Zeolite-like porous framework material for efficiently removing carbon dioxide in closed space and preparation method of zeolite-like porous framework material

Abstract

The invention relates to the technical field of adsorption materials and environment and energy, and provides a zeolite-like porous framework material for efficiently removing carbon dioxide in a closed space and a preparation method of the zeolite-like porous framework material, the structural general formula of the zeolite-like porous framework material is [M (CN) 6] xM'yAz, the zeolite-like porous frame material is composed of a dodecahedron-like pore cage structure, each pore cage is provided with 12 pore windows, the 12 pore windows comprise 6 hexagonal pore windows and 6 quadrilateral pore windows, and when the temperature T is in the range of 273-333 K, 0.5 D (CO2) < = D4 < = D (CO2) < = D6 < = 2D (CO2) < = Dc < = 4D (CO2) is satisfied; wherein D (CO2) is the dynamic diameter of CO2 molecules at normal temperature, D4 is the diameter of the quadrilateral hole window, D6 is the diameter of the hexagonal hole window, and Dc is the diameter of the hole cage; the zeolite-like porous framework material selectively adsorbs ultra-low-concentration carbon dioxide (1000-10000 ppm) in a closed space, and extremely high CO2 low-pressure adsorption capacity can be achieved with extremely low regeneration energy consumption.

Description

Technical Field

[0001] This invention relates to the technical fields of adsorption materials and environment and energy, specifically to a zeolite-like porous framework material for efficiently removing carbon dioxide from confined spaces and its preparation method. Background Technology

[0002] Air purification systems in enclosed spaces are crucial for the safety of people within them. Enclosed spaces (such as spacecraft and submarines) are places with low air circulation, where pollutants, including carbon dioxide, typically accumulate. If left untreated, CO2 concentrations rise rapidly, posing a serious threat to human health. Typically, CO2 concentrations in enclosed spaces range from 1000 to 10000 ppm. At around 5000 ppm, people may experience headaches and stuffiness; prolonged exposure can lead to decreased cognitive function and increased respiratory rate. At around 10000 ppm, symptoms can escalate to nausea, dizziness, and even loss of consciousness. Therefore, implementing carbon dioxide removal technology in enclosed spaces helps improve air quality and protect human health.

[0003] Currently, relatively mature technologies for carbon dioxide removal in confined spaces include: using chemical solvents (such as amine solutions) to absorb carbon dioxide, but these have problems such as high regeneration energy consumption, short lifespan, severe equipment corrosion, and easy chemical decomposition, which will further increase the cost of carbon capture; and using consumable materials such as lithium hydroxide (LiOH) to remove CO2 gas through chemical reaction with CO2, but the reactants are non-renewable and have a single function, making them unsuitable for use in submarines and spacecraft during long-term operations (Norfleet W & Horn W. Habitation (Elmsford). 9, 67-78 (2003); Arieli R, Eynan M, Arieli Y & Abramovich A. Aviat Space Environ Med. 80, 561-564 (2009).).

[0004] Therefore, the physical adsorption mechanism based on renewable solid adsorbents provides an energy-saving alternative to traditional processes. The core of the physical adsorption mechanism lies in the design and selection of the adsorbent. The variable conditions in a confined space (complex gas composition, humidity level, and temperature) place higher demands on the removal of trace amounts of carbon dioxide. Among them, inorganic zeolite molecular sieve materials, due to the competitive adsorption between CO2 and water, experience a significant decrease in CO2 adsorption performance without dehumidification of the air (Merel, J., Clausse, M. & Meunier, F. Ind. Eng. Chem. Res. 47, 209-215 (2008)). Metal-organic frameworks (MOFs) are a class of porous crystalline materials formed by the coordination self-assembly of metal ions or metal clusters with organic ligands. They possess advantages such as strong structural designability and easy functionalization of pore surfaces, and are an advanced porous material that has emerged and developed in recent years. With reasonable topology design and selection of functional sites, it can be applied to the capture of CO2 at ultra-low concentrations (<0.5%), and has the advantages of easy control of adsorption performance, low regeneration energy consumption and high cycle stability.

[0005] Although many benchmark materials for capturing low-concentration carbon dioxide have been reported, the following problems still exist: the inherent contradiction between high CO2 low-pressure adsorption capacity and low CO2 regeneration energy consumption—ultraporous materials, due to their pore size matching CO2 molecules, face challenges. Pore ​​confinement can achieve various strong thermodynamic effects on CO2, resulting in high low-pressure adsorption capacity. However, the excessively strong thermodynamic effects also lead to high regeneration energy consumption. While macroporous materials have low regeneration energy consumption, their excessively large pore size... This results in insufficient host-guest interactions, thus sacrificing low-pressure adsorption capacity. Furthermore, most materials also suffer from insufficient moisture resistance and low stability. M., Cheung, O. & Xu, C. Dalton Trans. 52, 1841-1856 (2023); Chakraborty, D., Yurdusen, A., Mouchaham, G., Nouar, F. & Serre, C. Adv. Funct. Mater. 2309089 (2023)). Summary of the Invention

[0006] To address the technical challenges described above, this invention provides a zeolite-like porous framework material for efficiently removing carbon dioxide from confined spaces and its preparation method. This invention constructs small-sized pores within a large-sized pore cage material; the "large-sized" refers to... The small size refers to By precisely controlling the hexagonal pore window to match the CO2 kinetic diameter, small-sized carbon dioxide molecules can be accurately identified through the molecular sieve effect, and highly electrostatic carbon dioxide binding sites can be introduced. This ingeniously designed and constructed zeolite-like porous framework material with free positively charged cations and a cage-like structure combines the advantages of traditional microporous materials, macroporous materials, and highly electrostatic porous materials through the synergistic effect of these features. This improves the low-pressure CO2 adsorption capacity of the material while achieving low-energy regeneration. At room temperature, the zeolite-like porous framework material of this invention exhibits an adsorption capacity ≥2 mmol g for 10000 ppm CO2. -1 For 5000 ppm CO2, the adsorption capacity is ≥1 mmol g. -1 This invention utilizes a zeolite-like porous framework material prepared by hydrothermal recrystallization as a physical adsorbent to selectively adsorb ultra-low concentrations of carbon dioxide (1000–10000 ppm) in a confined space, achieving extremely high CO2 low-pressure adsorption capacity with extremely low regeneration energy consumption.

