Preparation method and application of amino-functionalized metal organic framework material

Abstract

The invention belongs to the field of metal organic framework materials in greenhouse gas adsorption, and particularly relates to a preparation method and application of an amino-functionalized metal organic framework material. According to the amino-functionalized organic framework material (UIO-67-NH2), an amino functional group is introduced into the structure of a 4, 4 '-diphenyldicarboxylic acid ligand, and compared with a metal framework organic material (UIO-67) without the functional group, the UIO-67-NH2 material has the advantage that more active sites are increased, so that the capability of selective carbon dioxide is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of greenhouse gas adsorption of metal organic framework materials, and specifically relates to a preparation method and application of an amino-functionalized organic framework material. Background Art

[0002] The large-scale emission of carbon dioxide is one of the main causes of global warming, so it is of great research significance to find efficient, low-energy and environmentally friendly carbon dioxide capture technology. Metal-organic framework materials are widely used in the field of gas adsorption and separation due to their unique pore structure and surface properties. However, in the adsorption process of carbon dioxide and other gases, metal-organic framework materials require high additional energy for desorption, which limits their application in this field. Therefore, designing and preparing metal-organic framework materials with special adsorption functions is an effective way to solve this problem. Summary of the invention

[0003] Based on the above reasons, the first technical scheme of the present application discloses a method for preparing an amino-functionalized metal-organic framework material, comprising the following steps: adding 2-amino-4,4′-biphenyldicarboxylic acid and zirconium tetrachloride to N,N'-dimethylformamide, then adding acetic acid and triethylamine, reacting at 100-150°C for 12-48h, washing, drying, and solvent exchange activation to obtain an amino-functionalized metal-organic framework material, namely, UIO-67-NH2 material.

[0004] Furthermore, the mass ratio of the 2-amino-4,4′-biphenyldicarboxylic acid to zirconium oxychloride is 1:1-3:1.

[0005] Furthermore, the solvent exchange activation is specifically to exchange the methanol solvent and then perform vacuum activation at 100-160° C. for 4-8 hours to obtain the activated material.

[0006] And, the UIO-67-NH2 material prepared according to the above preparation method and its application in the adsorption of greenhouse gases; preferably, the application of the UIO-67-NH2 in the selective adsorption of carbon dioxide.

[0007] The beneficial effects of the present invention are:

[0008] The amino-functionalized organic framework material (UIO-67-NH2) described in the present application introduces an amino functional group into the structure of the 4,4'-biphenyldicarboxylic acid ligand, which increases the surface area of ​​the material and provides more active sites compared to the metal framework organic material (UIO-67) without introducing functional groups, thereby improving the ability to selectively adsorb gaseous carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1This is the scanning electron microscope image of UIO-67 material;

[0010] Figure 2 This is the scanning electron microscope image of UIO-67-NH2 material;

[0011] Figure 3 XRD powder diffraction spectra of UIO-67 material and UIO-67-NH2 material;

[0012] Figure 4 FT-IR infrared spectra of UIO-67 material and UIO-67-NH2 material;

[0013] Figure 5 This is the thermogravimetric analysis curve of UIO-67-NH2 material;

[0014] Figure 6 N2 adsorption-desorption isotherm of UIO-67-NH2 material at 77K;

[0015] Figure 7 This is the adsorption-desorption isotherm of UIO-67-NH2 material for CO2 and CH4 at 298K. DETAILED DESCRIPTION

[0016] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0017] The first embodiment of the present application discloses a method for preparing an amino-functionalized metal-organic framework material, comprising the following steps: adding 2-amino-4,4′-biphenyl dicarboxylic acid and zirconium tetrachloride to N,N′-dimethylformamide, then adding acetic acid and triethylamine, reacting at 100-150°C for 12-48h, washing, drying, and solvent exchange activation to obtain an amino-functionalized metal-organic framework material, i.e., UIO-67-NH2 material; the mass ratio of the 2-amino-4,4′-biphenyl dicarboxylic acid to the zirconium tetrachloride is 1:1-3:1; the solvent exchange activation is specifically a methanol solvent exchange, followed by vacuum activation at 100-160°C for 4-8h to obtain an activated material.

[0018] It is understood that in this embodiment, in order to remove the solvent on the surface of the reaction product, the reaction product needs to be washed, dried, etc., which is conventionally known to those skilled in the art, and this application only provides a preferred embodiment. Acetic acid and triethylamine act as catalysts to adjust the pH.

[0019] In some preferred embodiments, the reaction product is dried at 100°C for 24 hours, washed with (DMF) N, N'-dimethylformamide and centrifuged for 10 minutes three times, soaked in 10 ml of methanol for 10 minutes, and placed for three days (72 hours) with the soaking solution replaced every 24 hours. Finally, it is placed in a vacuum drying oven at 100°C for 4 hours to obtain the amino-functionalized organic framework material (UIO-67-NH2) described in the present application.

