Three-dimensional (3D) hydrophobic high-amine metal-organic structures with high selectivity for capturing wet CO2

Abstract

This disclosure relates to metal-organic frameworks (MOFs). Specifically, this disclosure relates to a copper(I)-melamine-based three-dimensional hydrophobic MOF with high CO2 selectivity from a humid atmosphere, and a method for synthesizing the same. Furthermore, this disclosure relates to a method for capturing CO2 from a humid atmosphere using the 3D hydrophobic MOF.

Description

Technical Field

[0001] The present disclosure relates to metal-organic frameworks (MOFs). Specifically, the present disclosure relates to three-dimensional (3D) hydrophobic high-amine melamine-based MOFs with high CO2 selectivity from a humid atmosphere, and methods for synthesizing the same. Furthermore, the present disclosure relates to a method for capturing CO2 from a humid atmosphere using the 3D hydrophobic MOF.

Background Art

[0002] The background description includes information that may be useful in understanding the present disclosure. None of the information presented in this specification is admitted to be prior art, or related to the presently claimed invention, or that any of the publications specifically or implicitly referenced is prior art. Carbon dioxide (CO2) is a greenhouse gas and is often the target of removal from natural gas and other industrial gas streams. Conventional methods for removing carbon dioxide are often expensive and multi-stage processes because such gas streams must first be dehydrated before CO2 can be captured. The reason is that water vapor strongly interacts with porous materials that physically sorb CO2. Metal-organic frameworks have already been identified as potential candidates for separating CO2 from gas mixtures such as CO2 / N2, CO2 / H2, CO2 / CH4, CH4 / N2, etc. Hundreds of MOFs with a CO2 uptake capacity of >3 mmol / g and a selectivity of >100 have been reported. Importantly, MOFs with amine functional groups are suitable for the selective capture of CO2. However, due to the four main requirements: (1) water / vapor stability, (2) selective capture of CO2 from a humid gas stream, and (3) chemical stability, and (4) cost-effectiveness, they do not reach the level of applicability. As far as we know, no single MOF with the above capacity and selectivity meets all these other material requirements. Unless these are met, it is impossible to replace competitive adsorbents such as zeolites and carbon used in industrial CO2 capture with MOFs. Therefore, there is an urgent need to design a MOF that is superhydrophobic and also has excellent CO2 capture capabilities from a humid atmosphere. This disclosure satisfies existing and other needs and generally overcomes the shortcomings found in the prior art. [Overview of the Initiative] [Problems that the invention aims to solve]

[0003] The purpose of this disclosure is to provide a superhydrophobic MOF that is further functionalized for excellent CO2 scavenging ability from a humid atmosphere. The purpose of this disclosure is to provide a 3D hydrophobic high-amine MOF with high CO2 selectivity from a humid atmosphere. Another object of this disclosure is to provide a method for synthesizing 3D hydrophobic high-amine MOFs with high CO2 selectivity from a humid atmosphere. Another object of this disclosure is to provide a method for capturing CO2 from a humid atmosphere using the 3D hydrophobic MOF. [Means for solving the problem]

[0004] This summary is provided to briefly introduce various concepts that will be further described in the following detailed explanations. This summary is not intended to identify any essential or important features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. This disclosure relates to metal-organic frameworks (MOFs). Specifically, this disclosure relates to three-dimensional (3D) hydrophobic high-amine MOFs with high CO2 selectivity from a humid atmosphere, and to a method for synthesizing the same. Furthermore, this disclosure relates to a method for capturing CO2 from a humid atmosphere using the 3D hydrophobic MOF. In one embodiment, the present disclosure relates to a 3D hydrophobic MOF that can be characterized by the formula MN(ORG)(OH).(SOLVENT)x, where MN is the metal node Cu(I); ORG is the organic ligand melamine; x is from 0 to 10; and SOLVENT is one or more DMFs. In a preferred embodiment, the present disclosure relates to a 3D hydrophobic MOF that can be characterized by the formula Cu(C3N3H6)(OH).(DMF / H2O)x, where x is from 0 to 10. In a preferred embodiment, the disclosure relates to a 3D hydrophobic MOF having an optimal concentration of charge-balanced hydroxide ions in its pores, such that the CO2 / N2 selectivity is about 300 and CO2 uptake at RT is reliably >3 mmol / g, and the same state is maintained throughout the entire load (from zero to >3 mmol of CO2). In another embodiment, the present disclosure relates to a method for synthesizing 3D hydrophobic MOFs, the method being The process involves inducing a solvothermal reaction between a metal skeleton source, an organic ligand skeleton source, and terephthalic acid in an organic solvent, followed by cooling to room temperature to obtain the reaction product; The reaction product is filtered to obtain block-type pale green crystals of the 3D hydrophobic MOF; The process involves ultrasonically decomposing block-type pale green crystals in an organic solvent, followed by filtration to remove unreacted terephthalic acid; The process includes washing with a large amount of alkanol to obtain a 3D hydrophobic MOF. In yet another embodiment, the present disclosure relates to a method for sorbing CO2 from a humid atmosphere, wherein the method is a. A step of contacting the MOF disclosed herein with a fluid or gas stream containing H2O, CO2, CH4, N2, H2, etc., so that CO2 is adsorbed onto the MOF; b. A step of optionally regenerating the MOF for the next CO2 sorption cycle, including