[0007] The technical solution of the present invention is as follows:

[0008] This invention provides a zeolite-like porous framework material, wherein the general structural formula of the zeolite-like porous framework material is [M(CN)6]. x M′ y A z , of which [M(CN)6] 4- [Ru(CN)6] 4- Or [Fe(CN)6] 4- , 1≤x≤6; M′ is any one or more divalent transition metal ions, 1≤y≤8; A is H + NH4 + The cations are any one or more monovalent or divalent cations from alkali metal ions and alkaline earth metal ions, where 1 ≤ z ≤ 6; when A is a monovalent cation, 4x - 2y - z = 0 is satisfied; when A is a divalent cation, 2x - yz = 0 is satisfied; the zeolite-like porous framework material is composed of a dodecahedral cage structure, each cage having 12 windows, including 6 hexagonal windows and 6 quadrilateral windows. When the temperature T is in the range of 273 to 333 K, 0.5D(CO2) ≤ D4 ≤ D(CO2) ≤ D6 ≤ 2D(CO2) ≤ D c ≤4D(CO2).

[0009] Where D(CO2) is the kinetic diameter of the CO2 molecule at room temperature. D4 is the diameter of the quadrilateral window, calculated as twice the shortest distance from the atoms forming the quadrilateral window to the geometric center. D6 is the diameter of the hexagonal window, calculated as twice the shortest distance from the atoms forming the hexagonal window to the geometric center. c The diameter of the cage is calculated as twice the shortest distance from the atoms that make up the cage to the geometric center.

[0010] The dodecahedral-like porous cage structure refers to a spatial geometry composed of atoms and chemical bonds, which has six hexagonal geometric faces and six quadrilateral geometric faces (corresponding to six hexagonal apertures and six quadrilateral apertures). The dodecahedral-like porous cage structure can be obtained by X-ray diffraction (XRD) testing, and the structure of the porous framework material can be obtained by reconstructing, fitting, or refining based on the test data.

[0011] The diameter of the quadrilateral perforated window in the dodecahedral-like perforated cage structure is smaller than the CO2 kinetic diameter. This zeolite-like porous framework, which cannot facilitate CO2 transport but only serves as a supporting structure, has hexagonal pores that match the kinetic diameter of CO2 molecules. It can precisely identify small-sized carbon dioxide molecules through the molecular sieve effect. Simultaneously, multiple positively charged cations within the framework can engage in multiple strong electrostatic interactions with linear CO2 molecules, which are negatively charged at both ends. By changing the types of divalent transition metal ions (M′) and cations (A), not only can the diameter of the pores and windows, as well as the BET surface area, be controlled, but also the number and intensity of interactions between the framework sites and CO2 molecules can be adjusted. Through the synergistic effect of these features, ultra-high selectivity for low-concentration CO2 adsorption is ultimately achieved. The zeolite-like porous framework material described above exhibits an adsorption capacity ≥2 mmol g for 10,000 ppm CO2. -1 For 5000 ppm CO2, the adsorption capacity is ≥1 mmol g. -1 The amount of gas adsorbed was measured at room temperature.

[0012] The porous material exhibits high crystallinity, ensuring the integrity of its periodic framework structure, allowing gas molecules to selectively enter the dodecahedral-like pore cages only through the hexagonal windows. The zeolite-like porous framework material exhibits a saturated adsorption capacity ≤0.5 mmol g for gases other than CO2 (O2, Ar, He, N2) in the air. -1 The amount of gas adsorbed was measured at room temperature.

[0013] Due to its large diameter Unlike ultraporous materials with micro- and nano-pores, dodecahedral-like porous cages cannot form a strong pore confinement effect on adsorbed CO2 molecules. Compared to ultraporous materials, dodecahedral-like porous cages offer higher degrees of freedom for CO2 and allow it to be in a more dispersed state, resulting in lower heat of adsorption. This resolves the inherent contradiction of simultaneously achieving high low-pressure adsorption capacity and low regeneration energy consumption. The zeolite-like porous framework material described above exhibits a saturated CO2 adsorption capacity ≥3 mmol g. -1 The zeolite-like porous framework material described above has an adsorption heat of ≤45 kJ / mol for CO2. -1 .

[0014] Furthermore, in the above technical solution, the molar ratio between elements M, C, N, M′, and A in the general structural formula is 1:(4~8):(4~8):(1~3):(0.5~2); the molar ratio of the elements can be tested by a combination of one or more methods such as atomic absorption spectrometry (AAS), inductively coupled plasma emission spectrometry (ICP), X-ray fluorescence spectrometry (XRF), organic elemental analysis, and energy dispersive X-ray spectroscopy (EDS).

[0015] Preferably, the XRD pattern of the zeolite-like porous framework material has a single peak at 2θ = 16.0 ± 2°, 19.3 ± 2°, 21.3 ± 2° and 24.1 ± 2°; and a double peak at 2θ = 13.0 ± 2°; the XRD pattern is measured under normal temperature and pressure and air environment.

[0016] Preferably, when the temperature T = 298K, the perforated cage structure satisfies 0.6D(CO2) ≤ D4 ≤ 0.8D(CO2) ≤ D6 ≤ 1.5D(CO2) ≤ D c ≤4D(CO2).

[0017] Preferably, the zeolite-like porous framework material exhibits a uniform and regular square block morphology, with a D50 particle size of 10 nm to 150 μm;

[0018] Preferably, the BET specific surface area of ​​the zeolite-like porous framework material is 300–800 m². 2 g -1 ;

[0019] Preferably, the synthesized zeolite-like porous framework material is [Ru(CN)6]Zn 3 / 2 K, named ZJU-202a-K, exhibits a CO2 adsorption capacity of 2.16 mmol g at 296 K and 0.01 bar (10000 ppm). -1 (48.38cm 3 g -1At 0.005 bar (5000 ppm), the CO2 adsorption capacity was 1.44 mmol g. -1 (32.26cm 3 g -1 The separation selectivity for carbon dioxide / nitrogen (1 / 99, v / v) was 2771, and the heat of adsorption for CO2 was 39.3 kJ / mol. -1 The heat of adsorption of N2 is 17.7 kJ / mol. -1 It has both high CO2 low-pressure adsorption capacity and low adsorption heat, which is very beneficial for the rapid regeneration of the adsorbent.

[0020] Furthermore, the zeolite-like porous framework material exhibits excellent chemical and hydrothermal stability, maintaining good structural integrity even after immersion in acid, alkali, and aqueous solutions, and also after high-temperature treatment. The PXRD diffraction peak position changes by no more than 1°, and the CO2 adsorption loss at 5000ppm and 10000ppm does not exceed 5%. The pH range of the acid and alkali is 1–14, and the temperature range of the high-temperature treatment is 25℃–300℃.

