Moisture-resistant stable blocky cyclodextrin-based metal organic framework material and application thereof

Abstract

The invention discloses a moisture-resistant stable blocky cyclodextrin-based metal organic framework material and application thereof.According to the material, gamma-cyclodextrin and alkali metal ions serve as precursors, an overall blocky porous monomer (gamma-CD-MOF-monolith) is prepared through in-situ growth, then short-time heat treatment is conducted in an inert atmosphere at the temperature of 200-260 DEG C, organic ligands on the surface are partially carbonized, and the moisture-resistant stable blocky cyclodextrin-based metal organic framework material is obtained. A thin layer of amorphous carbon coating is formed while maintaining frame crystallinity and pore structure. Under the conditions of 298K and 100kPa, the CO2 adsorption capacity of the blocky CD-MOF is greater than 60.0 cm < 3 > g <-1 >, and the blocky CD-MOF still keeps gt after being continuously placed for 30 days in an environment with the relative humidity of 90%; the adsorption capacity of CO2 is 80%, and good separation performance and long-term stability are shown in removal of CO2 in natural gas / hydrocarbons. The invention relates to the technical field of porous adsorption materials and gas separation. According to the moisture-resistant and stable blocky cyclodextrin-based metal organic framework material and the application thereof, the process is simple, no binder exists, energy consumption is low, and the moisture-resistant and stable blocky cyclodextrin-based metal organic framework material is suitable for large-scale production and industrial application.

Description

Technical Field

[0001] This invention relates to the field of porous adsorption materials and gas separation technology, specifically to a moisture-resistant and stable bulk cyclodextrin-based metal-organic framework material and its applications. Background Technology

[0002] With the widespread application of hydrocarbon fuels such as natural gas, methane, and ethane in the energy and chemical industries, the removal of carbon dioxide (CO2) during their purification process has received increasing attention. Natural gas and other hydrocarbon gases often contain a certain amount of CO2 impurities, which not only reduces the calorific value of the fuel gas but also causes corrosion problems during transportation and storage (Chem. Commun., 55 (2019) 3219-3222, ACS Appl. Mater. Interfaces, 14 (2022) 26858-26865, Adv. Funct. Mater., 34 (2024) 202312280). Although the existing amine absorption method can remove CO2, it has disadvantages such as high energy consumption, severe equipment corrosion, and complex regeneration processes; while physical absorption is less efficient under low partial pressure conditions, making it difficult to meet the requirements of high-efficiency and energy-saving separation. Therefore, selective CO2 removal based on adsorption has become an important development direction.

[0003] Metal-organic frameworks (MOFs) are considered promising new materials for CO2 adsorption and separation due to their high specific surface area, tunable pore size, and modifiable surface functional groups (Green Chem. Eng., 5 (2024) 187-204, Chem. Eng. J., 449 (2022) 137768). Among them, cyclodextrin-based metal-organic frameworks (CD-MOFs), constructed using natural cyclodextrin ligands, combine the advantages of being environmentally friendly with high CO2 affinity, exhibiting excellent reverse selectivity, especially in CO2 / N2 and CO2 / C2H2 systems. However, CD-MOF materials generally suffer from a serious drawback—extreme sensitivity to water. Its ligand, cyclodextrin, contains a large number of hydrophilic hydroxyl groups, which easily react with moisture or humidity in the air, leading to framework collapse and loss of pores, thus rapidly losing its adsorption and separation properties in humid environments (ACS Appl. Mater. Interfaces, 11 (2018) 2543-2550, AIChE J. 68 (2018) 178772).

[0004] Furthermore, existing CD-MOF materials are mostly in powder form, making them difficult to use directly in industrial adsorption columns. Powdered materials are prone to dust generation, uneven packing, and large pressure drops, and are susceptible to breakage under gas scouring or pressure cycling, resulting in adsorbent loss and equipment blockage. Although some studies have attempted to improve their formability and stability by adding binders, polymer coating, or compression molding, these methods typically reduce the specific surface area and pore accessibility of the material, and may even destroy the ordered structure of the MOF, leading to a significant decrease in adsorption performance.

