A zeolite molecular sieve material with high CO2 capture efficiency, its preparation method and application
By introducing highly polarizable metal cations and alkylamines into zeolite molecular sieves, the problem of inaccurate pore size control was solved, achieving efficient CO2 capture and separation, improving CO2 adsorption capacity and selectivity, and avoiding pore blockage and high energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NINGBO INST OF MATERIALS TECH & ENG CHINESE ACAD OF SCI
- Filing Date
- 2023-12-22
- Publication Date
- 2026-07-31
AI Technical Summary
Existing zeolite molecular sieve materials suffer from imprecise pore size control, high cost, and instability during CO2 adsorption, making it difficult to achieve efficient CO2 capture and separation.
By introducing highly polarizable metal cations such as zinc or cobalt through ion exchange and modifying them with organic ligands of alkylamines, the pore size of zeolite molecular sieves can be adjusted and specific adsorption sites can be introduced, thereby improving the CO2 adsorption capacity and selectivity.
This method significantly improves the adsorption capacity and selectivity of zeolite molecular sieves for CO2, reduces their adsorption capacity for other gases, solves the problem of pore blockage, and is simple, low-energy, and produces no secondary pollution.
Smart Images
Figure CN117963937B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of zeolite molecular sieve modification, and relates to a zeolite molecular sieve material with high-efficiency CO2 capture function, its preparation method and application. Background Technology
[0002] Currently, various porous adsorbent materials with high CO2 adsorption performance have been developed, such as custom-sized metal-organic frameworks and amine-grafted solid adsorbents. However, their high cost and relative instability limit their practical applications. In contrast, zeolite materials, due to their low cost, high specific surface area, and high thermal stability, are among the most promising materials for carbon dioxide adsorption.
[0003] The size selectivity of zeolite crystal structures allows only molecules matching the size and shape of the zeolite channels to enter, thus achieving a kind of molecule "screening." However, in practical systems, the molecular size that needs to be distinguished is often less than 0.1 nm. For example, in separating CO2 / N2, the pore size of the adsorbent should be between... (CO2) to (N2) range. Although pore size can be altered by adjusting synthesis conditions, this method is typically imprecise and unstable. Therefore, surface modification of the zeolite is necessary to achieve more precise pore size control.
[0004] To address the aforementioned technical challenges, the use of functionalization methods to improve the CO2 adsorption performance of zeolite molecular sieves is attracting widespread attention. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing a zeolite molecular sieve material with high-efficiency CO2 capture function. This zeolite molecular sieve material can selectively adsorb CO2, while the adsorption of other gases such as nitrogen and methane is very small, and it can increase the adsorption of CO2, thereby achieving the purpose of high-efficiency capture and separation of CO2.
[0006] The objective of this invention is achieved through the following technical solution: a method for preparing a zeolite molecular sieve material with high-efficiency CO2 capture function, the preparation method specifically including the following steps:
[0007] S1. Ion exchange: Weigh dry zeolite molecular sieve, add an aqueous solution of metal cations and carry out ion exchange reaction. After the ion exchange reaction is completed, filter to obtain ion-exchanged zeolite molecular sieve.
[0008] S2. Preparation of ligand solution: Weigh alkylamine and add it to methanol solution. Stir thoroughly to ensure uniform distribution of the ligands to obtain the ligand solution.
[0009] S3. Organic ligand modification: The ion-exchange zeolite molecular sieve obtained in step S1 is added to the ligand solution obtained in step S2. After the reaction, the solution is filtered to obtain a zeolite molecular sieve material with high CO2 capture function.
[0010] The present invention uses the above preparation method to synthesize a zeolite molecular sieve material with high efficiency CO2 capture function. The material uses zeolite molecular sieve as a carrier, loads metal cations and then introduces alkylamine for modification. The metal cations are introduced by exchanging with the cations in the zeolite molecular sieve framework using ion exchange method, and the organic ligands are introduced into the molecular sieve by the interaction between metal ions and N atoms.