[0021] Furthermore, based on the Ideal Adsorption Solution Theory (IAST), the IAST selectivity (Si) of the zeolite-like porous framework material for CO2 / N2, CO2 / Ar, CO2 / He, and CO2 / O2 with a volume ratio (v / v) of 1 / 99 was calculated. ads ≥1000;

[0022]

[0023] Where q1 and q2 are the mole fractions of components 1 and 2 in the adsorbed phase, and p1 and p2 are the mole fractions of components 1 and 2 in the gas phase, where component 1 is CO2 and component 2 is other gases (N2, Ar, He, O2). The Ideal Adsorption Solution Theory (IAST) refers to the adsorption isotherm equation that can be derived from thermodynamic laws when the mixture within the adsorption layer is treated as an ideal solution during the adsorption of a mixed gas.

[0024] This invention also provides a method for preparing a zeolite-like porous framework material, wherein the method for preparing the zeolite-like porous framework material is a hydrothermal recrystallization method, and the specific steps are as follows:

[0025] (1) Preliminary crystallization: Mix a 0.01–2 M salt solution containing divalent transition metal ions M′ with a 0.01–2 M solution containing [M(CN)6]. 4- The salt solutions of the divalent transition metal ion M′ are mixed with [M(CN)6]. 4-The volume ratio of the salt solution is 1:(1~5); the resulting mixture is stirred at room temperature for 1~2 hours at a stirring rate of 100~300rpm to produce a solid precipitate, which is then allowed to stand at 25℃~150℃ for 2~72 hours, and then filtered to obtain the initial crystal material.

[0026] (2) Hydrothermal recrystallization: The initial crystal material obtained in step (1) is immersed in a salt solution containing cation A and hydrothermally recrystallized by storing it at 25℃~200℃ for 1~72 hours. The precipitate is filtered and separated, and washed with water and ethanol to obtain the zeolite-like porous material before activation.

[0027] (3) Solvent removal: The zeolite-like porous material obtained in step (2) is exchanged multiple times in a low-boiling-point organic solvent and then filtered to obtain a powder product. Each time is at least 3 hours apart. Then the solvent molecules in the powder product are desorbed to obtain the zeolite-like porous framework material.

[0028] Compared to previously reported single-crystallization methods, the hydrothermal recrystallization method provided by this invention enables secondary crystallization of the initial crystals in a hydrothermal environment, thereby optimizing crystal quality and preparing highly crystalline porous framework materials, thus achieving superior CO2 selective adsorption performance. The zeolite-like porous framework material prepared by the hydrothermal recrystallization method exhibits a uniform and regular square block morphology with a D50 particle size of 10 nm to 150 μm. The zeolite-like porous framework material prepared by the hydrothermal recrystallization method has complete framework coordination and an extremely low defect rate. The BET specific surface area of ​​the zeolite-like porous framework material is 300 to 800 m². 2 g -1 The specific surface area can be determined based on various isothermal adsorption-desorption curves of 77KN2, 87KAr, 196K CO2 and 273K CO2; the isothermal adsorption-desorption curves do not have the hysteresis loops unique to defective materials.

[0029] Preferably, in step (1), the divalent transition metal ion is selected from Zn. 2+ Fe 2+ Co 2+ Cu 2+ Ni 2+ Cd 2+ Any one or more of the following; preferably, the solvent of the salt solution is selected from one or more of water, alcohols and nitriles, more preferably a mixture of water and ethanol; preferably, the standing temperature in step (1) is 60-120°C; the standing time is preferably 2-48h;

[0030] Preferably, in step (2), the concentration of the salt solution of cation A is ≥0.5M, preferably 2M; preferably, the solvent of the salt solution of cation A is selected from one or more of water, alcohols and nitriles, more preferably water; preferably, the mass ratio of the initial crystal material to the salt solution of cation A is 1:(20-150); preferably, the hydrothermal recrystallization temperature is preferably 60-120℃; and the recrystallization time is preferably 2-48h.

[0031] Preferably, the low-boiling-point organic solvent in step (3) is selected from one or more alcohols and ketones, more preferably anhydrous ethanol; preferably, in step (3), the solvent molecule desorption method is a combination of one or more of the following methods: decompression, heating or gas purging; more preferably, the decompression method is to keep the vacuum degree of the environment in which the material is located ≤100Pa; more preferably, the heating method is to keep the temperature of the environment in which the material is located between 25℃ and 200℃; more preferably, the gas purging method uses a combination of one or more low-polarity gases such as nitrogen, argon, helium, air or steam; preferably, the solvent removal time in step (3) is 3 to 48 hours.

[0032] The present invention also provides a CO2 adsorbent comprising the zeolite-like porous framework material as described above or the zeolite-like porous framework material prepared by the preparation method described above.

[0033] The present invention also provides a method for adsorbing CO2, wherein the adsorbent described above is contacted with CO2 gas.

[0034] The present invention also provides a CO2 adsorption device, comprising the adsorbent as described above, or using the adsorption method as described above; preferably, the adsorption device includes, but is not limited to, an adsorption bed, an adsorption pipeline, and an adsorption chamber.

[0035] The present invention also provides an application for adsorbing CO2, using the adsorbent as described above, or the adsorption method as described above, or the adsorption device as described above; preferably, the application for adsorbing CO2 is specifically the efficient removal of ultra-low concentration CO2 in a confined space, wherein the ultra-low concentration CO2 is 1000 to 10000 ppm.

[0036] Furthermore, the gas composition in the enclosed space is air containing 1000-10000 ppm CO2 (other components are O2, Ar, He, and N2).

[0037] Furthermore, the aforementioned zeolite-like porous framework material is used as a physical adsorbent, and the contact method with air containing 1000–10000 ppm CO2 is any one of fixed-bed adsorption, moving-bed adsorption, fluidized-bed adsorption, or rotary adsorption, specifically including the following steps:

[0038] (1) At the adsorption temperature and pressure, air containing 1000 to 10000 ppm CO2 is introduced into a container containing adsorbent. Non-CO2 components (O2, Ar, He, N2) in the air preferentially penetrate the adsorption container.

[0039] (2) When the carbon dioxide outlet concentration is detected to be the same as the inlet concentration, stop the supply of mixed raw material gas;

[0040] (3) By using a combination of one or more methods such as decompression, heating or gas purging, the adsorbed carbon dioxide gas group is decomposed and adsorbed until no CO2 gas is detected at the outlet, which proves that the adsorbent has been regenerated and steps (1)(2)(3) can be repeated.

[0041] Furthermore, the adsorption temperature was 273–473 K, the adsorption pressure was 0–10 bar, and the gas flow rate was 0.1–5000 mL / min. -1 .

[0042] Preferably, the contact method is fixed-bed adsorption, and the adsorption temperature is 273K to 323K. The separation effect is optimal within this adsorption temperature range.