[0005] Therefore, developing a bulk CD-MOF material that can maintain the intrinsic adsorption properties of CD-MOF while significantly improving its moisture resistance and structural stability has become an urgent need. This invention provides a moisture-resistant and stable bulk cyclodextrin-based metal-organic framework material and its preparation method. A dense bulk structure is obtained by achieving secondary self-assembly growth of CD-MOF particles under mild conditions, and an amorphous carbon coating is generated on the surface through heat treatment under an inert atmosphere. This carbon layer can effectively block the intrusion of water molecules while maintaining the crystallinity and adsorption activity of the framework, enabling the material to operate stably in high-humidity environments. This provides a feasible and scalable solution for the efficient separation of CO2 from hydrocarbon mixtures. Summary of the Invention

[0006] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a moisture-resistant and stable bulk cyclodextrin-based metal-organic framework material and its applications. This material undergoes low-temperature thermal modification to form a thin amorphous carbon coating on its surface, thereby significantly improving its stability in humid and impurity-containing gas environments while maintaining high carbon dioxide adsorption and selectivity. It also offers advantages in operability and large-scale preparation. Furthermore, this invention provides an application scheme for this material in the separation of natural gas and hydrocarbon gases.

[0007] (II) Technical Solution To achieve the above objectives, the present invention is implemented through the following technical solution: a moisture-resistant and stable bulk cyclodextrin-based metal-organic framework material, which is formed by growing primary metal-organic framework particles from γ-cyclodextrin and alkali metal ions, and using newly grown MOF particles at room temperature as a linker to connect the primary particles to form a dense MOF bulk structure. The surface is then heat-treated at 200-260℃ in an inert atmosphere to form an amorphous carbon coating, while maintaining the crystallinity and pore structure of the framework.

[0008] Preferably, the alkali metal ion is K. + or Rb + The preferred metal salts used are KOH or RbOH. The metal-organic framework coordinated with KOH is named CD-MOF-1, while the metal-organic framework coordinated with RbOH is named CD-MOF-2.

[0009] Preferably, the overall block structure is obtained by in-situ growth within a tubular or molded structure, and the individual components are in the geometric shape of a column, disc, sheet, or tube.

[0010] Preferably, the preparation method specifically includes the following steps: S1. Dissolve cyclodextrin and alkali metal salt in a mixed solvent, and centrifuge after ultrasonic or stirring treatment to form a homogeneous and clear solution. S2. Inject the product from step S1 into a mold and let it stand at a certain temperature to allow γ-CD and metal ions to grow in situ into a blocky CD-MOF. S3. Heat-treat the obtained block CD-MOF for a certain time to obtain a moisture-resistant and stable CD-MOF-monolith with an amorphous carbon coating on the surface.

[0011] Preferably, the growth temperature in step S2 is 25-45℃, and the standing time is 12-48h.

[0012] Preferably, the heat treatment temperature in step S3 is 220-260℃, the holding time is 0.5-1h, and the heating rate is 2-10℃ / min.

[0013] Preferably, the heat treatment in step S3 is carried out in an inert atmosphere, which is nitrogen or argon.

[0014] This invention also provides a method for gas separation using a moisture-resistant and stable bulk cyclodextrin-based metal-organic framework material, which is used to selectively adsorb and remove CO2 from a gas stream containing CO2 and hydrocarbons at 298 K and 1 bar. The moisture-resistant and stable bulk cyclodextrin-based metal-organic framework material exhibits a dry-state adsorption capacity > 50 cm⁻¹. 3 g -1 It retains ≥80% adsorption capacity even in a humid state (90% RH, 30 days).

[0015] Preferably, the hydrocarbon is one of CH4, C2H2, C2H4 or C2H6 or a mixture thereof.

[0016] Preferably, the "wet state" specifically refers to maintaining a CO2 adsorption capacity of >80% after being stored for 30 days under conditions of 80-90% relative humidity.

[0017] (III) Beneficial Effects This invention provides a moisture-resistant and stable bulk cyclodextrin-based metal-organic framework material and its applications. Compared with the prior art, it has the following advantages: (1) The moisture-resistant and stable blocky cyclodextrin-based metal-organic framework material and its application: The continuous blocky monomer obtained by in-situ growth avoids the problems of powdering and unstable pressure drop caused by powder filling, which is convenient for modular and industrial filling. Heat treatment forms a uniform amorphous carbon thin layer on the surface, which protects the framework from hydrolysis and partial chemical corrosion, and extends the service life of the material under humid and impurity gas conditions.