[0005] Various purposes, features, aspects, and advantages of the subject matter of the invention will become apparent from the following detailed description of preferred embodiments.

[0006] The following drawings form part of this specification and are included to further illustrate aspects of this disclosure. This disclosure can be better understood by combining the detailed description of the specific embodiments shown herein with reference to the drawings. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows the structure revealed by single-crystal X-ray diffraction. (A) Three-coordinate structure around a Cu(I) center formed by three melamine moieties. (B) A uniform one-dimensional channel in IISERP-MOF22(1) where the amine groups of melamine are aligned. Free hydroxyl groups in the channel are not shown for clarity. (C) Structure of the MOF showing the shape along the a-axis. Hydroxide ions aligned in the channel are shown in red. Color codes: Zn-cyan; C-gray; N-blue; O-red; H-white. [Figure 2] Figure 2 compares the powder X-ray diffraction pattern simulated from single-crystal data with that obtained experimentally, indicating the phase purity. [Figure 3] Figure 3 shows the TGA performed on a 3D hydrophobic MOF. [Figure 4] Figure 4 shows the adsorption isotherms performed on a 3D hydrophobic MOF. [Figure 5] Figure 5 shows the pore width of a 3D hydrophobic MOF estimated by NLDFT suitable for the adsorption branch of the 273k CO2 isotherm. [Figure 6] Figure 6 shows the calculated IAST selectivity for different gas mixtures for 3D hydrophobic MOFs. [Figure 7] Figure 7 shows the heat of adsorption calculated for 3D hydrophobic MOFs using two different methods. [Figure 8] Figure 8 shows the CO2 cycle of volumetric measurements performed on a 3D hydrophobic MOF, demonstrating the recyclability of the MOF. [Figure 9] Figure 9 shows the CO2 cycle of gravimetric measurements performed on a 3D hydrophobic MOF, demonstrating the recyclability of the MOF. [Figure 10] Figure 10 shows the CO2 / N2 breakthrough performed on a 3D hydrophobic MOF with a total flow rate of 25 ml / min (20 ml CO2 + 5 ml N2). [Figure 11] Figure 11 shows the CO2 / N2 breakthrough cycle, which does not show loss in the retention time after multiple cycles. [Figure 12] Figure 12 shows the water sorption isotherms of a 3D hydrophobic MOF, indicating that the interaction between the MOF and water molecules is minimal. [Figure 13] Figure 13 shows the PXRD of 3D hydrophobic MOFs treated under different conditions, demonstrating the exceptionally good stability of the MOFs. [Modes for carrying out the invention]