[0043] Preferably, a gas purging method is used to achieve material regeneration and recycling, with the gas used being 10 mL / min. -1 Helium gas.

[0044] The beneficial effects of this invention are as follows:

[0045] (1) The zeolite-like porous framework material described in this invention has high crystallinity, ensuring the integrity of its periodic framework structure (dodecahedral-like porous cage structure and pore windows); compared to pore sizes larger than... The macroporous material, with its dodecahedral cage structure, not only has multiple hexagonal windows matching the size of CO2 molecules, but also can accurately identify small carbon dioxide molecules through the molecular sieve effect. In the process of removing carbon dioxide in a closed space, compared with other gases in the air (O2, Ar, He, N2), carbon dioxide with a smaller kinetic diameter can pass through the windows smoothly, thus achieving accurate identification and capture of carbon dioxide in the air. Moreover, the material has multiple free cations in the cages, and carbon dioxide molecules with larger quadrupole moments can undergo strong multi-electrostatic interactions with the free cations. The synergistic effect of the dodecahedral cage structure and cation sites can achieve selective and large-volume adsorption under low pressure.

[0046] (2) The zeolite-like porous framework material described in this invention, compared to materials with pore sizes smaller than... The ultraporous material has a large-size pore cage structure Unable to form an extremely strong pore confinement effect, this material retains the advantage of low regeneration energy consumption of macroporous materials, not exceeding 45 kJ / mol. -1 Therefore, it exhibits high regeneration efficiency under the same regeneration conditions. Specifically, ZJU-202a-K achieves a CO2 adsorption capacity of 2.16 mmol g under the conditions of 296 K, 0.01 bar (10000 ppm). -1 (48.38cm 3 g -1 At 0.005 bar (5000 ppm), the CO2 adsorption capacity was 1.44 mmol g. -1 (32.26cm 3 g -1 The heat of adsorption for carbon dioxide is 39.3 kJ / mol. -1 The heat of adsorption is the lowest among all reported low-concentration carbon dioxide capture materials, overcoming the inherent contradiction between high low-pressure adsorption capacity and low regeneration energy consumption.

[0047] (3) The zeolite-like porous framework material described in this invention is prepared by hydrothermal recrystallization. Compared with the previously reported primary crystallization method, it enables the initial crystals to undergo secondary crystallization in a hydrothermal environment. The prepared zeolite-like porous framework material exhibits a uniform and regular square block morphology with suitable specific surface area and particle size. The obtained zeolite-like porous framework material has complete framework coordination and extremely low defect rate, thereby optimizing crystal quality, preparing highly crystalline porous framework materials, and thus achieving better CO2 selective adsorption performance.

[0048] (4) The zeolite-like porous framework material described in this invention can be synthesized in a green manner using water and ethanol as solvents, by mixing a salt solution containing divalent transition metal ions M′ with [M(CN)6]. 4- The initial crystalline material is obtained by heating a salt solution containing ions. This initial material is then mixed with a free cation salt solution of a certain concentration, and the target porous framework material can be obtained by hydrothermal recrystallization at a relatively low synthesis temperature. This synthesis method is easy to implement, requires minimal equipment, uses a green and environmentally friendly metal source, and has advantages such as high economic feasibility and ease of large-scale production.

[0049] In summary, the highly crystalline zeolite-like porous framework material used in this invention not only exhibits high low-pressure adsorption capacity and selectivity but also low heat of adsorption, successfully overcoming the technical challenges faced by currently reported materials in removing carbon dioxide in confined spaces. Using the zeolite-like porous framework material described in this invention as an adsorbent, it can selectively adsorb large quantities of ultra-low concentrations of carbon dioxide (1000–10000 ppm) in confined spaces and can be regenerated with low energy consumption. Furthermore, its mild and environmentally friendly synthesis method and high stability promise for practical applications. This invention provides a new methodological guide for the efficient capture of low-concentration carbon dioxide in confined spaces and has broad application prospects. Attached Figure Description

[0050] Figure 1 The image shows the crystal structure of the material in Example 1. Figure 1 (a) in the diagram is a schematic diagram of the overall structure. Figure 1 (b) in the diagram is a schematic diagram of the perforated cage and window.

[0051] Figure 2 The image shows the PXRD pattern of the material in Example 1.

[0052] Figure 3 This is a SEM image of the material in Example 1.

[0053] Figure 4 The graph shows the total nitrogen adsorption curve at 77K for the material in Example 1.

[0054] Figure 5 This is a single-component isothermal adsorption curve of carbon dioxide and nitrogen for the material in Example 1 at 296 K and 0–1 bar.

[0055] Figure 6 This is a single-component isothermal adsorption curve of carbon dioxide for the material in Example 1 at 296 K and 0–0.01 bar.

[0056] Figure 7 The image shows the IAST selectivity of the material in Example 1 for a mixture of CO2 / N2 (1 / 99, v / v) and CO2 / N2 (0.5 / 99.5, v / v) at 296 K.

[0057] Figure 8 This is a thermal diagram of the adsorption of carbon dioxide and nitrogen by the material in Example 1 at 296K.

[0058] Figure 9 This is a comparison graph of the 5000ppm CO2 adsorption capacity and CO2 adsorption heat between the material in Example 1 and other reported reference materials.

[0059] Figure 10The material in Example 1 was subjected to temperatures of 298 K, 1 bar, and 10 mL min. -1 The dynamic penetration test curve of CO2 / N2 under dry conditions of 0.5 / 99.5 (v / v) is shown in the figure.

[0060] Figure 11 The material in Example 1 was subjected to temperatures of 298 K, 1 bar, and 10 mL min. -1 The dynamic penetration test curve of 1 / 99 (v / v) CO2 / N2 under dry conditions.

[0061] Figure 12 The images show the PXRD patterns of the material in Example 1 after immersion in acid, alkali, and aqueous solutions.

[0062] Figure 13 This is a single-component isothermal adsorption curve of carbon dioxide after the material in Example 1 was soaked in acid, alkali and aqueous solution.

[0063] Figure 14 The PXRD patterns of the material in Example 1 from room temperature to 300°C are shown. Detailed Implementation

[0064] The present invention will be further illustrated below with reference to the embodiments. However, these embodiments do not limit the scope of protection of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

[0065] The detection method of the present invention is as follows:

[0066] The crystal structure of the zeolite-like porous framework material described in this invention can be obtained by single-crystal X-ray diffraction (SCXRD) or powder X-ray diffraction (PXRD) in air, vacuum, or inert gas atmosphere; wherein the radiation source for single-crystal X-ray diffraction is Cu-Kα or Mo-Kα radiation; and the radiation source for powder X-ray diffraction is Cu-Kα radiation. The scanning range is 2–45°, and the scanning speed is 5° / min. -1 .

