultrasonic dispersion; S4. Immerse the PMP hollow fiber membrane in the modified solution prepared in step S3, remove it and dry it to obtain the composite membrane, denoted as ZIF-8-NH2 / Pebax@PMP.

2. The application as described in claim 1, characterized in that, In step S1, the steps for synthesizing ZIF-8-NH2 are as follows: soluble zinc salt, 2-methylimidazole, and 2-aminobenzimidazole are dissolved in an organic solvent, stirred to react, centrifuged, washed, and dried.

3. The application as described in claim 2, characterized in that, In step S1, the organic solvent is methanol or ethanol, and the soluble zinc salt is zinc nitrate hexahydrate; The mass-to-volume ratio of soluble zinc salt, 2-methylimidazole, 2-aminobenzimidazole to organic solvent is 1.5 g:(1.5-6) ​​g:(0.3-1.2) g:100 mL; Centrifugation conditions were 10000 r / min for 10 min; The drying process is carried out at 60-80℃ for 24 hours.

4. The application as described in claim 1, characterized in that, In step S2, the ratio of Pebax, ethanol, and pure water is (1-2) g:17 g:3 mL, and the heating conditions are: oil bath heating, 80-90℃, 4-6 h.

5. The application as described in claim 1, characterized in that, In step S3, the amount of ZIF-8-NH2 used is 0.1-0.5 g, and the mass ratio of ZIF-8-NH2 to Pebax in the casting solution is 1:(1-5).

6. The application as described in claim 5, characterized in that, In step S4, the PMP hollow fiber membrane is immersed in the modified solution for 10-50 seconds.

7. The application as described in claim 6, characterized in that, The mass ratio of ZIF-8-NH2 to Pebax in the casting solution is 1:2.5, and the immersion time of the PMP hollow fiber membrane in the modified solution is 30 s.

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