[0008] The following is a detailed description of embodiments relating to this disclosure. These embodiments are very detailed and clearly illustrate this disclosure. However, the gist of the details shown is not intended to limit the expected variations of the embodiments, and rather the present invention encompasses all modifications, equivalents and substitutions that fall within the spirit and scope of this disclosure. All publications herein are incorporated by reference to the same extent that individual publications or patent applications are specifically and individually incorporated by reference. If a definition or use of a term in an incorporated reference conflicts with or contradicts a definition of that term provided herein, the definition provided herein shall apply, and the definition in the reference shall not apply. Throughout this specification, any reference to “one embodiment” or “a certain embodiment” means that the specific features, structures, or characteristics described in relation to this embodiment are included in at least one embodiment. Therefore, the appearance of the phrase “in one embodiment” or “in a certain embodiment” in various places in this specification does not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics can be suitably combined in one or more embodiments. In some embodiments, for the purposes of describing and claiming particular embodiments of the present invention, numbers are used to quantify properties such as mass percentages, ratios, and the like. In some instances, they are to be understood as being modified by the term "about". Accordingly, in some embodiments, the numerical parameters set forth in the specification and attached claims are approximations and may vary depending upon the desired properties sought in specific embodiments. In some embodiments, the numerical parameters should be construed in light of the reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters representing the broad scope of some embodiments of the present invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the present invention may contain certain errors necessarily resulting from the standard deviation found in the respective test measurements.

[0009] The various terms used herein are defined below. Unless otherwise defined in the claims, the terms used in the claims should be given to those skilled in the art the broadest definition reflected in published applications and issued patents as of the filing date. As used throughout this specification and the claims below, the meaning of "a", "an", and "the" includes plural referents unless the context clearly dictates otherwise. Also, as used herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise. Unless the context dictates otherwise, throughout the following specification, the word "comprise", and variations such as "comprises" and "comprising" are to be construed in an open, inclusive sense, i.e., as "including, but not limited to".

[0010] The description of a range of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Each separate value is incorporated into the specification as if it were individually recited herein unless otherwise indicated herein. All methods described herein may be performed in any preferred order, unless otherwise indicated herein or unless it is clearly inconsistent with the context. Any and all examples or exemplary words (e.g., "etc.") shown in reference to specific embodiments herein are intended solely to further illustrate the invention and not to limit the scope of the invention as otherwise claimed. Words herein should not be construed as referring to any unclaimed elements essential to the practice of the invention. The grouping of alternative elements or embodiments of the present invention disclosed herein should not be construed as limiting. Each component of a group may be referenced and claimed individually, or may be referenced and claimed in any combination with other components of that group or other elements found herein. One or more components of a group may be included in or removed from a group for convenience and / or patentability reasons. Any such inclusion or removal shall be deemed to include the modified group.

[0011] The following description and embodiments described herein are provided to illustrate one or more examples of specific embodiments relating to the principles and aspects of the disclosure. These examples are provided for illustrative purposes only and do not limit the principles or the disclosure. It should also be understood that this disclosure can be implemented in numerous ways, including systems, methods, or apparatus. In this specification, these implementations, or any other forms that the invention may take, may be referred to as processes. Generally, the order of steps in the disclosed processes may be modified within the scope of the invention. The items and abstract of the invention described herein are provided for convenience only and do not describe the scope or meaning of the embodiments. The following discussion provides numerous exemplary embodiments relating to the subject matter of the present invention. Each embodiment represents a single combination of the inventive elements, but the subject matter of the invention is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment includes elements a, b, and c, and a second embodiment includes elements b and d, then the subject matter of the invention is considered to include other remaining combinations of a, b, c, or d, even if not explicitly disclosed. As used herein, the term “humid atmosphere” refers to one or more gases, liquids, or combinations thereof. A gas or liquid may contain one or more components. Examples of humid atmospheres include gas streams containing H2O, CO2, CH4, N2, H2, etc. As used herein, the terms “capture” or “capture” refer to the action of removing one or more chemical species from a large volume of fluid composition (e.g., gas / vapor, liquid and / or solid). For example, “capture” can include, but are not limited to, chemical, electronic, electrostatic, physical or dynamic interactions, bonding, diffusion, adsorption, absorption, reaction, and sieving. When used herein, "carbon dioxide" and / or "CO2" may include solid, liquid, and / or gaseous / vapor phases.