[0067] The dodecahedral porous cage structure and pore window structure of the zeolite-like porous framework material described in this invention can be obtained through X-ray diffraction (XRD) testing. The structure of the porous framework material is then obtained by reconstructing, fitting, or refining the test data. Testing of the dodecahedral porous cage structure: The crystal structure data of the material obtained through XRD testing is used to determine the dodecahedral porous cage structure of the material using crystal structure processing software. The atoms and chemical bonds are displayed using a ball-and-stick model. The crystal structure processing software includes, but is not limited to, Diamond software, Materials Studio software, and Olex software.

[0068] The diameter of the quadrilateral window (D4), the diameter of the hexagonal window (D6), and the diameter of the perforated cage (D...) c The crystal structure can be obtained by measuring the crystal structure using crystal structure analysis software based on the crystal structure measured by single crystal X-ray diffraction (SCXRD) or powder X-ray diffraction (PXRD).

[0069] The molar ratio of elements can be determined by a combination of one or more methods, such as atomic absorption spectroscopy (AAS), inductively coupled plasma emission spectroscopy (ICP), X-ray fluorescence spectroscopy (XRF), organic elemental analysis, and energy-dispersive X-ray spectroscopy (EDS).

[0070] BET specific surface area can be determined by carbon dioxide, nitrogen or argon molecules;

[0071] The particle size and square block morphology of the zeolite-like porous framework material were tested by one or more of the following methods: scanning electron microscopy (SEM), optical microscopy, laser particle size analyzer, and particle size analyzer.

[0072] Calculation of IAST selectivity: The adsorption selectivity of the material for CO2 / N2 mixed gas was calculated based on the ideal adsorption solution theory (IAST). For the specific calculation method, please refer to (Myers, A.L. et al., AIChE J., 1965, 11, 121–127).

[0073] Example 1

[0074] 6 mmol of zinc sulfate, 200 mL of deionized water, 9 mL of ethanol, and 4 mmol of potassium hexacyanorubate were added sequentially to a reaction vessel. The resulting mixture was stirred at room temperature for 60 minutes and then stored in a 60°C oven for 24 hours. The resulting precipitate was filtered to obtain the initial crystal material. The initial crystal material was then immersed in a 2M potassium chloride solution and stored in a 120°C oven for 48 hours. The resulting precipitate was filtered and washed with water and ethanol to obtain the homogeneous crystal material ZJU-202-K before activation. The homogeneous crystal material was exchanged multiple times in anhydrous ethanol, with each exchange at least 3 hours apart, and then vacuum dried sequentially at room temperature and 100°C for 12 hours to obtain ZJU-202a-K (a is an abbreviation for activated, i.e., the activated sample) for gas adsorption testing, with the structural formula [Ru(CN)6]2Zn3K2.

[0075] The crystal structure of the material is shown in Figure 1 The zeolite-like porous framework material prepared in Example 1 was obtained by X-ray diffraction (XRD). Based on the test data, reconstruction, fitting, or refinement confirmed that it consisted of a dodecahedral porous cage structure. This dodecahedral porous cage structure refers to a spatial geometry composed of atoms and chemical bonds, having six hexagonal and six quadrilateral geometric faces. Each cage has 12 pores, including six hexagonal and six quadrilateral pores corresponding to the six hexagonal and six quadrilateral geometric faces of the cage. When the temperature T is in the range of 273–333 K, the cage diameter (D) c )for The diameter of the hexagonal window (D6) is The diameter of the quadrilateral window (D4) is Satisfies 0.6D(CO2) <D4<0.8D(CO2)<D6<1.5D(CO2)<D c <3.5D(CO2), where D(CO2) is This indicates that CO2 molecules can only diffuse into the pore cage through the hexagonal pore windows and cannot enter through the quadrilateral pore windows. Furthermore, each hexagonal pore window only allows one CO2 molecule to enter, thus enabling ultra-microporous molecular sieving. Each pore cage can adsorb multiple CO2 molecules, which is beneficial for achieving high adsorption capacity of macroporous materials.

[0076] See PXRD pattern Figure 2 The XRD pattern of the zeolite-like porous framework material prepared in Example 1 shows single peaks at 2θ = 16.5°, 19.7°, 21.8°, and 23.9°, and double peaks at 2θ = 13.7°. In the structural formula, the molar ratio of elements Ru, C, N, Zn, and K is 1:6:6:1.5:1.

[0077] To characterize the morphology of ZJU-202-K, SEM images of the sample were taken, as shown below. Figure 3 As shown, the zeolite-like porous framework material exhibits a uniform and regular square block morphology, with a D50 particle size of 10 nm to 150 μm.

[0078] To characterize the specific surface area of ​​ZJU-202a-K, a nitrogen total adsorption test was performed at 77K. The results are shown in [Figure number missing]. Figure 4 According to calculations, the Brunauer-Emmett-Teller (BET) specific surface area of ​​ZJU-202a-K is 654 m². 2 g -1 The pore volume is 0.27 cm³. 3 g -1 .

[0079] To characterize the adsorption performance of ZJU-202a-K for carbon dioxide and nitrogen, single-component adsorption curves for carbon dioxide and nitrogen were tested at 296 K. The results are shown in [Figure number missing]. Figure 5 and Figure 6 The CO2 adsorption capacity was 4.98 mmol g under the conditions of 296 K and 1 bar. -1 The adsorption capacity of N2 was 0.32 mmol g. -1 The CO2 adsorption capacity was 2.16 mmol g under the conditions of 296 K, 0.01 bar (10000 ppm). -1 The CO2 adsorption capacity at 0.005 bar (5000 ppm) is 1.44 mmol g. -1 This demonstrates the high low-pressure adsorption capacity of ZJU-202-K.

[0080] To more intuitively demonstrate the separation effect of ZJU-202a-K on low-concentration carbon dioxide, the carbon dioxide / nitrogen separation selectivity at 296K for carbon dioxide concentrations of 5000 ppm and 10000 ppm was calculated, respectively. The results are shown below. Figure 7 The IAST selectivity of ZJU-202a-K for carbon dioxide / nitrogen at a concentration of 5000 ppm is 2859, and the IAST selectivity of ZJU-202a-K for carbon dioxide / nitrogen at a concentration of 10000 ppm is 2771.