[0018] (2) The moisture-resistant and stable blocky cyclodextrin-based metal-organic framework material and its application. The method is a binder-free process that does not introduce deactivating components and can retain about 90% of the original pores and adsorption performance (the example of this invention retains about 90% of the CO2 adsorption capacity). The process is simple and can be batch heat-treated in a conventional tube furnace, making it easy to scale up.

[0019] (3) This moisture-resistant and stable blocky cyclodextrin-based metal-organic framework material and its application demonstrate good engineering application prospects, as it maintains high CO2 capture and selectivity even under high humidity conditions in natural gas / hydrocarbon separation. Obviously, based on the above description of this invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions, or alterations can be made without departing from the basic technical concept of this invention.

[0020] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0021] Figure 1 (a) is a scanning electron microscope (SEM) image of Comparative Example 1; (b) is a SEM image of Example 1.

[0022] Figure 2 (a) shows optical photographs of the bulk MOF structure at different temperatures; (b) shows simulations of different pipeline environments, demonstrating that CD-MOF bulk structures can be grown in various types of pipelines.

[0023] Figure 3 (a) is a scanning electron microscope image of Example 1 after 30 days of treatment at 90% relative humidity; (b) are CO2 adsorption isotherms of Example 1 and Comparative Example 2 after being exposed to 90% humidity at 298K for 30 days and 20 days, respectively.

[0024] Figure 4The experimental breakthrough curve is shown for a CO2 / CH4 / C2H2 / C2H4 / C2H6 mixture in a 20 / 20 / 20 / 20 ratio packed in the adsorption tower of Example 1 at 1.0 bar and 298 K. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Please see Figure 1-4 The present invention provides six technical solutions: a moisture-resistant and stable blocky cyclodextrin-based metal-organic framework material and its application, specifically including the following embodiments: Example 1: 648 mg of γ-cyclodextrin and 224 mg of rubidium hydroxide were weighed and dissolved in 20 mL of deionized water. After stirring evenly, 12 mL of methanol was added to form a mother liquor. The mixed solution was treated with ultrasound at 100 W for 5 min to obtain a clear and transparent solution. Subsequently, 32 mL of a methanol solution containing 256 mg of polyethylene glycol (PEG 20000) was added to the system, and the mixture was incubated at room temperature for 1 h. After centrifugation, the mixture was injected into a mold and allowed to stand at room temperature (25 °C) for 24 h to allow γ-cyclodextrin and metal ions to gradually self-assemble into a monolithic CD-MOF structure. The resulting block product was separated by centrifugation, washed four times each with methanol and ethanol, and then vacuum dried at 50 °C for 24 h. The dried sample was placed in a tube furnace and heated to 240 °C at 5 °C / min under nitrogen protection. After holding at this temperature for 1 h, it was naturally cooled to obtain CD-MOF-2-monolith-240N with a uniform amorphous carbon layer on the surface.

[0027] Example 2: 648 mg of γ-cyclodextrin and 224 mg of potassium hydroxide were weighed and dissolved in 20 mL of deionized water. After stirring evenly, 12 mL of methanol was added to form a mother liquor, and the mixture was treated with ultrasound at 100 W for 5 min. 32 mL of a methanol solution containing 256 mg of PEG 20000 was added, and the mixture was incubated at room temperature for 1 h. After centrifugation, the solution was injected into a mold and allowed to stand at 40 ℃ for 12 h to allow the precursors in the system to crystallize and connect to form a dense whole. The resulting product was centrifuged, washed four times each with methanol and ethanol, and then vacuum dried at 50 ℃ for 24 h. The dried sample was heated to 240 ℃ at a rate of 5 ℃ / min under nitrogen protection, held at this temperature for 1 h, and then cooled to room temperature to obtain a well-crystallized and densely structured CD-MOF-1-monolith-240N-40 ℃ sample.

