Polydivinylbenzene-coated amine-functionalized metal-organic framework based carbon dioxide adsorbents

Abstract

The present invention relates to a polydivinylbenzene-coated amine-functionalized metal-organic framework-based carbon dioxide adsorbent. According to the present invention, it is possible to provide a carbon dioxide adsorbent that maintains its adsorption performance even in flue gas environments containing high concentrations of moisture and has improved reusability and stability.

Description

Technology Field

[0001] The present invention relates to a polydivinylbenzene-coated amine-functionalized metal-organic framework-based carbon dioxide adsorbent. Background Technology

[0002] Metal-organic frameworks (MOFs) are crystalline solids formed by the coordination bonding of metals and ligands. They have the advantage of having a large surface area and the ability to control pores, so research is underway to use them as CO2 adsorbents. Recently, it has been reported that MOFs with introduced amine groups, such as diamines, have significantly improved carbon dioxide adsorption capacity through chemical bonding between the amine group and the carbon atoms of carbon dioxide.

[0003] Meanwhile, flue gas from thermal power plants, which is a major source of CO2, the primary cause of global warming, contains about 5–10% moisture in addition to 10–15% carbon dioxide. Continuous exposure to such moisture can cause the breakdown of MOF frameworks and lead to a decrease in coordinated amines, which not only reduces carbon dioxide adsorption capacity but also significantly lowers reusability. Therefore, in order to apply MOFs to actual carbon dioxide capture processes, it is required to develop a technology that can maintain the adsorption performance of the adsorbent even in flue gas environments containing high concentrations of moisture, improve reusability and stability, and reduce adsorption-desorption energy by lowering the desorption temperature. Prior art literature

[0004] Republic of Korea Registered Patent No. 10-2028613 The problem to be solved

[0005] The present invention was devised to solve the aforementioned problems, and the objective of the present invention is to provide a polydivinylbenzene-coated amine-functionalized metal-organic framework-based carbon dioxide adsorbent that maintains the adsorption performance of the adsorbent even in flue gas environments containing high concentrations of moisture and improves reusability and stability. means of solving the problem

[0006] In order to solve the above problem, the present invention,

[0007] A carbon dioxide adsorbent is provided comprising: a metal-organic framework in which a polyvalent amine is introduced at an open metal site; and polydivinylbenzene (PDVB) coated on the surface of the metal-organic framework.

[0008] According to the present invention, the metal-organic framework may be selected from the group consisting of M2(dobpdc), M2(dobdc), M2(o-dobdc), M2(m-dobdc), M2(dondc), M2(dotpdc), and M2(hob):

[0009] Here, metal M is Mg, Ti, V, Cr, Mn, Fe, Co, Ni, Cu or Zn, dobpdc is 4,4'-dioxido-3,3'-biphenyldicarboxylate, dobdc is 2,5-dioxido-1,4-benzenedicarboxylate, o-dobdc is 4,5-dioxido-1,2-benzenedicarboxylate, m-dobdc is 4,6-dioxido-1,3-benzenedicarboxylate, dondc is 1,5-dioxide-2,6-naphthalenedicarboxylate, dotpdc is 4,4'-dioxido-3,3'-triphenyldicarboxylate, and hob is 5,5'-diagendiylbis(2-oxydobenzoate).

[0010] According to the present invention, the content of the PDVB may be 3 to 8 parts by weight based on 100 parts by weight of the metal-organic framework.

[0011] According to the present invention, the polyvalent amine may be a compound represented by the following [Chemical Formula I]:

[0012] [Chemical Formula I]

[0013]

[0014] In the above [Chemical Formula I],

[0015] R1, R2, R4, and R5 are each independently hydrogen, -F, -Cl, -Br, -CN, -NO2, -OH, -CN, substituted or unsubstituted C1-C 30 Alkyl, or -(CH2) p NR a R b And,

[0016] R3, R6, and R7 are each independently hydrogen, hydroxyl, substituted, or unsubstituted C1-C 30 Alkyl, or -(CH2) p NR a R b is,

[0017] l and n are each independently integers from 1 to 10, and

[0018] p are each independently integers from 0 to 10, and

[0019] m is 0 or 1, and

[0020] R a , R b Each is independently hydrogen, or substituted or unsubstituted C1-C 30 It is an alkyl.