[0012] This disclosure relates to metal-organic frameworks (MOFs). Specifically, this disclosure relates to a three-dimensional (3D) hydrophobic MOF with high CO2 selectivity from a humid atmosphere, and a method for synthesizing the same. Furthermore, this disclosure relates to a method for capturing CO2 from a humid atmosphere using the 3D hydrophobic MOF. A MOF (Metabolic Object Frame) consists of a network of nodes and ligands, where each node has the ability to bind to three or more functional sites, and each ligand has the ability to bind to two functional sites, each of which is linked to a node. Nodes are typically metal ions or metal-containing clusters, while ligands are organic ligands. The specific combination of metal nodes and organic ligands within the structure determines the structure's topology and functionality. In some embodiments of this disclosure, a 3D hydrophobic MOF may be characterized by the formula MN(ORG)(OH).(SOLVENT)x, where MN is a metal node; ORG is an organic ligand (also known as an organic structure); x is between 0 and 10; and SOLVENT is an organic solvent. In some embodiments of this disclosure, the metal node (also known as a metal structure) is preferably a metal salt such as a nitrate, chloride, sulfate, acetate, hydroxide, oxide, acetylacetonate, bromide, carbonate, carboxylate, tartrate, or perchlorate. Preferably, it is a metal nitrate, and more preferably, copper nitrate. In some embodiments of this disclosure, SOLVENT is an organic solvent, selected from, but not limited to, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-diethylformamide (DEF), N,N-dimethylacetamide (DMAc), acetonitrile, toluene, dioxane, benzene, chlorobenzene, methyl ethyl ketone (MEK), pyridine, tetrahydrofuran (THF), ethyl acetate, and the like. Most preferably, DMF is used. In some embodiments of this disclosure, 3D hydrophobic MOFs can exhibit one or more high removal efficiencies and / or high uptake efficiencies even at low concentrations of CO2. For example, 3D hydrophobic MOFs can exhibit removal efficiencies of over 50%, over 75%, and over 90%. In many embodiments, 3D hydrophobic MOFs exhibit removal efficiencies of over 90%. For example, 3D hydrophobic MOFs can exhibit removal efficiencies of at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, and / or at least 99.9%. In one embodiment of this disclosure, the 3D hydrophobic MOF lacks any ferropolar oxygen in its structure, and this material has very little affinity for water as manifested by TGA and water sorption.

[0013] In another embodiment, the present disclosure provides a method for synthesizing 3D hydrophobic MOFs, the method being described as follows: The process involves inducing a solvothermal reaction between a metal structure source, an organic ligand structure source, and terephthalic acid in an organic solvent, followed by cooling to room temperature to obtain the reaction product; The reaction product is filtered to obtain block-type pale green crystals of the 3D hydrophobic MOF; The process involves ultrasonically decomposing block-type pale green crystals in an organic solvent, followed by filtration to remove unreacted terephthalic acid; The process includes a step of washing with a large amount of alkanol to obtain a 3D hydrophobic MOF. In some embodiments of this disclosure, the metal structure source is not limited, but copper nitrate trihydrate is selected. In some embodiments of this disclosure, the source of the organic ligand structure is not limited, but melamine is selected. In some embodiments of this disclosure, the ratio of the metal ion source to the ligand source is about 0.1:1 to 1:0.1, respectively. The most preferred ratio is 1:1. In some embodiments of this disclosure, the organic solvent is selected from DMF, EtOH, NMP, and MeOH. Most preferably, it is DMF. In some embodiments of this disclosure, the alkanol is selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, pentanol, hexanol, and mixtures thereof. Most preferably, methanol is used. In one embodiment of this disclosure, the 3D hydrophobic MOF is given by the formula MN(ORG)(OH).(SOLVENT). x The formula can be characterized as follows, where MN is the metal node Cu(I); ORG is the organic ligand melamine; x is between 0 and 10; and SOLVENT is one or more DMFs.