[0081] To further determine the regeneration energy consumption of ZJU-202a-K, the adsorption heats of carbon dioxide and nitrogen at 296K were calculated respectively. Figure 8 The heat of adsorption for carbon dioxide is 39.3 kJ / mol. -1 The heat of adsorption of nitrogen is 17.7 kJ / mol. -1The relatively low heat of carbon dioxide adsorption is highly beneficial for the recycling and regeneration of materials. Based on the adsorption capacity and heat of carbon dioxide adsorption at 5000 ppm, such as... Figure 9 As shown, by comparing with benchmark materials, it is demonstrated that ZJU-202a-K successfully overcomes the inherent contradiction between high low-pressure adsorption capacity and low regeneration energy consumption.

[0082] To simulate the CO2 capture process in a real confined space, and considering that nitrogen content is highest in the air, a dynamic fixed-bed breakthrough experiment was used to evaluate the actual separation effect of ZJU-202a-K on mixed gases with volume ratios of 0.5 / 99.5 CO2 / N2 and 1 / 99 CO2 / N2. Figure 10 As shown, for 5000 ppm CO2 at 948 min cm -3 The CO2 dynamic adsorption capacity was calculated to be 1.4 mmol g. -1 (51.8cm 3 cm -3 );like Figure 11 As shown, for 10000ppm CO2 at 650 min cm -3 Upon exposure, the dynamic CO2 adsorption capacity was 1.9 mmol g. -1 (72.5cm 3 cm -3 In this invention, the volumetric adsorption capacity (Q) V cm 3 cm -3 ) and mass adsorption capacity (Q) M mmol g -1 The conversion formula for () is:

[0083] Q V =Q M ×V m ×D cry

[0084] Q V The volumetric adsorption capacity of the material, in cm³. 3 cm -3 Q M The mass adsorption capacity of the material is expressed in mmol / g. -1 V M It is the molar volume of a gas, with units of Lmol. -1 Under standard conditions, V M =22.4 Lmol -1 ;D cry It is the crystal density of the material, measured in g / cm³. -1 The zeolite-like porous framework material of this invention has a crystal density of 1.7–2 g / cm³. -1 .

[0085] To characterize the chemical and thermal stability of ZJU-202-K, thermogravimetric analysis (TGA), PXRD patterns after immersion in acid, alkali, and aqueous solutions, CO2 adsorption curves, and PXRD patterns after heat treatment at 25℃–300℃ were tested. The results are shown in [Figure number missing]. Figure 12 , Figure 13 and Figure 14 The structural collapse of ZJU-202-K after 510℃ demonstrates its excellent thermal stability. ZJU-202-K maintains its structural integrity even after immersion in acid, alkali, and aqueous solutions, with almost no loss of PXRD characteristic peaks and CO2 adsorption capacity, indicating its excellent chemical stability. This superior stability is highly advantageous for use in practical confined spaces.

[0086] Example 2

[0087] Compared with the preparation and detection methods of Example 1, the hydrothermal recrystallization temperature of 120°C in Example 1 was adjusted to 25°C and 200°C respectively, thereby preparing ZJU-202a-K(25) and ZJU-202a-K(200). Both materials exhibit single peaks at 2θ = 16.5°, 19.7°, 21.8°, and 23.9°, and double peaks at 2θ = 13.7°. The differences in diffraction peak positions between these materials and the materials in Example 1 are less than 0.2°, demonstrating the consistency of their structures. The molar ratios of Ru, C, N, Zn, and K in ZJU-202a-K(25) are 1:5.98:5.99:1.51:0.99, and those in ZJU-202a-K(200) are 1:6.02:5.98:1.49:1.01. The differences in molar ratios between these materials and the materials in Example 1 are less than 1:0.1:0.1:0.1:0.1, demonstrating the consistency of their compositions. According to 77K... The BET specific surface area was tested by N2 adsorption curves, and the BET specific surface area of ​​ZJU-202a-K(25) was 641 m². 2 g -1 The BET specific surface area of ​​ZJU-202a-K(200) is 659 m². 2 g -1 The BET specific surface area differs from that of the material in Example 1 by less than 3%. In summary, this demonstrates that the material described in this invention can be prepared within the hydrothermal recrystallization temperature range of 25–200°C.

[0088] Example 3

[0089] Compared with the preparation and detection methods of Example 1, Example 3 adjusted the hydrothermal recrystallization time of 48 hours in Example 1 to 2 hours and 72 hours, respectively, thereby preparing ZJU-202a-K(2) and ZJU-202a-K(72). Both materials exhibit single peaks at 2θ = 16.5°, 19.7°, 21.8°, and 23.9°, and double peaks at 2θ = 13.7°. The differences in diffraction peak positions between these materials and the PXRD pattern of the material in Example 1 are less than 0.1°, demonstrating the consistency of their structures. The molar ratios of Ru, C, N, Zn, and K in the composition of ZJU-202a-K(2) are 1:6.04:5.95:1.50:0.97, and those in the composition of ZJU-202a-K(200) are 1:6.06:5.97:1.48:1.02. The differences in molar ratios between these materials and the composition of the material in Example 1 are less than 1:0.1:0.1:0.1:0.1, demonstrating the consistency of their compositions. According to 77K... The BET specific surface area was measured by N2 adsorption curves, and the BET specific surface area of ​​ZJU-202a-K(2) was 632 m². 2 g -1 The BET specific surface area of ​​ZJU-202a-K(72) is 649 m². 2 g -1 The BET specific surface area differs from that of the material in Example 1 by less than 4%. In summary, this demonstrates that the material described in this invention can be prepared within a hydrothermal recrystallization time range of 2–72 hours.

[0090] Example 4

[0091] Compared with the preparation and detection methods of Example 1, in Example 4, the potassium ion concentration 2M in Example 1 was adjusted to 0.5M and the supersaturation concentration (s, solution supersaturation) respectively, thereby preparing ZJU-202a-K(0.5) and ZJU-202a-K(s). Both materials exhibit single peaks at 2θ = 16.5°, 19.7°, 21.8°, and 23.9°, and double peaks at 2θ = 13.7°. The differences in diffraction peak positions between these materials and the PXRD pattern of the material in Example 1 are less than 0.15°, demonstrating the consistency of their structures. The molar ratios of Ru, C, N, Zn, and K in the composition of ZJU-202a-K(0.5) are 1:6.07:5.99:1.44:1, and those in the composition of ZJU-202a-K(s) are 1:5.97:6.08:1.52:1.01. The differences in molar ratios between these materials and the composition of the material in Example 1 are both less than 1:0.1:0.1:0.1:0.1, demonstrating the consistency of their compositions. According to 77K... The BET specific surface area was measured by N2 adsorption curves, and the BET specific surface area of ​​ZJU-202a-K(0.5) was 629 m². 2 g -1 The BET specific surface area of ​​ZJU-202a-K(s) is 661 m². 2 g -1 The BET specific surface area of ​​the material in Example 1 differs from that in Example 1 by less than 5%. In summary, this demonstrates that the material described in this invention can be prepared using a cation solution with a molar concentration greater than 0.5 M.