[0011] Preferably, in step S1, the metal cation in the aqueous solution is either zinc or cobalt. We introduced highly polarizable metal cations into the molecular sieve through ion exchange, which increased the dispersion potential energy of the zeolite material and enhanced its adsorption capacity for CO2.
[0012] Preferably, in step S1, the zeolite molecular sieve is selected from one of NaY zeolite molecular sieve, SSZ-13 zeolite molecular sieve, and ZSM-5 zeolite molecular sieve.
[0013] Preferably, in step S1, the zeolite molecular sieve is a nano-sized zeolite molecular sieve or a micro-sized zeolite molecular sieve. This invention employs zeolite molecular sieves of these grades. Nano-sized pores exhibit strong selectivity for molecular size and shape, enabling efficient adsorption of small molecules such as gases, ions, and organic matter. Furthermore, nano-sized zeolites possess a large specific surface area, which is beneficial for adsorption and catalytic reactions. Micro-sized molecular sieves, on the other hand, have moderately sized pores, suitable for adsorbing and separating medium-sized molecules. Moreover, micro-sized molecular sieves can provide abundant active sites, facilitating the adsorption of guest molecules.
[0014] Preferably, in step S1, the zeolite molecular sieve is in powder or granular form. This invention uses zeolite molecular sieves of the aforementioned shape, wherein powdered zeolite has advantages such as uniformity, ease of mixing and dispersion, and the highest specific surface area, which makes it perform excellently in adsorption and catalysis processes.
[0015] Preferably, in step S1, the ion exchange reaction is selected from at least one of vacuum stirring, ultrasonic oscillation, or microwave-assisted ion exchange.
[0016] Preferably, in step S2, the alkylamine is selected from ethylenediamine, diethanolamine, and propylamine, and the ratio of alkylamine to metal cation is (0.5-4):1. Different amino ligands are introduced into the molecular sieve through the coordination of the metal cation with the N atom. Alkylamines are often used as chelating ligands for CO2 capture. The secondary amine group formed after ethylenediamine coordinates with equilibrium cations such as cobalt can form weak CO2 adsorption sites, increasing the adsorption capacity while reducing the high adsorption heat caused by the primary amine.
[0017] Preferably, in step S3, the reaction temperature is 60°C and the reaction time is 2 hours. By using the above-mentioned reaction temperature and time, this invention ensures coordination between the ligand and the equilibrium cation, while avoiding pore blockage caused by spontaneous entanglement of amino groups at excessively high temperatures.
[0018] The second objective of this invention is to provide a zeolite molecular sieve material with high CO2 capture efficiency, which is prepared by the above-described method.
[0019] The third objective of this invention is to provide an application of a zeolite molecular sieve material with a high-efficiency CO2 capture function, wherein the zeolite molecular sieve material is used to capture and separate CO2 in flue gas and other industrial waste gases.
[0020] Compared with the prior art, the present invention has the following advantages:
[0021] 1. Increased CO2 adsorption capacity of molecular sieve materials: After ion exchange, metal cations introduce ions with higher polarizability, such as cobalt, which improves the adsorption capacity of molecular sieve materials for CO2. In addition, by introducing specific adsorption sites such as amino and hydroxyl groups, the adsorption capacity can be increased by reacting with CO2.
[0022] 2. Improved selectivity of molecular sieve materials for CO2: After ion exchange, because the radius of cobalt ions is larger than that of sodium ions in the original structure, the supercage pore size in the zeolite structure is reduced from... Reduce to Meanwhile, the introduction of organic ligands also changed the pore size of the molecular sieve, which reduced the adsorption capacity of the zeolite molecular sieve for other gases, thereby increasing the selective adsorption capacity of the molecular sieve for CO2.