[0014] In another embodiment, the present disclosure provides a method for synthesizing 3D hydrophobic MOFs, the method being described as follows: The process involves inducing a solvothermal reaction between copper nitrate trihydrate, melamine, and terephthalic acid in DMF, followed by cooling to room temperature to obtain the reaction product; The reaction product is filtered to obtain block-type pale green crystals of the 3D hydrophobic MOF; The process involves ultrasonically decomposing block-type pale green crystals in an organic solvent, followed by filtration to remove unreacted terephthalic acid; The process includes a step of washing with a large amount of methanol to obtain a 3D hydrophobic MOF. MOFs cannot be formed without terephthalic acid, and furthermore, Cu2+ is reduced to metallic copper, Cu(0). Terephthalic acid can be substituted with oxalic acid, and the same CuMOF can be obtained, but in a relatively low yield. Terephthalic acid / oxalic acid seems to be extremely important to ensure that Cu2+ is not reduced to Cu(0). Importantly, these dicarboxylic acids do not form any competing phases under these reaction conditions and simply act as redox control. In some embodiments of this disclosure, the ratio of copper nitrate trihydrate to melamine is about 0.1:1 to 1:0.1, respectively. The most preferred ratio is 1:1. In one embodiment of this disclosure, the concentration of copper nitrate trihydrate is approximately 0.1 mmol to 1 mmol. For example, 0.1 mmol, 0.2 mmol, 0.3 mmol, 0.4 mmol, 0.5 mmol, 0.6 mmol, 0.7 mmol, 0.8 mmol, 0.9 mmol, or 1.0 mmol. In one embodiment of this disclosure, the concentration of melamine is approximately 0.1 mmol to 1 mmol. For example, 0.1 mmol, 0.2 mmol, 0.3 mmol, 0.4 mmol, 0.5 mmol, 0.6 mmol, 0.7 mmol, 0.8 mmol, 0.9 mmol, or 1.0 mmol. In one embodiment of this disclosure, the concentration of terephthalic acid is approximately 0.1 mmol to 1 mmol. For example, 0.1 mmol, 0.2 mmol, 0.3 mmol, 0.4 mmol, 0.5 mmol, 0.6 mmol, 0.7 mmol, 0.8 mmol, 0.9 mmol, or 1.0 mmol. In some embodiments of this disclosure, the solvothermal reaction is carried out at 90°C to 150°C, more preferably 120°C. In some embodiments of this disclosure, the solvothermal reaction is carried out for 48 to 96 hours, more preferably 72 hours. In preferred embodiments of this disclosure, the 3D hydrophobic MOF is given by the formula Cu(C3N3H6)(OH).(DMF) x (H2O) y It can be characterized as follows, where x is from 0 to 0.5 and y is from 0 to 0.2. In some embodiments of this disclosure, the yield of the 3D hydrophobic MOF is about 50%, about 60%, and about 70% or more. In many embodiments, the yield is about 65%. For example, at least 65%, at least 66%, at least 67%, at least 68%, at least 69%, at least 70%, at least 72%, at least 73%, at least 74%, and / or at least 75%.

[0015] In yet another embodiment, the present disclosure provides a method for sorbing CO2 from a humid atmosphere, the method being c. A step of contacting the MOF disclosed herein with a fluid or gas stream containing H2O, CO2, CH4, N2, H2, etc., so that CO2 is adsorbed onto the MOF; d. A step of optionally regenerating the MOF for the next CO2 adsorption cycle. In one embodiment of the present disclosure, CO2 capture includes the step of bringing a 3D hydrophobic MOF into contact with a fluid or gas stream containing H2O, CO2, CH4, N2, H2, etc. In one embodiment, the contact may include physical contact, close contact, or proximity between the metal-organic structure and the fluid composition. Examples of contact include, but are not limited to, supplying, flowing, passing, pumping, and introducing. In some embodiments of this disclosure, CO2 capture further comprises an optional step of regenerating a 3D hydrophobic MOF. Regeneration may include heat treatment in a vacuum and / or inert gas environment (e.g., under nitrogen). In some embodiments of this disclosure, contact can be carried out under any preferred conditions (e.g., temperature, pressure, etc.). For example, contact can be carried out at or at temperatures from about 25°C to about 200°C. In many embodiments, contact can be carried out at or up to temperatures below about 200°C. In preferred embodiments, contact can be carried out at or up to temperatures of about 25 to 35°C (e.g., about room temperature). In some embodiments of this disclosure, the CO2 concentration in the gas flow may be about 0% to about 99.9%. In many embodiments, the CO2 concentration in the fluid composition is less than about 10%. In preferred embodiments, the CO2 concentration in the fluid composition is in the range of about 3% to about 50%. The material is also stable in a 100% CO2 flow. In one embodiment of the present disclosure, the 3D hydrophobic MOF has channels with amines lined in the pores and an optimal concentration of charge-balanced hydroxide ions such that the CO2 / N2 selectivity is about 300 and CO2 uptake at RT is reliably >3 mmol / g. In some embodiments of this disclosure, the 3D hydrophobic MOF has water / vapor stability, chemical stability, and is more economical. In one embodiment of this disclosure, the MOF is synthesized in large quantities as a pure phase, as can be seen from PXRD, the MOF retains all functional groups, as can be clearly seen from the IR spectrum, and the MOF is stable up to 280°C, as can be clearly seen from TGA. Post-treatment PXRD confirms that the MOF is stable to water treatment and even boiling in water, and is stable in various solvents including DMF, THF, methanol, ethanol, and toluene. The MOF is stable in vapor and water, and the MOF exposed to flue gas (produced from burning coal) retains its crystallinity and porosity.