[0020] It should be noted that the UIO-67-NH2 obtained in the present application has better thermal stability than UIO-67 that has not been functionalized with amino groups, and can therefore withstand a higher activation temperature. In the art, the process of removing solvent molecules from metal-organic framework materials is called the activation of metal-organic framework materials. Generally speaking, the higher the activation temperature, the better the removal effect of solvent molecules. The activation temperature of UIO-67 that has not been functionalized with amino groups is generally around 150°C, and the UIO-67-NH2 prepared in the present application has higher thermal stability, and its activation at around 160°C will not break the material skeleton, thereby ensuring that the solvent molecules are completely removed and the material is intact while also increasing the gas storage capacity of UIO-67-NH2, thereby improving the adsorption performance.

[0021] The preparation method of the material of the present application and its effects will be described more clearly and completely below in conjunction with the accompanying drawings and specific embodiments.

[0022] Experimental Example 1 Preparation of amino-functionalized organic framework material (UIO-67-NH2)

[0023] 2-amino 4,4'-biphenyl dicarboxylic acid (0.095g) and zirconium tetrachloride (0.067g) were placed in a 25ml polytetrafluoroethylene reactor liner (ppl), and 7.5mL of (DMF) N, N'-dimethylformamide were added respectively and the mixture was ultrasonically treated for 20min, and dissolved. Then 1.4mL of acetic acid was added and 0.1mL of triethylamine was transferred with a pipette. Then it was placed in a polytetrafluoroethylene reactor liner (PPL) at 120℃, and the polytetrafluoroethylene reactor liner (PPL) was placed in a stainless steel reaction container for reaction for 24 hours, and then vacuum dried at 100℃ for 24 hours, washed with (DMF) N, N'-dimethylformamide and centrifuged for 10 minutes, repeated three times, and 10ml of methanol was taken for immersion in ultrasound for 10 minutes, and the immersion solution was replaced every 24 hours for three days (72 hours). Finally, it was placed in a vacuum drying oven at a temperature of 100℃ for 4 hours. Nano UIO-67-NH2 was obtained. Finally, the obtained material was placed in a test tube, vacuum activated at 160° C. for 4 hours, and then stored in a desiccator.

[0024] Comparative Example 1 Preparation of organic framework material (UIO-67)

[0025] 4,4'-biphenyldicarboxylic acid (0.090g) and zirconium tetrachloride ZrCl4 (0.067g) were placed in a 50mL polytetrafluoroethylene reaction container liner (ppl) and 15mL (DMF) N, N'-dimethylformamide and 3mL glacial acetic acid were added. After the cap was sealed and ultrasonicated for 15 minutes to dissolve, the polytetrafluoroethylene (PPL) liner was placed in a stainless steel reaction container and heated at 120°C for 24 hours in a vacuum. After the heating reaction was completed, it was taken out and placed outdoors to cool to room temperature. First, it was washed with N, N'-dimethylformamide (DMF) and centrifuged for 10 minutes, repeated 3 times, and then washed with acetone and centrifuged for 5 minutes, repeated 3 times. Finally, it was dried in a vacuum drying oven at a temperature of 85°C for 4 hours to obtain UIO-67 material. Finally, the obtained material was placed in a test tube and vacuum activated at 150°C for 4 hours and then stored in a drying vessel.

[0026] Test Example 1 Characterization of morphology, structure and performance

[0027] The materials prepared in Example 1 and Comparative Example 1 were subjected to electron microscope scanning, X-ray diffractometer, thermogravimetric analyzer, infrared spectrometer and other morphological and structural characterizations.

[0028] The experimental results are as follows Figure 1-4 As shown, Figure 1 , Figure 2 The electron microscope scanning images of the materials of Example 1 and Comparative Example 1 are shown in the figure. Figure 1 (Scanning electron microscope image of UIO-67 material in comparative example 1) It can be seen intuitively that the porosity distribution and shape of the UIO-67 metal organic framework (MOFs) material are a regular octahedral crystal with regular morphology and high crystallinity. Figure 2 (Scanning electron microscope image of UiO-67-NH2 material in Example 1) It can be seen that the prepared UiO-67-NH2 is in the shape of an irregular sphere, and has denser porosity and higher crystallinity than the SEM scanning image of the UIO-67 metal organic framework (MOFs) material, proving that the UIO-67-NH2 prepared in the present application has more active sites, thereby increasing the ability to selectively adsorb carbon dioxide gas.