[0023] 3. Existing technologies for modifying zeolite molecular sieves mainly include ion exchange and grafting methods. Compared with the direct grafting method, the preparation method of this invention first performs ion exchange treatment, introducing metal cations that can interact with nitrogen atoms into the pores of the zeolite molecular sieve. Based on the molar content of metal cations in the molecular sieve measured by X-ray fluorescence spectrometry (XRF), an appropriate amount of organic ligand can be added, improving the problem of large-area clogging of the molecular sieve pores. Furthermore, compared with the ion exchange method, the introduction of organic ligands solves the problem of the lack of specific adsorption sites in the ion exchange method. In addition, the preparation method provided by this invention has the advantages of being simple and easy to implement, low energy consumption, high efficiency, and not generating secondary pollution. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the preparation process of the zeolite molecular sieve material with high CO2 capture function of the present invention;
[0025] Figure 2 This is a schematic diagram of the CO2 selective adsorption of the zeolite molecular sieve material with high-efficiency CO2 capture function of the present invention;
[0026] Figure 3 These are the XRD spectra of Na-Y and Co-Y in Examples 1 to 4 of the present invention, Co-Y-EN-2 in Example 2, Co-Y-EN-5 in Example 3, and Co-Y-EN-7 in Example 4;
[0027] Figure 4 These are SEM images of the Co-Y samples from Examples 1 to 6 of this invention;
[0028] Figure 5 These are adsorption performance diagrams of Co-Y and Co-Y-EN series zeolite molecular sieve materials prepared in Examples 1-4 and Example 1 of the present invention. Detailed Implementation
[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0030] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0031] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This application specification and embodiments are merely exemplary.
[0032] like Figure 1 As shown, the first objective of this invention is to provide a method for preparing zeolite molecular sieve materials with high-efficiency CO2 capture function, specifically including the following steps:
[0033] S1. Ion exchange: Weigh dry zeolite molecular sieve, add an aqueous solution of metal cations and carry out ion exchange reaction. After the ion exchange reaction is completed, filter to obtain ion-exchanged zeolite molecular sieve.
[0034] S2. Preparation of ligand solution: Weigh alkylamine and add it to methanol solution. Stir thoroughly to ensure uniform distribution of the ligands to obtain the ligand solution.
[0035] S3. Organic ligand modification: The ion-exchange zeolite molecular sieve obtained in step S1 is added to the ligand solution obtained in step S2. After the reaction, the solution is filtered to obtain a zeolite molecular sieve material with high CO2 capture function.
[0036] In a specific embodiment, in step S1, the metal cation in the aqueous solution is either zinc or cobalt ions. We introduced highly polarizable metal cations into the molecular sieve through ion exchange, thereby increasing the dispersion potential energy of the zeolite material and enhancing its adsorption capacity for CO2.
[0037] In a specific implementation, in step S1, the zeolite molecular sieve is selected from one of NaY zeolite molecular sieve, SSZ-13 zeolite molecular sieve, and ZSM-5 zeolite molecular sieve.
[0038] In a specific implementation, in step S1, the zeolite molecular sieve is a nano-sized zeolite molecular sieve or a micron-sized zeolite molecular sieve.
[0039] In a specific implementation, in step S1, the zeolite molecular sieve is in powder or granular form.
[0040] In a specific embodiment, in step S1, the ion exchange reaction is selected from at least one of vacuum stirring, ultrasonic oscillation, or microwave-assisted ion exchange.
[0041] In a specific embodiment, in step S2, the alkylamine is selected from ethylenediamine, diethanolamine, and propylamine, and the ratio of the alkylamine to the metal cation is (0.5-4):1. Different amino ligands are introduced into the molecular sieve through the coordination of the metal cation with the N atom.
[0042] In a specific implementation, the reaction temperature in step S3 is 60°C.
[0043] The second objective of this invention is to provide a zeolite molecular sieve material with high CO2 capture efficiency, which is prepared by the above-described method.
[0044] The third objective of this invention is to provide an application of a zeolite molecular sieve material with a high-efficiency CO2 capture function, wherein the zeolite molecular sieve material is used to capture and separate CO2 in flue gas and other industrial waste gases.
[0045] The technical effects of the present invention will be described below with reference to specific embodiments.
[0046] Example 1
[0047] In this embodiment, Na-Y zeolite molecular sieve is used as an example. The Na-Y zeolite molecular sieve is a commercially available Na-Y molecular sieve with sodium ions as the cation. 10g of Na-Y molecular sieve is weighed and added to 200mL of an appropriate concentration of cobalt nitrate aqueous solution. The cobalt ions are exchanged with the cation Na in the structure of the Na-Y zeolite molecular sieve by ion exchange method, so that the cobalt ions are introduced into the channels of the Y zeolite molecular sieve to form Co-Y zeolite molecular sieve material.