[0028] Example 3: 648 mg of γ-cyclodextrin and 224 mg of potassium hydroxide were dissolved in 20 mL of deionized water. 12 mL of methanol was added and stirred thoroughly to form a mother liquor. After sonication for 5 min, 32 mL of a methanol solution containing 256 mg of PEG 20000 was added and mixed. The mixture was incubated at room temperature for 1 h, centrifuged, and then injected into a mold. The mold was allowed to stand at room temperature for 48 h to prolong the growth time and promote full cross-linking and self-assembly of the crystals. The resulting blocky product was centrifuged, washed four times with methanol and ethanol, and vacuum dried for 24 h. The dried sample was heated to 240 °C at 5 °C / min under a nitrogen atmosphere, held at this temperature for 1 h, and then cooled to obtain CD-MOF-1-monolith-240N-48h with a more uniform surface carbon layer and stronger integrity.

[0029] Example 4: 648 mg of γ-cyclodextrin and 224 mg of rubidium hydroxide were weighed and dissolved in 20 mL of deionized water. After stirring evenly, 12 mL of methanol was added and mixed. After sonication for 5 min, 32 mL of methanol solution containing 256 mg of PEG 6000 was added, using lower molecular weight polyethylene glycol as a molding aid. The mixture was incubated at room temperature for 1 h, centrifuged, and then injected into a mold. A secondary growth reaction was carried out at 25 °C for 24 h. The product was centrifuged, washed four times each with methanol and ethanol, and then vacuum dried at 50 °C for 24 h. The sample was heated to 240 °C at a rate of 5 °C / min under a nitrogen atmosphere and held for 1 h before cooling to obtain CD-MOF-2-monolith-240N-PEG6000 with a compact structure and uniform pores.

[0030] Example 5: 648 mg of γ-cyclodextrin and 224 mg of potassium hydroxide were dissolved in 20 mL of deionized water. 12 mL of methanol was added to form a mother liquor. After sonication for 5 min, 32 mL of a methanol solution containing 256 mg of PEG 20000 was added. The mixture was incubated at room temperature for 1 h, centrifuged, and then poured into a mold. After standing at room temperature for 24 h, a monolithic block crystal was formed. The obtained sample was centrifuged and washed four times with methanol and ethanol, and then vacuum dried at 50 °C for 24 h. The dried sample was heated to 220 °C at a rate of 5 °C / min under a nitrogen atmosphere, held at this temperature for 1 h, and then naturally cooled to obtain CD-MOF-1-monolith-220N with a slightly carbonized surface. The carbon layer formed at this temperature was relatively thin, maintaining a high specific surface area.

[0031] Example 6: 648 mg of γ-cyclodextrin and 224 mg of potassium hydroxide were weighed and added to 20 mL of deionized water. After stirring evenly, 12 mL of methanol was added, and the mixture was sonicated for 5 min to obtain a clear solution. Then, 32 mL of a methanol solution containing 256 mg of PEG 20000 was added and mixed. The mixture was incubated at room temperature for 1 h, centrifuged, and then injected into a mold. The mixture was allowed to stand at 25 °C for 24 h to generate blocky CD-MOF crystals. The obtained product was washed four times each with methanol and ethanol, and then vacuum dried at 50 °C for 24 h. The dried sample was heated to 260 °C at a rate of 5 °C / min under an argon atmosphere and held at that temperature for 0.5 h before cooling to obtain a CD-MOF-monolith-260Ar sample with a thicker surface carbon layer and enhanced hydrophobicity.

[0032] Comparative Example 1: The preparation of CD-MOF-2 powder is as follows: 648 mg of γ-cyclodextrin and 224 mg of rubidium hydroxide were dissolved in 20 ml of water, and 12 ml of methanol was added to form a mother liquor. The turbid mother liquor was sonicated at 100 W for 5 minutes to obtain a clear solution. Subsequently, 32 ml of methanol containing 256 mg of PEG 20000 was added to the reaction solution. After incubating the mixture at room temperature for 1 hour, the resulting product was washed four times each with methanol and ethanol, and then dried under vacuum at 50 °C for 24 h to obtain CD-MOF-2 powder.