[0092] Similarly, the materials prepared in Examples 2-5 exhibit similar performance to the materials in Example 1 when used for carbon dioxide removal in confined spaces. Utilizing their specific pore cage and window structure, they can accurately identify small carbon dioxide molecules compared to other gases in the air (O2, Ar, He, N2), achieving selective and large-volume adsorption under low pressure with extremely low heat of adsorption. Therefore, the experimental results of the embodiments of this invention show that zeolite-like porous materials can achieve high low-pressure carbon dioxide capture with low regeneration energy consumption, and are expected to be truly applied to the field of efficient capture of low-concentration carbon dioxide in confined spaces.

[0093] Comparative Example 1

[0094] The only difference between Comparative Example 1 and Example 1 in terms of preparation and detection methods is that the stirring rate at room temperature before static storage was 50 rpm. Specifically, 6 mmol of zinc sulfate, 200 mL of deionized water, 9 mL of ethanol, and 4 mmol of potassium hexacyanoruburate were added sequentially to a reaction vessel. The resulting mixture was stirred at 50 rpm at room temperature for 60 minutes, and then statically stored in a 60°C oven for 24 hours. The resulting precipitate was filtered to obtain the initial crystalline material. The initial crystalline material was then immersed in a 2M potassium chloride solution and stored in a 120°C oven for 48 hours. The resulting precipitate was filtered and washed with water and ethanol to obtain the unactivated material. The unactivated material was exchanged multiple times in anhydrous ethanol, with each exchange at least 3 hours apart, and then vacuum dried sequentially at room temperature and 100°C for 12 hours to obtain a porous material for gas adsorption testing. Due to the low stirring rate, the raw materials were unevenly distributed in the liquid-phase reaction system, resulting in numerous defects in the initial crystallized product and a decrease in product crystallinity. The PXRD pattern of the material showed significant broadening of the diffraction peaks, exhibiting a broadened peak at 2θ = 13.7° instead of the double peaks seen in Example 1. Furthermore, the material's 296K CO2 adsorption performance decreased by more than 10% compared to the material in Example 1. Therefore, it is evident that without the room-temperature stirring process following the preliminary crystallization step described in this invention, the zeolite-like porous framework material with the characteristics and properties described in this invention cannot be obtained.

[0095] Comparative Example 2

[0096] The only difference between Comparative Example 2 and Example 1 in terms of preparation and detection methods is the absence of the hydrothermal recrystallization step. Specifically, 6 mmol of zinc sulfate, 200 mL of deionized water, 9 mL of ethanol, and 4 mmol of potassium hexacyanorubicate were added sequentially to a reaction vessel. The resulting mixture was stirred at room temperature for 60 minutes and then stored in a 60°C oven for 24 hours. The resulting precipitate was filtered to obtain a homogeneous crystalline material. This homogeneous crystalline material was then exchanged multiple times in anhydrous ethanol, with each exchange spaced at least 3 hours apart. It was then vacuum-dried sequentially at room temperature and 100°C for 12 hours to obtain a porous material for gas adsorption testing. The PXRD pattern of the material showed significant broadening of diffraction peaks, exhibiting a broadened peak at 2θ = 13.7°, unlike the double peaks of the material in Example 1. The diffraction peak intensities were significantly reduced, with the intensity at the same position being less than half that of the material in Example 1. The BET specific surface area of ​​the material, measured by 77KN2 adsorption, was less than 500 m². 2 g -1 The yield was reduced by more than 20% compared to the material in Example 1. Therefore, it can be seen that without the hydrothermal recrystallization step described in this invention, the zeolite-like porous framework material with the characteristics and properties described in this invention cannot be obtained.

[0097] Comparative Example 3

[0098] The only difference between Comparative Example 3 and Example 1 in terms of preparation and detection methods is the absence of a solvent removal step. Specifically, 6 mmol of zinc sulfate, 200 mL of deionized water, 9 mL of ethanol, and 4 mmol of potassium hexacyanorubate were added sequentially to a reaction vessel. The resulting mixture was stirred at room temperature for 60 minutes and then stored in a 60°C oven for 24 hours. The resulting precipitate was filtered to obtain the initial crystal material. This initial crystal material was then immersed in a 2M potassium chloride solution and stored in a 120°C oven for 48 hours. The resulting precipitate was filtered, washed with water and ethanol, and the homogeneous crystal material ZJU-202-K before activation was obtained. The BET specific surface area of ​​the material, as measured by 77KN2 adsorption, was less than 100 m². 2 g -1 The 296K CO2 adsorption performance of the material decreased by more than 80% compared to the material in Example 1. This demonstrates that the zeolite-like porous framework material with the characteristics and properties described in this invention cannot be obtained without the solvent removal step described in this invention. The above embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A zeolite-like porous framework material, characterized by: The zeolite-like porous framework material structure has a general formula of [M(CN)6] x M' y A z , wherein [M(CN)6] 4- is [Ru(CN)6] 4- or [Fe(CN)6] 4- , 1≤x≤6; M' is any one or more of divalent transition metal ions, 1≤y≤8; A is any one or more of H + , NH4 + , alkali metal ions, alkaline earth metal ions, monovalent or divalent cations, 1≤z≤6; when A is a monovalent cation, 4x-2y-z=0 is satisfied; when A is a divalent cation, 2x-y-z=0 is satisfied; the zeolite-like porous framework material is composed of a dodecahedral-like pore cage structure, each pore cage has 12 pore windows, the 12 pore windows include 6 hexagonal pore windows and 6 quadrilateral pore windows, and 0.5D(CO2)≤D4≤D(CO2)≤D6≤2D(CO2)≤D c ≤4D(CO2) is satisfied when the temperature T is in the range of 273-333K. wherein D(C02) is the kinetic diameter of a CO2 molecule at room temperature D4 is the diameter of a tetragonal aperture, D6 is the diameter of a hexagonal aperture, D c is the diameter of the pore cage; Preferably, the diameter of the hole cage is Preferably, the diameter of the hexagonal aperture is Preferably, the diameter of the quadrilateral aperture is Preferably, the zeolite-like porous framework material has a uniform and regular square block morphology, and a D50 particle size of 10 nm to 150 μm. Preferably, the zeolite-like porous framework material has a BET specific surface area of 300 to 800 m2 / g 2 g -1 ; Preferably, the zeolite-like porous framework material has good chemical stability and hydrothermal stability, and can maintain good structural integrity after being soaked in acid, alkali and aqueous solution, and can maintain good structural integrity after high-temperature treatment, with a change in PXRD pattern diffraction peak position of not more than 1°, and a loss of CO2 adsorption amount of not more than 5% at 5000 ppm and 10000 ppm; the pH range of the acid and alkali is 1 to 14, and the temperature range of the high-temperature treatment is 25°C to 300°C. Preferably, in the structural general formula, the molar ratio of elements M, C, N, M', A is 1:(4-8):(4-8):(1-3):(0.5-2). Preferably, the XRD pattern of the zeolite-like porous framework material has a single peak at 2θ = 16.0 ± 2°, 19.3 ± 2°, 21.3 ± 2° and 24.1 ± 2°, and a double peak at 2θ = 13.0 ± 2°.