[0021] In addition, the compound represented by [Chemical Formula I] above may be selected from the compounds represented by the following Chemical Formulas 1 to 6:

[0022]

[0023] Here, n is an integer from 1 to 10.

[0024] In addition, the compound represented by the above [Chemical Formula I] may be selected from Ethylethylenediamine (een), 2-(2-aminoethylamino)ethanol, 1-(2-aminoethyl)piperazine, 2-(aminomethyl)piperidine, N-benzylethylenediamine, polyethyleneimine, ethylenediamine, N-methylethylenediamine (men), and N,N'-dimethylethylenediamine (mmen).

[0025] According to the present invention, the carbon dioxide adsorbent may be formed in the form of a membrane.

[0026] According to the present invention, the carbon dioxide adsorbent may be coated on a predetermined substrate.

[0028] The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

[0029] Prior to this, terms and words used in this specification and claims shall not be interpreted in their ordinary and dictionary meanings, but must be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor may appropriately define the concept of the terms to best describe his invention. Effects of the invention

[0030] According to the present invention, it is possible to provide a carbon dioxide adsorbent that maintains its adsorption performance even in flue gas environments containing high concentrations of moisture and has improved reusability and stability. Brief explanation of the drawing

[0031] FIG. 1 shows (a) the synthesis process of polydivinylbenzene used in the present invention, (b) the measurement result of the moisture contact angle of polydivinylbenzene, (c) a photograph of the moisture contact angle of polydivinylbenzene, and (d) the nitrogen adsorption isotherm of polydivinylbenzene. Figure 2 shows the synthesis process of MOF / PDVB-X. Figure 3 shows (a) the PXRD graph, (b) the IR spectrum, and (c) the nitrogen adsorption isotherm of MOF / PDVB. Figure 4 shows the results of measuring the moisture contact angles of (a) Mg2(dobpdc), (b) MOF / PDVB-1, (c) MOF / PDVB-3, (d) MOF / PDVB-5, and (e) the moisture adsorption isotherm at 25°C. Figure 5 shows the TEM analysis results and line scan results for (ad) Mg2(dobpdc), (eh) MOF / PDVB-1, (il) MOF / PDVB-3, and (mp) MOF / PDVB-5. Figure 6 shows the synthesis process of een-MOF / PDVB-X. Figure 7 shows (a) the PXRD graph, (b) the IR spectrum, and (c) the nitrogen adsorption isotherm of een-MOF / PDVB. Figure 8 shows the carbon dioxide adsorption isotherms at various temperatures for (a) een-MOF, (b) een-MOF / PDVB-1, (c) een-MOF / PDVB-3, and (d) een-MOF / PDVB-5. Figure 9 shows (a) the moisture contact angle results of een-MOF, (b) een-MOF / PDVB-1, (c) een-MOF / PDVB-3, (d) een-MOF / PDVB-5, and (e) the moisture adsorption isotherm at 25°C. Figure 10 shows the TPD analysis results of (a) een-MOF, (b) een-MOF / PDVB-1, (c) een-MOF / PDVB-3, and (d) een-MOF / PDVB-5 in a moisture-containing environment. Figure 11 shows (a) the results of a long-term exposure test for een-MOF and een-MOF / PDVB at 90% relative humidity, and (b) the results of a repeated adsorption-desorption behavior test for een-MOF and een-MOF / PDVB at 90% relative humidity and flue gas conditions. Figure 12 shows the carbon dioxide breakthrough curves at 90% relative humidity for (a) een-MOF and (b) een-MOF / PDVB-5. Figure 13 shows (a) the synthesis process of mmen-MOF / PDVB-5, (b) the measurement results of the moisture contact angle of mmen-MOF, (c) the measurement results of the moisture contact angle of mmen-MOF / PDVB-5, and (d) the results of a long-term exposure test of mmen-MOF / PDVB-5 at 90% relative humidity. Specific details for implementing the invention