[0033] Comparative Example 2: The preparation of bulk CD-MOF-2 is as follows: 648 mg of γ-cyclodextrin and 224 mg of rubidium hydroxide were weighed and dissolved in 20 mL of deionized water. After stirring evenly, 12 mL of methanol was added to form a mother liquor. The mixed solution was sonicated at 100 W for 5 min to obtain a clear and transparent solution. Subsequently, 32 mL of a methanol solution containing 256 mg of polyethylene glycol (PEG 20000) was added to the system, and the mixture was incubated at room temperature for 1 h. After centrifugation, the solution was injected into a mold and allowed to stand at room temperature (25 ℃) for 24 h to allow γ-cyclodextrin and metal ions to gradually self-assemble into a monolithic CD-MOF structure. The resulting block product was centrifuged, washed four times each with methanol and ethanol, and then dried under vacuum at 50 ℃ for 24 h to obtain CD-MOF-2-monolith.

[0034] Experimental Example 1: Nanoparticle size and microstructure of the bulk cyclodextrin-based metal-organic framework of the present invention 1. Test Methods The samples from Example 1 and Comparative Example 1 were sputter-coated with gold and their microstructures were observed under a scanning electron microscope to confirm the morphology of MOF powder and some carbonized bulk MOF.

[0035] 2. Test Results like Figure 1 As shown in Figure a, the CD-MOF-2 powder in Comparative Example 1 consists of primary particles of approximately 300 nanometers in size, while the surface of the CD-MOF-2 bulk structure in Example 1 exhibits a relatively flat state. Figure 1 (b) The particles are tightly packed and interconnected. Larger metal-organic framework particles are composed of numerous smaller particles, forming a dense structure with no visible voids. This compactness is attributed to the secondary growth of crystals on primary particles, the presence of residual precursors, and the slow evaporation of the solvent at room temperature. High-magnification scanning electron microscope image ( Figure 1 (Image b) shows that the surface of the cubic crystal is covered with a layer of amorphous carbon coating.

[0036] Experimental Example 2: Effect of carbonization temperature on the bulk cyclodextrin-based metal-organic framework of the present invention and its pipeline adaptability 1. Test Methods The morphology of the blocky cyclodextrin-based metal-organic framework samples of Comparative Example 1 and those treated at different temperatures was photographed. The mold used for sample growth in Example 1 was replaced with various simulated pipes.

[0037] 2. Test Results like Figure 2 As shown in Figure a, the heat treatment temperature was controlled within the range of 220–280℃. Below 260℃, the blocky structure of CD-MOF-2 remained intact; however, when the temperature rose to 260℃, the overall structure collapsed. Figure 2 As shown in b, CD-MOF-2 monolithic crystals are grown directly in pipes of different shapes. The crystals can be grown in pipes of different shapes and are attached to the inner wall of the pipes in a monolithic form without falling off.

[0038] Experimental Example 3: Gas separation performance and moisture resistance of the blocky cyclodextrin-based metal-organic framework of the present invention 1. Test Methods In the moisture resistance test, the samples were first placed at 90% relative humidity for 30 days. Before the test, all samples were placed in an environment with 90% relative humidity (RH) and then activated at 110°C for 12 hours to remove surface adsorbed impurities. Carbon dioxide adsorption measurement and surface morphology test were then performed.

[0039] 2. Test Results like Figure 3 As shown in Figure a, even after being placed in a 90% humidity environment for 30 days, Example 1 still maintained its flat surface and cubic crystal structure. This indicates that the compacted metal-organic framework is insensitive to humidity, thereby improving the applicability of CD-MOF under high humidity conditions. Figure 3b demonstrates the carbon dioxide adsorption capacity of different samples at 90% humidity, providing a quantitative indicator for the moisture resistance after thermal modification. Comparative Example 2, after 20 days of exposure to high humidity, showed a decrease in carbon dioxide adsorption from 68.2 cm⁻¹. 3 g -1 Reduced to 15.7 cm 3 g -1 The retention rate was only 23%. In contrast, under the same conditions, Example 1 showed a significantly higher carbon dioxide adsorption retention rate (90%) after 30 days, indicating enhanced stability in humid environments.