2. The zeolite-type porous framework material of claim 1, wherein: When the temperature T = 298 K, the pore cage structure satisfies 0.6D(CO2)≤D4≤0.8D(CO2)≤D6≤1.5D(CO2)≤D c ≤4D(CO2).

3. The zeolite-type porous framework material of claim 1, wherein: The divalent transition metal ion is selected from any one or more of Zn 2+ , Fe 2+ , Co 2+ , Cu 2+ , Ni 2+ , Cd 2+ .

4. The zeolite-like porous framework material of claim 1, wherein: The IAST selectivity (S ads ) of the zeolite-like porous framework material for CO2 / N2, CO2 / Ar, CO2 / He, CO2 / O2 with a volume ratio (volume / volume, abbreviated as v / v) of 1 / 99 calculated according to the ideal adsorbed solution theory (IAST) is S ads )≥1000; Wherein q1 and q2 are the mole fractions of components 1 and 2 in the adsorption phase, p1 and p2 are the mole fractions of components 1 and 2 in the gas phase, component 1 is CO2, and component 2 is other gas (N2, Ar, He, O2).

5. The zeolite-like porous framework material of claim 1, wherein: The zeolite-like porous framework material has an adsorption capacity of ≥ 2 mmol g for 10,000 ppm of CO2 -1 an adsorption capacity of ≥ 1 mmol g for 5,000 ppm of CO2 -1 The zeolite-like porous framework material has an adsorption heat for CO2 of ≤ 45 kJ mol -1 .

6. A method of making a zeolite-like porous framework material, characterized by: The preparation method of the porous material is a hydrothermal recrystallization method, and the specific steps are as follows: (1) preliminary crystallization: mixing 0.01-2 M salt solution containing divalent transition metal ion M' with 0.01-2 M salt solution containing [M(CN)6]4-, wherein the volume ratio of the salt solution containing divalent transition metal ion M' to the salt solution containing [M(CN)6]4- is 1:(1-5); the resulting mixture is stirred at room temperature for 1-2 hours, the resulting mixture is stirred at room temperature for 1-2 hours, the stirring rate is 100-300 rpm, solid precipitate is produced, and then the mixture is allowed to stand at 25°C-150°C for 2-72 hours, and the initial crystal material is obtained by filtration separation; 4- 4- (2) secondary crystallization: mixing 0.01-2 M salt solution containing divalent transition metal ion M' with 0.01-2 M salt solution containing [M(CN)6]4-, wherein the volume ratio of the salt solution containing divalent transition metal ion M' to the salt solution containing [M(CN)6]4- is 1:(1-5); the resulting mixture is stirred at room temperature for 1-2 hours, the resulting mixture is stirred at room temperature for 1-2 hours, the stirring rate is 100-300 rpm, solid precipitate is produced, and then the mixture is allowed to stand at 25°C-150°C for 2-72 hours, and the secondary crystal material is obtained by filtration separation;​ (2) Hydrothermal recrystallization: the initial crystal material obtained in step (1) is soaked in a salt solution containing cation A, and hydrothermal recrystallization is carried out by storing at 25°C to 200°C for 1 to 72 hours, and the obtained precipitate is separated by filtration, washed with water and ethanol, to obtain a zeolite-like porous material before activation; (3) Solvent removal: the zeolite-like porous material obtained in step (2) is exchanged in a low-boiling-point organic solvent for multiple times, and the powder product is obtained after filtration, with a time interval of at least 3 hours, and then the solvent molecules in the powder product are desorbed, to obtain the zeolite-like porous framework material; Preferably, in step (1), the divalent transition metal ion is selected from any one or more of Zn 2+ , Fe 2+ , Co 2+ , Cu 2+ , Ni 2+ , and Cd 2+ ; preferably, the solvent of the salt solution is selected from one or more of water, alcohols, and nitriles, more preferably a mixture of water and ethanol; preferably, the temperature of the standing in step (1) is preferably 60 to 120 °C; and the standing time is preferably 2 to 48 h. Preferably, in step (2), the salt solution of cation A has a concentration of ≥0.5 M, preferably 2 M; preferably, the solvent of the salt solution of cation A is selected from one or more of water, alcohol and nitrile, more preferably water; preferably, the mass ratio of the initial crystal material to the salt solution of cation A is 1:(20-150); preferably, the hydrothermal recrystallization temperature is preferably 60-120°C; and the recrystallization time is preferably 2-48 h. Preferably, the low-boiling organic solvent in step (3) is selected from one or more of alcohols, ketones, more preferably anhydrous ethanol; preferably, in step (3), the method for desorbing the solvent molecules is a combination of one or more of reduced pressure, elevated temperature, or gas purging; more preferably, the reduced pressure method is to maintain the vacuum degree of the environment of the material at ≤ 100 Pa; more preferably, the elevated temperature method is to maintain the temperature of the environment of the material at 25-200°C; more preferably, the gas purging method uses a combination of one or more of nitrogen, argon, helium, air, or steam; preferably, the time for removing the solvent in step (3) is 3-48 hours.

7. A CO2 adsorbent comprising the zeolite-like porous framework material of any one of claims 1-5 or prepared by the method of claim 6.

8. A method of adsorbing CO2, characterized by, Contacting the adsorbent of claim 7 with CO2 gas.

9. A CO2 adsorption device, characterized by, An adsorption device comprising the adsorbent of claim 7, or using the adsorption method of claim 8; preferably, the adsorption device includes but is not limited to an adsorption bed, an adsorption pipeline, or an adsorption chamber.

10. Use of an adsorbent for adsorbing CO2, characterized in that Using the adsorbent of claim 7, or using the adsorption method of claim 8, or using the adsorption device of claim 9; preferably, the application of adsorbing CO2 is specifically the efficient removal of ultra-low concentration CO2 in a closed space, and the ultra-low concentration CO2 is 1000-10000 ppm.

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