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by a skilled expert in the art to which this invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

[0034] The present invention aims to provide a polydivinylbenzene-coated amine-functionalized metal-organic framework-based carbon dioxide adsorbent that maintains the adsorption performance of the adsorbent even in flue gas environments containing high concentrations of moisture, and improves reusability and stability.

[0035] Specifically, the present invention provides a carbon dioxide adsorbent with improved reusability and stability in flue gas environments containing high moisture concentrations (90% relative humidity) by growing polydivinylbenzene (PDVB) of various thicknesses on the surface of a metal-organic framework (MOF).

[0036] To this end, the present invention provides a carbon dioxide adsorbent comprising: a metal-organic framework in which a polyvalent amine is introduced at an open metal site; and polydivinylbenzene (PDVB) coated on the surface of the metal-organic framework.

[0037] The metal-organic framework according to the present invention may be selected from the group consisting of M2(dobpdc), M2(dobdc), M2(o-dobdc), M2(m-dobdc), M2(dondc), M2(dotpdc), and M2(hob). In this case, the metal M may be Mg, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, or Zn, and preferably may be Mg. Additionally, dobpdc is 4,4'-deoxydo-3,3'-biphenyldicarboxylate, dobdc is 2,5-deoxydo-1,4-benzenedicarboxylate, o-dobdc is 4,5-deoxydo-1,2-benzenedicarboxylate, m-dobdc is 4,6-deoxydo-1,3-benzenedicarboxylate, dondc is 1,5-dioxide-2,6-naphthalenedicarboxylate, dotpdc is 4,4'-deoxydo-3,3'-triphenyldicarboxylate, and hob may be 5,5'-diagendiylbis(2-oxydobenzoate), and the organic ligands used in the present invention H4dobdc, H4(m-dobdc), H4dondc, H4hob, H4dobpdc, H4dotpdc can be expressed as [Organic Liland] below.

[0038] [Organic Ligand]

[0039]

[0040] In the present invention, to improve reusability and stability in flue gas environments containing high concentrations of moisture, polydivinylbenzene of various thicknesses was grown on the surface of an MOF. As can be seen from the results of the following examples, the content of PDVB is preferably 3 to 8 parts by weight based on 100 parts by weight of the metal-organic framework, and more preferably 4 to 7 parts by weight. If the content of PDVB is below the lower limit, the effect of improving hydrophobicity and the reusability and stability of the MOF is negligible, and if it exceeds the upper limit, there is a problem that the performance improvement effect is not further enhanced.

[0041] In addition, the polyvalent amine introduced into the porous metal-organic framework of the present invention may include one or more primary to tertiary amine groups, and through the amine functionalization of such porous metal-organic framework, the carbon dioxide adsorbent can capture carbon dioxide at low concentrations. In particular, for capturing carbon dioxide from air, it is preferable to use a porous metal-organic framework in which a high density of amine groups is introduced into the cavities. Through the introduction of such a high density of amine groups, the adsorption enthalpy due to the interaction between the amine groups and the carbon atoms of CO2 can be significantly improved. This amine functionalization is achieved by grafting amine groups onto open metal sites of the porous metal-organic framework, where the open metal sites act as Lewis acids. In this case, the primary amine group can coordinate well with the open metal sites by including two hydrogen groups. Furthermore, the remaining free amine groups can effectively capture CO2 entering the cavities.