[0040] Experimental Example 4: Mixed Gas Separation Performance of the Blocky Cyclodextrin-Based Metal-Organic Framework of the Present Invention 1. Test Methods To investigate the performance of bulk cyclodextrin-based metal-organic frameworks in separating gas mixtures under dynamic conditions, a breakthrough experiment was conducted at 298 K and 100 kPa. Before the experiment, approximately 1.00 g of the sample from Example 1 was packed into a breakthrough column (6 mm × 100 mm) and activated under vacuum at 80 °C for 12 hours. To remove impurities from the apparatus, 20 mL of the sample was injected at a constant temperature. −1 The column packed with activated sample was continuously purged with helium for 2 hours. After purging, the column was allowed to cool naturally to room temperature, and then flowed at 12 mL / min. −1 The flow rate injects the mixed gas into the breakthrough column.

[0041] 2. Test Results like Figure 4 As shown, Example 1 effectively captured carbon dioxide from a mixture of CO2 / CH4 / C2H2 / C2H4 / C2H6 (ratio 20 / 20 / 20 / 20 / 20) under conditions of 298 K and 100 kPa. Rapid breakthrough phenomena were observed in this experiment for CH4, C2H2, C2H4, and C2H6, with their elution peaks appearing earlier and sharper, while CO2 was not detected until 30 minutes later. This indicates that the presence of multiple components did not weaken the CO2 capture ability of Example 1.

[0042] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0043] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A moisture-stable, bulk, cyclodextrin-based metal-organic framework material, characterized by: The material is formed by growing γ-cyclodextrin with alkali metal ions into metal organic framework primary particles, the new MOF particles grown at room temperature slowly serve as a linker to connect the primary particles to each other, thereby forming a compact MOF monolith structure, and the surface amorphous carbon coating is formed by heat treatment at 200-260℃ under inert atmosphere, while maintaining the framework crystallinity and pore structure.

2. The moisture-stable bulk CD-MOFs according to claim 1, and uses thereof, characterized in that: The alkali metal ion is K + or Rb + .

3. The moisture-stable bulk CD-MOF material of any one of claims 1-2, wherein: The monolith structure is grown in situ in a tubular or mold, and the monomer is in the form of a column, disc, sheet or tube geometry.

4. The moisture-stable bulk CD-MOF material of claim 1, wherein: The preparation method specifically comprises the following steps: S1, dissolving cyclodextrin and alkali metal salt in a mixed solvent, forming a uniform clear solution by ultrasonic or stirring treatment, and then centrifuging; S2, injecting the product of step S1 into a mold and standing at a certain temperature, so that γ-CD grows in situ with metal ions into a monolithic CD-MOF; S3, heat treating the obtained monolithic CD-MOF for a certain time to obtain a moisture-resistant stable CD-MOF-monolith with a surface amorphous carbon coating.

5. The moisture-stable bulk CD-MOF material of claim 4, wherein: The growth temperature of step S2 is 25-45℃, and the standing time is 12-48h.

6. The moisture-stable bulk CD-MOF material of claim 4, wherein: The heat treatment temperature of step S3 is 220-260℃, the holding time is 0.5-1h, and the heating rate is 2-10℃ / min.

7. The moisture-stable bulk CD-MOF material of claim 4, wherein, The heat treatment in step S3 is carried out in an inert atmosphere, and the atmosphere is nitrogen or argon.

8. A method for gas separation using the moisture-stable bulk metal-organic framework material of claim 4, characterized in that: A bulk cyclodextrin-based metal-organic framework material for selective adsorption and removal of CO2 from a gas stream containing CO2 and hydrocarbons at 298 K, 1 bar conditions, and stable to moisture, with a dry state adsorption capacity > 50 cm 3 g -1 and retaining > 80% adsorption capacity in the wet state.

9. Use of a moisture-stable bulk metal-organic framework material of cyclodextrin for gas separation according to claim 8, characterized in that, The hydrocarbon is one of CH4, C2H2, C2H4 or C2H6 or a mixture thereof.

10. Use of a moisture-stable bulk metal-organic framework material of cyclodextrin for gas separation according to claim 8, characterized in that: The wet state is specifically that the CO2 adsorption capacity remains >80% after being stored under 80-90% relative humidity for 30 days.

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