[0029] Figure 3The XRD powder diffraction spectra of the materials of Example 1 (UIO-67-NH2) and Comparative Example 1 (UIO-67) are shown in the figure. It can be seen from the figure that the positions of the characteristic absorption peaks of the two materials of Example 1 and Comparative Example 1 (i.e. before and after amino functionalization) and the characteristic absorption peaks of the simulated spectral data are basically consistent, and the positions of the characteristic absorption peaks are stable, indicating that the crystal structure of the prepared UIO-67 material has been successfully synthesized. It shows that the diffraction peaks of the prepared materials can report peaks that are associated with known ones, so the product is pure, indicating that the amino groups grafted on the ligands have not changed the crystal structure of UIO-67. However, the peak intensity of UIO-67-NH2 is reduced, and the peak intensity is reduced more after activation, indicating that the morphological regularity of the amino-functionalized material decreases. It also shows that the thermal stability and chemical stability of the UIO-67 material are relatively excellent. The thermal stability and chemical stability of UIO-67-NH2 are also improved to a certain extent.

[0030] Figure 4 The FT-IR infrared spectra of Example 1 (UIO-67-NH2) and Comparative Example 1 (UIO-67) are shown in Figure 1. It can be seen from the figure that the amino-modified UIO-67-NH2 has a peak at 3500 cm -1 There are strong absorption peaks near the surface of the NH2 and two peaks with the same intensity at 1600cm-1 and 1300cm-1. -1 The strong absorption peak is CN absorption, which indicates that the amino group on the ligand was not destroyed during the synthesis process and the amino group was successfully modified on the UIO-67-NH2 material.

[0031] From the above experimental results, it can be seen that the preparation method of the present application can successfully synthesize amino-functionalized organic framework materials (UIO-67-NH2), and compared with UIO-67 that is not amino-functionalized, it has more active sites, so that the selective adsorption ability of UIO-67-NH2 is significantly better than that of UIO-67.

[0032] Test Example 2 Example 1 UIO-67-NH2 Thermogravimetric Analysis

[0033] Figure 5 This is the thermogravimetric analysis curve of the UIO-67-NH2 material prepared in Example 1. This experiment uses TGA to examine the thermal stability of the material in nitrogen (N2). Figure 5 It can be seen that the temperature of UiO-67-NH2 material rapidly decreased by about 10% at 50℃-100℃, which was attributed to the loss of guest solvent molecules; then the TGA curve gradually decreased, and the skeleton of the material began to collapse after reaching 550℃;

[0034] Test Example 3 Gas Adsorption Capacity Analysis

[0035] Figure 6The N2 adsorption-desorption isotherm of the UIO-67-NH2 material prepared in Example 1 at 77K shows that the maximum adsorption capacity of UIO-67-NH2 is 361.34 cm 3 / g, and its BET specific surface area is 922.33m 2 / g, and the pore size is 2.42nm.

[0036] Figure 7 The adsorption-desorption isotherms of CO2 and CH4 of the UIO-67-NH2 material prepared in Example 1 show that the adsorption capacity of CO2 by the UIO-67-NH2 material is 21.5 cm-1 at 1 atmospheric pressure and 298 K. 3 / g(STP), the adsorption capacity of CH4 is 5.25cm 3 / g(STP), and its selectivity coefficient is 65:35, indicating that UIO-67-NH2 can efficiently and selectively adsorb carbon dioxide.

[0037] From the above, it can be seen that the UIO-67-NH2 material prepared by the technical solution of the present application can effectively improve the adsorption capacity for conventional gases and has selective adsorption performance for carbon dioxide.

[0038] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

Claims

1. A method for preparing an amino-functionalized metal organic framework material, characterized in that: The method comprises the following steps: adding 2-amino-4,4′-biphenyldicarboxylic acid and zirconium tetrachloride to N,N′-dimethylformamide, then adding acetic acid and triethylamine, reacting at 100-150° C. for 12-48 hours, washing, drying, and solvent exchange activation to obtain an amino-functionalized metal organic framework material, namely, UIO-67-NH2 material.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the 2-amino-4,4′-biphenyldicarboxylic acid to zirconium oxychloride is 1:1-3:

1.

3. The preparation method according to claim 1, characterized in that: The solvent exchange activation specifically includes methanol solvent exchange and vacuum activation at 100-160° C. for 4-8 hours to obtain an activated material.

4. A UIO-67-NH2 material prepared according to any one of the preparation methods of claims 1-3.

5. Use of the UIO-67-NH2 material according to claim 4 in greenhouse gas adsorption.

6. The use according to claim 5, characterized in that: The application of UIO-67-NH2 in the selective adsorption of carbon dioxide.

Images