[0048] The product was collected by centrifugation and thoroughly dried. 1 g of Co-Y was weighed and added to a methanol solution, followed by an appropriate amount of ethylenediamine. The mixture was reacted at 60°C for 2 hours. The synthesized product was washed three times with methanol to remove the ethylenediamine adhering to its surface, and then dried under vacuum at 120°C for 12 hours. Finally, the Co-Y-EN series molecular sieve was activated at 200°C for adsorption testing.
[0049] The modified Co-Y-EN series zeolite molecular sieve material prepared above was tested. The test results show that the adsorption capacity increased from 2.52 mmol / g to 4.35 mmol / g. At the same time, the selectivity of this material for CO2 / N2 increased to 73.9.
[0050] Example 2
[0051] In the series of molecular sieves prepared in Example 1, the sample obtained when the ratio of ethylenediamine to cobalt ions was 0.5:1 was Co-Y-EN-2. The preparation method was the same as in Example 1, and will not be repeated here.
[0052] Example 3
[0053] In the series of molecular sieves prepared in Example 1, the sample obtained when the ratio of ethylenediamine to cobalt ions was 2:1 was Co-Y-EN-5. The preparation method was the same as in Example 1, and will not be repeated here.
[0054] Example 4
[0055] In the series of molecular sieves prepared in Example 1, the sample obtained when the ratio of ethylenediamine to cobalt ions was 4:1 was Co-Y-EN-7. The preparation method was the same as in Example 1, and will not be repeated here.
[0056] XRD analysis was performed on Na-Y and Co-Y in Examples 1 to 4, Co-Y-EN-2 in Example 2, Co-Y-EN-5 in Example 3, and Co-Y-EN-7 in Example 4. The results are as follows: Figure 3 As shown, it can be seen that as the amount of ligand increases, the pores of the zeolite structure become blocked, indicating that the ligand has successfully entered the zeolite structure.
[0057] The Co-Y samples from Examples 1 to 4 were tested, and the results are as follows: Figure 4 As shown, from Figure 4 It can be seen that the modification process using the present invention is relatively mild, does not significantly damage the morphology of zeolite, and preserves its original tetrahedral structure.
[0058] The adsorption properties of the Co-Y zeolite molecular sieve materials from Examples 1 to 4 and the Co-Y-EN series zeolite molecular sieve materials prepared in Example 1 were tested. The test results are as follows: Figure 5 As shown, the inclusion of small-molecule amino groups enhances the adsorption capacity of zeolite for carbon dioxide. However, when the ratio of ethylenediamine to cobalt ions is greater than 2, the steric hindrance of the ligands and the spontaneous entanglement between amino groups cause pore blockage and increase mass transfer resistance, resulting in a decrease in adsorption performance.
[0059] Example 5
[0060] In this embodiment, H-SSZ-13 zeolite molecular sieve is used as an example. The H-SSZ-13 zeolite molecular sieve is a commercially available H-SSZ-13 molecular sieve with hydrogen ions as the cation. 10g of H-SSZ-13 molecular sieve is weighed and added to 200mL of an appropriate concentration of cobalt nitrate aqueous solution. The cobalt ions are then exchanged with the hydrogen cation in the structure of the H-SSZ-13 zeolite molecular sieve using an ion exchange method, thereby introducing the cobalt ions into the pores of the SSZ-13 zeolite molecular sieve to form Co-SSZ-13 zeolite molecular sieve material.
[0061] The product was collected by centrifugation and thoroughly dried. 1 g of Co-SSZ-13 was weighed and added to a methanol solution, followed by an appropriate amount of ethylenediamine. The mixture was reacted at 60°C for 2 hours. The synthesized product was washed three times with methanol to remove the ethylenediamine adhering to its surface, and then dried under vacuum at 120°C for 12 hours. Finally, the Co-SSZ-13-EN molecular sieve was activated at 200°C for adsorption testing.