[0016] While the above description discloses various embodiments of the present disclosure, other and further embodiments of the present invention can be devised without departing from the basic scope of the present disclosure. The present invention is not limited to the embodiments, variations, or examples described herein, which are included to enable those skilled in the art to practice and use the present invention by combining information and knowledge available to those skilled in the art. [Examples]

[0017] The present disclosure will be further illustrated in the form of the following embodiments. However, the above-mentioned examples are for illustrative purposes only and should not be construed as limiting the scope of the invention. Various changes and modifications to the disclosed embodiments will be obvious to those skilled in the art. Such changes and modifications can be made without departing from the scope of the invention. Example 1: Synthesis of 3D hydrophobic MOF A solvothermal reaction was carried out in 5 ml of DMF between copper nitrate trihydrate (0.1 mmol), melamine (0.1 mmol), and terephthalic acid (0.1 mmol) at 120°C for 72 hours. After cooling to room temperature, block-type pale green crystals were obtained by filtration. The yield of isolation was approximately 70%. The product was sonicated in DMF and filtered again to wash away all unreacted terephthalic acid. Finally, it was washed with a large amount of methanol to obtain a 3D hydrophobic MOF.

[0018] Example 2: Characterization of the 3D hydrophobic MOF from Example 1 The bulk phase purity was determined by powder X-ray diffraction, and the structure was elucidated from single-crystal X-ray diffraction. Other standard characterizations such as thermal analysis, IR spectral analysis, and porosity measurements were also performed. The sample is of very high purity. Importantly, the oxidation state of copper in the MOF is proven to be +1 by XPS analysis. In the prepared sample, the solvent is mainly DMF, with some adsorbed water molecules. When activated by heating under vacuum, the solvent is almost nonexistent. The hydrophobicity of the activated sample is well demonstrated by contact angle measurements and water adsorption isotherms. The material exhibits excellent thermal and chemical stability.

[0019] Single-crystal X-ray diffraction: Single-crystal data were acquired using a Bruker SMART APEX 4-axis diffractometer equipped with a CMOS-mounted photon100 detector (Bruker Systems Inc.) and MoKα (0.71 Å). The incident X-ray beam was focused and monochromatized using a microfocus (I μS). Crystal 1 was mounted in a paraton-N oil and nylon cryoloop. Data were acquired at 100(2) K. Data were integrated using Bruker's SAINT software and corrected for absorption using SADABS. The structure was elucidated using a direct intrinsic phase determination module and refined using the SHELXTL2014 software suite. All non-hydrogen atoms were located by repeated testing of different F maps, and the structure was then refined using the least squares method. Hydrogen atoms were geometrically arranged using a riding model. Crystal parameters: X-ray source: Mo-Kα; Crystal system: P6522; Unit cell parameters: a=10.3578(3); b=10.3578(3); c=14.5744(5); α=90; β=90; γ=120; R1=4.4%; wR2=12.1%; GOF=1.05. The structure elucidated from single-crystal X-ray diffraction is as follows: (A) Three-coordinate structure around a Cu(I) center formed by three melamine moieties. (B) A uniform one-dimensional channel in IISERP-MOF22(1) where the amine groups of melamine are aligned. Free hydroxyl groups in the channel are not shown for clarity. (C) Structure of the MOF showing the shape along the a-axis. Hydroxide ions aligned in the channel are shown in red. Color codes: Zn-cyan; C-gray; N-blue; O-red; H-white (Figure 1). Powder X-ray diffraction pattern: The newly prepared samples were washed with methanol and dried overnight in an oven at 80°C. The powder X-ray diffraction patterns were then measured using Cu-Kα radiation with a Rigaku powder X-ray diffraction system. Figure 2 shows the analysis results.