[0042] Specifically, the polyvalent amine may be a compound represented by the following [Chemical Formula 1]:

[0043] [Chemical Formula I]

[0044]

[0045] In the above [Chemical Formula I],

[0046] R1, R2, R4, and R5 are each independently hydrogen, -F, -Cl, -Br, -CN, -NO2, -OH, -CN, substituted or unsubstituted C1-C 30 Alkyl, or -(CH2) p NR a R b And,

[0047] R3, R6, and R7 are each independently hydrogen, hydroxyl, substituted, or unsubstituted C1-C 30 Alkyl, or -(CH2) p NR a R b is,

[0048] l and n are each independently integers from 1 to 10, and

[0049] p are each independently integers from 0 to 10, and

[0050] m is 0 or 1, and

[0051] R a , R b Each is independently hydrogen, or substituted or unsubstituted C1-C 30 It is an alkyl.

[0052] In addition, the compound represented by [Chemical Formula I] above may be selected from the compounds represented by the following Chemical Formulas 1 to 6:

[0053]

[0054] Here, n is an integer from 1 to 10.

[0055] More specifically, the polyamine may be selected from ethylethylenediamine (een) ([Formula 1]), 2-(2-aminoethylamino)ethanol ([Formula 2]), 1-(2-aminoethyl)piperazine ([Formula 3]), 2-(aminomethyl)piperidine ([Formula 4]), N-benzylethylenediamine ([Formula 5]), polyethyleneimine ([Formula 6]), ethylenediamine, N-methylethylenediamine (men), and N,N'-dimethylethylenediamine (mmen).

[0056] According to the present invention, an amine-functionalized metal-organic framework coated with polydivinylbenzene can be used as a carbon dioxide adsorbent for air purification in the form of a composite membrane for carbon dioxide adsorption, or coated on a Ti mesh, an air purification filter, or activated carbon.

[0057] Specifically, the carbon dioxide adsorbent according to the present invention may be formed in the form of a membrane. Additionally, the carbon dioxide adsorbent may be coated and used on a predetermined substrate, wherein the substrate may be a Ti mesh, a filter, or active carbon (AC).

[0058] In addition, through the following examples, the present invention has confirmed that it is possible to provide a carbon dioxide adsorbent that maintains adsorption performance and has improved reusability and stability even in flue gas environments containing high concentrations of moisture.

[0060] [Example]

[0061] The present invention will be described in more detail below through examples. These examples are solely for illustrating the present invention, and it will be obvious to those skilled in the art that the scope of the present invention is not to be interpreted as being limited by these examples. Accordingly, the actual scope of the present invention is defined by the appended claims and their equivalents.

[0063] Example. Preparation of a polydivinylbenzene-coated amine-functionalized metal-organic framework-based carbon dioxide adsorbent

[0064] Polydivinylbenzene (PDVB) is a polymer synthesized through the radical polymerization of the monomer divinylbenzene in the presence of the initiator 2,2-azobis(2-methylpropionitrile) (AIBN) (Fig. 1). PDVB is a porous polymer containing pores and exhibiting high hydrophobicity. Therefore, in this invention, it was expected that growing PDVB on the surface of an MOF would result in high hydrophobicity, and the monomer divinylbenzene was utilized to achieve a uniform coating on the surface. After mixing the MOF and the monomer, polymerization on the surface was attempted through the introduction of an additional initiator. The reaction was carried out by controlling the amount of divinylbenzene relative to the MOF, and as a result, MOF / PDVB-1, MOF / PDVB-3, and MOF / PDVB-5, which incorporated PDVB of various content, were synthesized.

[0066] Mg 2 Synthesis of (dobpdc)

[0067] 137 mg of H4dobpdc and 5 mg of MgCl230 were quantified, dissolved in 8 mL of DMF and 8 mL of EtOH, and reacted at 130°C for 30 minutes using a microwave apparatus to obtain a white solid product. The synthesized product was immersed in MeOH for 3 days, filtered, and vacuum dried to obtain Mg2(dobpdc) (hereinafter MOF).