[0062] The Co-SSZ-13-EN zeolite molecular sieve material prepared above was tested. The test results showed that the results were similar to those obtained in Example 1. That is, compared with commercial grade SSZ-13 molecular sieve, the modified product showed improved adsorption capacity and selectivity.
[0063] Example 6
[0064] In this embodiment, H-ZSM-5 zeolite molecular sieve is used as an example. The H-ZSM-5 zeolite molecular sieve is a commercially available H-ZSM-5 molecular sieve with sodium ions as the cation. 10g of H-ZSM-5 molecular sieve is weighed and added to 200mL of an appropriate concentration of zinc nitrate aqueous solution. The zinc ions are then exchanged with the cation H in the structure of the H-ZSM-5 zeolite molecular sieve using an ion exchange method. This allows the zinc ions to be introduced into the channels of the ZSM-5 zeolite molecular sieve, forming a Zn-ZSM-5 zeolite molecular sieve material.
[0065] The product was collected by centrifugation and thoroughly dried. 1 g of Zn-ZSM-5 was weighed and added to a methanol solution, followed by an appropriate amount of propylamine. The mixture was reacted at 60°C for 2 hours. The synthesized product was washed three times with methanol to remove the ethylenediamine adhering to its surface, and then dried under vacuum at 120°C for 12 hours. Finally, the Zn-ZSM-5-PA molecular sieve was activated at 200°C for adsorption testing.
[0066] The Zn-ZSM-5-am zeolite molecular sieve material prepared above was tested, and the results were similar to those obtained in Example 1. That is, compared with commercial ZSM-5 molecular sieve, the modified product showed improved adsorption capacity and selectivity.
[0067] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.
Claims
1. A method for preparing a zeolite molecular sieve material with high-efficiency CO2 capture function, characterized in that, The preparation method specifically includes the following steps: S1. Ion exchange: Weigh dry zeolite molecular sieves, add an aqueous solution of metal cations and carry out an ion exchange reaction. After the ion exchange reaction is completed, filter to obtain ion-exchanged zeolite molecular sieves. The zeolite molecular sieves are selected from one of NaY zeolite molecular sieves, SSZ-13 zeolite molecular sieves and ZSM-5 zeolite molecular sieves. S2. Preparation of ligand solution: Weigh alkylamine and add it to methanol solution. Stir thoroughly to ensure uniform distribution of the ligands to obtain the ligand solution. S3. Organic ligand modification: The ion-exchange zeolite molecular sieve obtained in step S1 is added to the ligand solution obtained in step S2. After the reaction, the solution is filtered to obtain a zeolite molecular sieve material with high CO2 capture function. The reaction temperature is 60℃ and the reaction time is 2h. In step S2, the alkylamine is selected from ethylenediamine, diethanolamine and propylamine, and the ratio of alkylamine to metal cation is 2:
1. In step S1, the metal cation in the aqueous solution is either zinc ion or cobalt ion.
2. The method for preparing zeolite molecular sieve material with high-efficiency CO2 capture function as described in claim 1, characterized in that, In step S1, the zeolite molecular sieve is a nano-sized zeolite molecular sieve or a micro-sized zeolite molecular sieve.
3. The method for preparing zeolite molecular sieve material with high-efficiency CO2 capture function as described in claim 1, characterized in that, In step S1, the zeolite molecular sieve is in powder or granular form.
4. The method for preparing zeolite molecular sieve material with high-efficiency CO2 capture function as described in claim 1, characterized in that, In step S1, the ion exchange reaction is selected from at least one of vacuum stirring, ultrasonic oscillation, or microwave-assisted ion exchange.
5. A zeolite molecular sieve material with high-efficiency CO2 capture function, characterized in that, It is prepared by any of the preparation methods described in claims 1-4.
6. An application of a zeolite molecular sieve material with high-efficiency CO2 capture function as described in claim 5, characterized in that, The zeolite molecular sieve material is used to capture and separate CO2 from flue gas and other industrial waste gases.