[0020] TGA analysis: Freshly prepared samples were filtered and dried overnight in the air before performing TGA analysis. For methanol-immersed samples, the prepared samples were immersed in methanol for 3 days, filtered, and dried overnight. All TGA analyses were performed under a nitrogen stream (20 ml / min). TGA performed on the fabricated MOF showed a 2.5% mass loss at 90°C, which is attributed to solvent molecules present on the surface. In the sample immersed in MeOH, the initial mass loss was due to methanol present on the surface. Subsequently, there was no further mass loss, indicating that there are no solvent molecules inside the pores. The material is thermally stable up to 280°C (Figure 3). Adsorption isotherm: Prior to adsorption, the methanol-immersed sample was activated by heating under vacuum at 130°C for 24 hours. All gases were of at least 99.999 purity grade. Isotherms were measured using a Micromeritix ASAP2020 instrument. Sample volume used = approximately 150 mg. The adsorption isotherms (Figure 4) obtained on the 3D hydrophobic MOF show a type I isotherm for CO2 and linear isotherms for N2, H2, and CH4. Adsorption-desorption isotherms of pure components (0 to 1 bar) confirm CO2 uptake (approximately 4 mmol / g at 298K). Other gases do not adsorb under the same conditions, even in any evaluable amount. The MOF can be regenerated by he sweeping alone, by discharge under a moderate vacuum, or by vacuum + heating (80°C). Pore ​​width In a separate independent experiment, Cu-MOFs were treated with a (purchased) industrial flue gas composition for over 24 hours, and their crystallinity and porosity remained unchanged. Figure 5 shows the pore width of the 3D hydrophobic MOF, estimated by NLDFT suitable for the adsorption branch of the 273K CO2 isotherm.

[0021] IAST selectivity: Figure 6 shows the IAST selectivity of 3D hydrophobic MOFs calculated for different gas mixtures. When calculated using the IAST method, for example, the selectivity of CO2 compared to N2 is 300 for an 85%N2+15%CO2 composition. Heat of adsorption: The heat of adsorption for 3D hydrophobic MOFs was calculated using two different methods. A moderate HOA of 25 kJ / mol can be very useful for easily regenerating MOFs (Figure 7). Recyclability of MOFs: An activated sample (approximately 150 mg) was used to perform a continuous adsorption-desorption cycle, and this sample was activated by vacuum only (no heating) after each cycle. The CO2 cycle of volumetric measurements performed on the 3D hydrophobic MOF demonstrates the recyclability of the MOF (Figure 8). The CO2 adsorption cycle has been demonstrated by equilibrium adsorption for volumetric analysis of pure components, isocycle for volumetric analysis, and gravimetric analysis in a TGA instrument. In the volumetric analysis cycle, the sample was saturated with CO2 and then discharged before the next cycle, and this cycle was performed five times without loss of volume. For the gravimetric analysis cycle, the sample was dozed with CO2 until saturated, and then the adsorbed CO2 was completely removed by a He sweep. This cycle was repeated 12 times without loss of CO2 volume. All of these cycles and equilibrium adsorption for volumetric analysis (in a porosity analyzer) were performed at room temperature. A gravimetric cycle experiment was performed by loading 20 mg of activated sample into a thermogravimetric analyzer, and several adsorption-desorption cycles were carried out. In this experiment, the flow of CO2 (20 ml / min) and N2 (20 ml / min) was switched at regular intervals. CO2 adsorption occurred in the CO2 flow, and then the N2 flow was used to wash away all the adsorbed CO2. The CO2 cycle of gravimetric analysis performed on a 3D hydrophobic MOF demonstrates the recyclability of the MOF (Figure 9).