[0069] Synthesis of MOF / PDVB-X (X=1,3,5)

[0070] 300 mg of the synthesized MOF was weighed and placed in a 100 mL round-bottom flask. Then, 15 mL of toluene and a certain amount of divinylbenzene were added, and the mixture was dispersed using a sonicator for 1 hour. Subsequently, a certain amount of the initiator 2,2-azobis(2-methylpropionitrile) (AIBN) was weighed and added. The round-bottom flask was connected to a reflux apparatus, and the reaction was carried out in an oil bath at 100°C for 24 hours. After the reaction, the product was filtered and washed with toluene and hexane. A solid powder was obtained and dried under vacuum for more than 12 hours. Depending on the amount of PDVB used in the reaction, the products were named MOF / PDVB-1 (0.111 mL, 4.11 mg), MOF / PDVB-3 (0.333 mL, 12.33 mg), and MOF / PDVB-5 (0.555 mL, 20.55 mg) (Fig. 2).

[0072] Synthesis of een-MOF / PDVB-X

[0073] 300 mg each of the synthesized MOF and MOF / PDVB-X were quantified and placed in a 100 mL round-bottom flask. N A solution of 4.2 mL of ethylethylenediamine (een) was prepared by dissolving it in toluene (30 mL). The een solution was transferred to a flask, and the MOF was reacted in an ultrasonic device at 50°C for 12 hours, while the MOF / PDVB was reacted in an oil bath at 50°C for 12 hours. After the reaction, the product was filtered and washed several times with toluene and hexane. Subsequently, the solid powder was dried under vacuum to obtain een-MOF and een-MOF / PDVB-X (Fig. 6).

[0075] Test Example 1. Characterization of MOF / PDVB-X

[0076] Characterization of the obtained MOF / PDVB-X was performed. Specifically, crystallinity was confirmed by powder X-ray diffraction (PXRD), and the polymerization of PDVB was confirmed through infrared spectroscopy (IR).

[0077] Figure 3 shows (a) the PXRD graph, (b) the IR spectrum, and (c) the nitrogen adsorption isotherm of MOF / PDVB.

[0078] First, powder X-ray diffraction analysis results showed that the MOF / PDVB composite exhibited the same pattern as the MOF (Fig. 3a). This confirmed that the MOF structure was unaffected by the radical polymerization reaction. Next, infrared spectroscopy revealed that at 2900 cm⁻¹ in the composite spectrum... -1 It was observed that a new peak corresponding to the nearby CH was generated, thereby confirming the formation of PDVB (Fig. 3b). In addition, porosity was confirmed through nitrogen adsorption, and it was confirmed that the specific surface area of ​​the composites decreased compared to the existing MOF, which is attributed to the additional weight increase caused by PDVB (Fig. 3c).

[0080] Figure 4 shows the results of measuring the moisture contact angles of (a) Mg2(dobpdc), (b) MOF / PDVB-1, (c) MOF / PDVB-3, (d) MOF / PDVB-5, and (e) the moisture adsorption isotherm at 25°C.

[0081] As shown in Fig. 4, MOF and MOF / PDVB-1 did not form a moisture contact angle, whereas MOF / PDVB-3 and MOF / PDVB-5 exhibited high moisture contact angles (Figs. 4a-d). Through these results, it was confirmed that the hydrophobic properties of MOF / PDVB-3 and MOF / PDVB-5, to which an appropriate amount of PDVB was introduced, were significantly improved. In addition, as a result of measuring the moisture adsorption curve at 25°C, it was confirmed that the MOF / PDVB composite material showed a lower adsorption amount compared to MOF, and that the hydrophobic properties were further improved as the PDVB content increased (Fig. 4e).

