A cu-based metal-organic framework material nju-bai5, a preparation method and application thereof

Abstract

The application provides a Cu-based metal organic framework material NJU-Bai5, which is a columnar layer type metal organic framework material with one-dimensional channels formed by coordination self-assembly of a tetranuclear copper cluster and organic ligands N,N',N"-tris(carboxymethyl)-1,3,5-benzene triformamide TCMBT and 1,3-bis(4-pyridyl)propane bpp. The preparation process uses pure water as a solvent and does not use other organic solvents, thereby reducing environmental pollution; a stirring reflux method which is more suitable for industrial production or a hydrothermal method is used, so that the metal organic framework material becomes a potential MOF for industrial application and production; the synthesis temperature can be as low as 60 DEG C, the reaction temperature is low, the reaction energy consumption is reduced, and the reaction safety performance is improved; the synthesis time can be reduced to 5h, and the production efficiency is improved; the metal organic framework material has excellent water stability, has good water adsorption capacity in a relative humidity range of 20-30%, can perform efficient air water collection, and is a potential material for realizing industrial application and production.

Description

Technical Field

[0001] This invention belongs to the field of porous adsorption materials research, specifically relating to a Cu-based metal-organic framework material NJU-Bai5, its preparation method and its application. Background Technology

[0002] Metal-organic frameworks (MOFs) are crystalline materials with permanent pores, formed by coordination interactions between metal clusters and organic ligands. The diversity of structures is achieved through the multiple coordination capabilities of metal clusters and the substitution of different substituents and various connection modes of the organic ligands. Because MOFs can adsorb different gases or organic molecules within their pores, they have shown broad application prospects in gas storage and separation, photocatalysis, drug delivery, and air-water harvesting.

[0003] Currently, the vast majority of MOFs are synthesized via solvothermal methods, and the solvents commonly used in MOF synthesis, such as N,N-dimethylformamide (DMF), N,N-diethylformamide (DEF), and dimethyl sulfoxide (DMSO), possess inherent toxicity and flammability. Furthermore, the high temperature, high pressure, and long reaction time involved in the synthesis are also major obstacles limiting the large-scale application of MOFs. Summary of the Invention

[0004] In order to overcome the above-mentioned defects and deficiencies in the prior art, this invention provides a Cu-based metal-organic framework material NJU-Bai5, its preparation method and its application. A copper-based MOF material NJU-Bai5 with high water stability is prepared in a pure water solvent at a relatively low temperature.

[0005] To solve the above technical problems:

[0006] The first objective of this invention is to provide a Cu-based metal-organic framework material, NJU-Bai5, which is a columnar metal-organic framework material with one-dimensional channels formed by coordination self-assembly of a tetranuclear copper cluster and organic ligands N,N',N''-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 1,3-bis(4-pyridyl)propane (bpp). This material has a specific surface area of ​​764 m². 2 / g, pore volume 0.25 cm³ 3 / g, possessing excellent water vapor adsorption performance and superior water adsorption cycle stability, can efficiently collect water from the air to solve the problem of drinking water shortage in arid areas.

[0007] The second objective of this invention is to provide a method for preparing a Cu-based metal-organic framework material NJU-Bai5, comprising the following steps: mixing copper salt, N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide TCMBT and 1,3-bis(4-pyridyl)propane bpp in pure water, treating the mixture by hydrothermal method or reflux stirring method, and washing and drying the mixture after the reaction to obtain the metal-organic framework material NJU-Bai5.

[0008] Furthermore, copper salts include copper nitrate, copper chloride, copper sulfate, and copper acetate, among others.

[0009] Furthermore, the ratio of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) to pure water is 1 mmol: (10~150) mL.

[0010] Furthermore, the molar ratio of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide TCMBT to 1,3-bis(4-pyridyl)propane bpp is 1:1 to 1:4.

[0011] Furthermore, the molar ratio of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) to copper salt is 1:1 to 1:4.

[0012] Furthermore, the treatment temperature for the hydrothermal method or the reflux stirring method is 50℃~100℃, and the treatment time is 2~12h.