[0022] CO2 / N2 breakthrough: In another experiment, a breakthrough analyzer was used to demonstrate the ability of an MOF to separate CO2 from a CO2 / N2-containing mixture. A column containing the MOF was treated with the mixture. Selective adsorption and recovery of CO2 were observed (during the breakthrough run, approximately 3.3 mmol / g of CO2 was separated from the 85%N2+15%CO2 mixture under dry conditions and 3.5 mmol / g under humid conditions (humidity >75%)). The amount of CO2 separated by this method was consistent across multiple runs. CO2 / N2 breakthrough testing was performed on a 3D hydrophobic MOF at a total flow rate of 25 ml / min (20 ml CO2 + 5 ml N2). The breakthrough retention time was normalized per gram of sample. For detection, measurements were performed using a Rubotherm breakthrough analyzer with a high-resolution mass spectrometer. The results are shown in Figure 10. The CO2 / N2 breakthrough cycle shows no loss in retention time after multiple cycles (Figure 11). Interaction with water: The 298K water sorption isotherm for 3D hydrophobic MOFs indicates minimal interaction between MOFs and water molecules (Figure 12). Measurements were performed using Micromeritix's ASAP2020 instrument. Stability of 3D hydrophobic MOFs: Solutions with a pH in the range of 1 to 14 were prepared, and MOFs were immersed in each solution (50 mg per 20 ml of solution). The MOFs were filtered and subjected to PXRD after 24 hours. PXRD of 3D hydrophobic MOFs treated under different conditions demonstrated the exceptionally superior stability of the MOFs (Figure 13).

Claims

1. CO from a humid atmosphere 2 A highly selectable, reusable three-dimensional hydrophobic, highly amine-porous metal-organic structure (3D hydrophobic MOF) characterized by the formula MN(ORG)(OH).(SOLVENT)x, In the formula, MN is the metal node Cu(I); ORG is the organic ligand melamine; x is from 0 to 10, and SOLVENT is one or more DMFs. A 3D hydrophobic MOF characterized by three-coordinate arrangement around a Cu(I) center due to the melamine portion, and uniform one-dimensional channels in the 3D hydrophobic MOF where the amine groups of the melamine are aligned.

2. Formula Cu(C) 3 N 3 H 6 )(OH). (DMF / H 2 The 3D hydrophobic MOF according to claim 1, characterized by O) x, wherein x is from 0 to 10.

3. Formula Cu(C 3 N 3 H 6 )(OH)·(DMF)x·(H 2 O)y, wherein x ranges from 0 to 0.5 and y ranges from 0 to 0.2, the 3D hydrophobic MOF according to claim 1.

4. The 3D hydrophobic MOF according to claim 1, wherein the Cu has an oxidation state of +1.

5. CO 2 / N 2 The selectivity is approximately 300, and CO2 at room temperature. 2 The pores have an optimal concentration of charge-balanced hydroxide ions to ensure that uptake is definitely >3 mmol / g, and contain zero to >3 mmol of CO 2 The 3D hydrophobic MOF according to claim 1 is in the same state as described above.

6. A 3D hydrophobic MOF according to any one of claims 1 to 4, which is stable up to 280°C.

7. A method for synthesizing a 3D hydrophobic MOF according to any one of claims 1 to 4, a. A step of inducing a solvothermal reaction between copper nitrate trihydrate, melamine, and terephthalic acid in an organic solvent, followed by cooling to room temperature to obtain the reaction product; b. A step of filtering the reaction product to obtain block-type pale green crystals of 3D hydrophobic MOF; c. The steps of ultrasonically decomposing the block-type pale green crystals in an organic solvent, followed by filtration to remove unreacted terephthalic acid; d. A step of washing with a large amount of alkanol to obtain the 3D hydrophobic MOF, A method that includes this.

8. The method according to claim 7, wherein the ratio of copper nitrate trihydrate to melamine is 0.1:1 to 1:0.1, respectively.

9. The method according to claim 7, wherein the ratio of copper nitrate trihydrate to melamine is 1:1, respectively.

10. The method according to claim 7, wherein the ratio of copper nitrate trihydrate to melamine is 0.1 mmol:0.1 mmol, respectively.

11. The method according to claim 7, wherein the terephthalic acid concentration is 0.1 to 1 mmol.

12. The method according to claim 7, wherein the solvothermal reaction is induced at 90°C to 150°C for 48 to 96 hours.

13. CO 2 A method for adsorbing, a. A 3D hydrophobic MOF according to any one of claims 1 to 4 is H 2 O, CO 2 ,CH 4 , N 2 , H 2 CO 2 The process involves the deposition of the material onto the MOF; b. Next CO 2 For the sorption cycle, a step is taken to optionally regenerate the 3D hydrophobic MOF, Methods that include...

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