[0083] Figure 5 shows the TEM analysis results and line scan results for (ad) Mg2(dobpdc), (eh) MOF / PDVB-1, (il) MOF / PDVB-3, and (mp) MOF / PDVB-5.

[0084] As shown in Fig. 5, according to the present invention, a PDVB layer is well formed on the surface of the MOF, and it was confirmed that the PDVB layer formed on the surface gradually becomes thicker as the PDVB content increases. Through these results, it was confirmed that according to the present invention, a uniform PDVB layer is formed on the outside of the MOF structure through a radical polymerization reaction, and thereby the hydrophobic properties are significantly improved.

[0086] Test Example 2. Characteristics and Gas Adsorption Analysis of een-MOF / PDVB-X

[0087] Structural changes and een introduction were confirmed by measuring PXRD and IR on the synthesized een-MOF and een-MOF / PDVB.

[0088] Figure 7 shows (a) the PXRD graph, (b) the IR spectrum, and (c) the nitrogen adsorption isotherm of een-MOF / PDVB.

[0089] As shown in Fig. 7, no structural changes were observed even after the introduction of een (Fig. 7a), and the NH corresponding to een was 3300 cm -1It was observed in the vicinity (Fig. 7b), and it was confirmed that the specific surface area decreased after the introduction of the amine (Fig. 7c). Through these results, it was confirmed that the introduction of the amine into the MOF structure and the MOF / PDVB complex was successfully carried out.

[0091] Next, carbon dioxide adsorption was performed at various temperatures to evaluate the carbon dioxide removal performance of the een-MOF / PDVB composite.

[0092] Figure 8 shows the carbon dioxide adsorption isotherms at various temperatures for (a) een-MOF, (b) een-MOF / PDVB-1, (c) een-MOF / PDVB-3, and (d) een-MOF / PDVB-5.

[0093] As shown in Fig. 8, under carbon dioxide conditions of 15% partial pressure at the 25°C adsorption isotherm, een-MOF is 4.42 mmol·g -1 , een-MOF / PDVB-1 is 4.35 mmol·g -1 , een-MOF / PDVB-3 is 2.78 mmol·g -1 , een-MOF / PDVB-5 is 2.60 mmol·g -1 It was observed that the adsorption performance was slightly reduced compared to een-MOF due to the increased weight of the PDVB layer present on the MOF surface.

[0095] Test Example 3. Confirmation of hydrophobic properties of een-MOF / PDVB-X

[0096] To confirm the resistance of the amine-functionalized complex to moisture, the moisture contact angle and moisture adsorption curve were measured, and the results are shown in Fig. 9 below.

[0097] Figure 9 shows (a) the moisture contact angle results of een-MOF, (b) een-MOF / PDVB-1, (c) een-MOF / PDVB-3, (d) een-MOF / PDVB-5, and (e) the moisture adsorption isotherm at 25°C.

[0098] As shown in Figure 9, een-MOF and een-MOF / PDVB-1 exhibited hydrophilic properties, while een-MOF / PDVB-3 and een-MOF / PDVB-5 maintained high hydrophobicity even after amine functionalization. In the moisture adsorption curve at 25°C, een-MOF / PDVB-1 showed an adsorption pattern and adsorption performance similar to een-MOF, whereas een-MOF / PDVB-3 and een-MOF / PDVB-5 showed low adsorption performance due to their high hydrophobicity. In particular, een-MOF / PDVB-5 exhibited very low moisture adsorption, confirming that it maintained high hydrophobicity.

[0100] Next, the carbon dioxide adsorption behavior in an environment containing high moisture concentrations was confirmed through a Temperature-Programmed Desorption (TPD) experiment, and the results are shown in Figure 10 below. Specifically, 15% carbon dioxide was adsorbed onto each sample at 90% relative humidity, and the carbon dioxide and moisture generated during desorption were detected using a mass spectrometer. In addition, the stability against moisture was confirmed by analyzing the adsorption amount before and after measurement in a moisture-containing environment.