[0013] A third objective of this invention is to provide an application of the above-mentioned Cu-based metal-organic framework material NJU-Bai5, or the Cu-based metal-organic framework material NJU-Bai5 obtained by the above preparation method, in air-water collection.

[0014] The beneficial technical effects achieved by this invention are as follows:

[0015] (1) This invention uses pure water as a solvent and does not use other organic solvents, thus reducing environmental pollution;

[0016] (2) The present invention adopts a stirring and reflux method that is more in line with industrial production or hydrothermal method, making it a potential MOF suitable for industrial mass production;

[0017] (3) The synthesis temperature selected in the preparation by stirring and reflux in this invention can be as low as 30°C. The low reaction temperature not only reduces the energy consumption of the reaction, but also improves the safety performance of the reaction.

[0018] (4) The synthesis time required by the present invention can be reduced to 2 hours, which improves the production efficiency;

[0019] (5) This metal-organic framework material has excellent water stability and good water adsorption capacity in the range of low relative humidity of 20-30%, which can carry out efficient air water collection and is a potential material for industrial-grade application production. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the ligand and crystal structure of NJU-Bai5 in this invention;

[0021] Figure 2 The diagrams show the nitrogen adsorption and BET linear region diagrams of NJU-Bai5 at 77K, where a is the nitrogen adsorption diagram at 77K and b is the BET linear region diagram.

[0022] Figure 3 This is a schematic diagram of two synthesis methods for NJU-Bai5 of the present invention;

[0023] Figure 4 The following are the characterization results of the embodiments of the invention, where a is a PXRD pattern, b is a 77 K nitrogen adsorption pattern, and c is a SEM image;

[0024] Figure 5 The figures are the isotherm diagrams of 5-round circulating water adsorption and 20-round two-point water adsorption cycles at 298K for Examples 5 and 8 of the present invention, respectively. Wherein a and b are the isotherm diagrams of 5-round circulating water adsorption and 20-round two-point water adsorption cycles at 298K for Example 8, respectively, and c and d are the isotherm diagrams of 5-round circulating water adsorption and 20-round two-point water adsorption cycles at 298K for Example 5, respectively. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments. These embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] This invention provides a Cu-based metal-organic framework material, NJU-Bai5. This NJU-Bai5 is a columnar metal-organic framework with one-dimensional channels formed by coordination self-assembly of a tetranuclear copper cluster and the organic ligands N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 1,3-bis(4-pyridyl)propane (bpp). A schematic diagram of its structure is shown below. Figure 1 As shown. Four copper atoms form as follows. Figure 1 The tetranuclear copper cluster {[Cu4( ]} is shown in the figure. µ 3-OH)2] 6+ Each quad-core copper cluster is associated with three such... Figure 1The TCMBT ligand linkage shown in c forms a structure as follows: Figure 1 The two-dimensional layered network shown in d, and then combined with... Figure 1 The b in the diagram represents a two-linkage structure of bpp ligands. These bpp ligands act as connecting pillars, linking adjacent layered networks to form a pillar-layered three-dimensional network structure with two types of one-dimensional channels: 3–6 Å and 3–4.5 Å. Figure 1 As shown in 'e', ​​Cu is blue, O is red, C is gray, N is dark blue, and H atoms are omitted. The specific surface area of ​​this material was calculated to be 764 m² using a nitrogen adsorption test curve at 77 K. 2 / g, pore volume 0.25 cm³ 3 / g, possessing excellent water vapor adsorption performance and superior water adsorption cycle stability, can efficiently collect water from the air to solve the problem of drinking water shortage in arid areas.

[0028] Example 1: 85 mg of copper chloride dihydrate, 190.5 mg of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 198 mg of 1,3-bis(4-pyridyl)propane (bpp) were mixed in 50 mL of pure water and stirred and refluxed at 50 °C for 8 h. After the reaction was completed, the mixture was washed with methanol and dried to obtain the metal-organic framework material NJU-Bai5.