[0101] Figure 10 shows the TPD analysis results of (a) een-MOF, (b) een-MOF / PDVB-1, (c) een-MOF / PDVB-3, and (d) een-MOF / PDVB-5 in a moisture-containing environment.

[0102] As shown in Fig. 10, in the case of een-MOF and een-MOF / PDVB-1, the adsorption performance decreased significantly after exposure to a moisture-containing environment, and the adsorption performance under 90% relative humidity conditions was lower than that under dry conditions. This is attributed to the inhibition of the interaction between the MOF and carbon dioxide due to high concentrations of moisture. On the other hand, in the case of een-MOF / PDVB-3 and een-MOF / PDVB-5, the adsorption performance was maintained even after exposure to a moisture-containing environment, and the adsorption performance under 90% relative humidity conditions was similar to that under dry conditions. Through these results, it was confirmed that according to the present invention, hydrophobic characteristics are significantly improved, allowing for the selective removal of carbon dioxide even under 90% relative humidity conditions.

[0104] Test Example 4. Evaluation of stability in a flue gas environment containing high moisture concentration

[0105] The stability of each material was confirmed through a 7-day exposure test at 90% relative humidity, and the applicability of the material to the process was confirmed by conducting repeated measurements of the adsorption and desorption of 15% carbon dioxide under conditions of 90% relative humidity, and the results are shown in Figure 11 below.

[0106] Figure 11 shows (a) the results of a long-term exposure test for een-MOF and een-MOF / PDVB at 90% relative humidity, and (b) the results of a repeated adsorption-desorption behavior test for een-MOF and een-MOF / PDVB at 90% relative humidity and flue gas conditions.

[0107] As shown in Fig. 11, een-MOF and een-MOF / PDVB-1 showed a rapid decrease in performance during exposure tests, whereas een-MOF / PDVB-3 maintained 75% of the existing adsorption capacity during a 7-day exposure test, and it was confirmed that een-MOF / PDVB-5 exhibited similar adsorption performance even after 7 days of exposure. In addition, during 30 repeated measurements, een-MOF and een-MOF / PDVB-1 showed a significant decrease in performance due to amine loss, whereas een-MOF / PDVB-3 maintained 70% of the adsorption performance after 30 repeated measurements, and it was confirmed that een-MOF / PDVB-5 maintained its adsorption performance even during 30 repeated measurements. Through these results, it was confirmed that according to the present invention, stability is significantly improved even in flue gas environments containing high concentrations of moisture.

[0109] Next, a breakthrough test was conducted at 90% relative humidity to measure the separation capacity of carbon dioxide, and the results are shown in Figure 12 below.

[0110] Figure 12 shows the carbon dioxide breakthrough curves at 90% relative humidity for (a) een-MOF and (b) een-MOF / PDVB-5.

[0111] As shown in Fig. 12, in the case of een-MOF, the breakthrough time of carbon dioxide continuously decreased over three cycles in an environment of 90% relative humidity, whereas in the case of een-MOF / PDVB-5, the breakthrough time of carbon dioxide was maintained under the same conditions. Through these results, it was confirmed that according to the present invention, moisture stability is significantly improved, and carbon dioxide can be selectively separated even under conditions of 90% relative humidity.

[0113] Test Example 5. Evaluation of moisture stability according to the type of introduced polyvalent amine

[0114] mmen-MOF / PDVB-5 was synthesized by functionalizing N,N′-dimethylethylenediamine (mmen) into MOF / PDVB-5, and moisture stability was evaluated, and the results are shown in Figure 13 below.

[0115] Figure 13 shows (a) the synthesis process of mmen-MOF / PDVB-5, (b) the measurement results of the moisture contact angle of mmen-MOF, (c) the measurement results of the moisture contact angle of mmen-MOF / PDVB-5, and (d) the results of a long-term exposure test of mmen-MOF / PDVB-5 at 90% relative humidity.

[0116] As shown in Fig. 13, the synthesized mmen-MOF / PDVB-5 exhibited higher hydrophobicity compared to mmen-MOF (Figs. 13b-c), and it was confirmed that while mmen-MOF showed a significant decrease in performance when exposed to 90% relative humidity, mmen-MOF / PDVB-5 maintained its adsorption performance (Fig. 13d). Through these results, it was confirmed that the moisture stability of all porous metal-organic frameworks functionalized with various polyvalent amines was significantly improved when PDVB was introduced according to the present invention.

[0118] Foregoing, specific parts of the present invention have been described in detail. It will be apparent to those skilled in the art that such specific descriptions are merely preferred embodiments and do not limit the scope of the invention. Accordingly, the actual scope of the invention is defined by the appended claims and their equivalents.

Claims

Claim 1 A carbon dioxide adsorbent comprising: a metal-organic framework in which a polyvalent amine is introduced at an open metal site; and polydivinylbenzene (PDVB) coated on the surface of the metal-organic framework. Claim 2 A carbon dioxide adsorbent according to claim 1, wherein the metal-organic framework is selected from the group consisting of M2(dobpdc), M2(dobdc), M2(o-dobdc), M2(m-dobdc), M2(dondc), M2(dotpdc), and M2(hob): wherein metal M is Mg, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, or Zn, dobpdc is 4,4'-deoxydo-3,3'-biphenyldicarboxylate, dobdc is 2,5-deoxydo-1,4-benzenedicarboxylate, o-dobdc is 4,5-deoxydo-1,2-benzenedicarboxylate, m-dobdc is 4,6-deoxydo-1,3-benzenedicarboxylate, and dondc is 1,5-dioxide-2,6-naphthalene dicarboxylate, dotpdc is 4,4'-dioxide-3,3'-triphenyl dicarboxylate, and hob is 5,5'-diagendiylbis(2-oxydobenzoate). Claim 3 A carbon dioxide adsorbent according to claim 1, characterized in that the content of the PDVB is 3 to 8 parts by weight based on 100 parts by weight of the metal-organic framework. Claim 4 A carbon dioxide adsorbent according to claim 1, characterized in that the polyvalent amine is a compound represented by the following [Chemical Formula I]: [Chemical Formula I] In the above [Chemical Formula I], R1, R2, R4, and R5 are each independently hydrogen, -F, -Cl, -Br, -CN, -NO2, -OH, -CN, substituted or unsubstituted C1-C 30 Alkyl, or -(CH2) p NR a R b And, R3, R6, and R7 are each independently hydrogen, hydroxyl, substituted or unsubstituted C1-C 30 Alkyl, or -(CH2) p NR a R b and, l and n are each independently integers from 1 to 10, p is each independently integer from 0 to 10, m is 0 or 1, and R a , R b Each is independently hydrogen, or substituted or unsubstituted C1-C 30 It is an alkyl. Claim 5 A carbon dioxide adsorbent according to claim 4, wherein the compound represented by [Chemical Formula I] is selected from the compounds represented by the following Chemical Formulas 1 to 6: Here, n is an integer from 1 to 10. Claim 6 A carbon dioxide adsorbent according to claim 4, characterized in that the compound represented by [Chemical Formula I] is selected from Ethylethylenediamine (een), 2-(2-aminoethylamino)ethanol, 1-(2-aminoethyl)piperazine, 2-(aminomethyl)piperidine, N-benzylethylenediamine, polyethyleneimine, ethylenediamine, N-methylethylenediamine (men), and N,N'-dimethylethylenediamine (mmen). Claim 7 A carbon dioxide adsorbent according to claim 1, characterized in that the carbon dioxide adsorbent is formed in the form of a membrane. Claim 8 A carbon dioxide adsorbent according to claim 1, characterized in that the carbon dioxide adsorbent is coated on a predetermined substrate.

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