[0029] Example 2: 511.5 mg of copper chloride dihydrate, 381 mg of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 397 mg of 1,3-bis(4-pyridyl)propane (bpp) were mixed in 50 mL of pure water and stirred under reflux at 80 °C for 12 h. After the reaction was completed, the mixture was washed with methanol and dried to obtain the metal-organic framework material NJU-Bai5.

[0030] Example 3: 170.5 mg of copper chloride dihydrate, 381 mg of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 595.5 mg of 1,3-bis(4-pyridyl)propane (bpp) were mixed in 25 mL of pure water and stirred under reflux at 100 °C for 12 h. After the reaction was completed, the mixture was washed with methanol and dried to obtain the metal-organic framework material NJU-Bai5.

[0031] Example 4: 682 mg of copper chloride dihydrate, 381 mg of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 198.5 mg of 1,3-bis(4-pyridyl)propane (bpp) were mixed in 75 mL of pure water and stirred under reflux at 60 °C for 10 h. After the reaction was completed, the mixture was washed with methanol and dried to obtain the metal-organic framework material NJU-Bai5.

[0032] Example 5: 85 mg of copper chloride dihydrate, 190.5 mg of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 198.5 mg of 1,3-bis(4-pyridyl)propane (bpp) were mixed in 12.5 mL of pure water and stirred under reflux at 60 °C for 5 h. After the reaction was completed, the mixture was washed with methanol and dried to obtain the metal-organic framework material NJU-Bai5.

[0033] Example 6: 170 mg of copper chloride dihydrate, 190.5 mg of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 396 mg of 1,3-bis(4-pyridyl)propane (bpp) were mixed in 25 mL of pure water and reacted hydrothermally at 60 °C for 2 h. After the reaction was completed, the mixture was washed with methanol and dried to obtain the metal-organic framework material NJU-Bai5.

[0034] Example 7: The preparation method is the same as in Example 1, except that 510 mg of copper chloride dihydrate, 190.5 mg of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 198 mg of 1,3-bis(4-pyridyl)propane (bpp) were mixed in 12.5 mL of pure water and reacted hydrothermally at 80 °C for 20 h. After the reaction was completed, the mixture was washed with methanol and dried to obtain the metal-organic framework material NJU-Bai5.

[0035] Example 8: 85 mg of copper chloride dihydrate, 190.5 mg of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 198 mg of 1,3-bis(4-pyridyl)propane (bpp) were mixed in 12.5 mL of pure water and reacted hydrothermally at 60 °C for 5 h. After the reaction was completed, the mixture was washed with methanol and dried to obtain the metal-organic framework material NJU-Bai5.

[0036] Comparative example: 682 mg of copper chloride dihydrate, 381 mg of N,N',N”-tris(carboxymethyl)-1,3,5-benzenetricarboxamide (TCMBT) and 198 mg of 1,3-bis(4-pyridyl)propane (bpp) were mixed in 10 mL of pure water and stirred under reflux at 30 °C for 24 h. After the reaction was completed, the mixture was washed with methanol and dried to obtain the metal-organic framework material NJU-Bai5.

[0037] The metal-organic framework material NJU-Bai5 obtained in some embodiments is selected as an example for demonstration and characterization, wherein... Figure 2 The nitrogen adsorption plot and BET linear region plot at 77K are shown below. Figure 2As can be seen from the preparation methods represented by Examples 5 and 8, NJU-Bai5 obtained has a microporous structure and exhibits a more obvious type I adsorption curve compared to the comparative examples. Figure 3 Images of NJU-Bai5 products prepared by hydrothermal method (a) and stirred reflux method (b), respectively. Figure 4 The characterization results are shown in Figure a, where a is the PXRD pattern, b is the 77 K nitrogen isothermal adsorption curve, and c is the SEM image. As can be seen from the figures, all characteristic peaks in the PXRD patterns of NJU-Bai5 prepared by the hydrothermal method and the stirred reflux method perfectly match the characteristic peaks of the single-crystal structure simulation. Therefore, NJU-Bai5 obtained by both methods possesses high phase purity and crystalline state. Furthermore, NJU-Bai5 obtained by both methods exhibits identical 77 K nitrogen adsorption behavior, namely, typical type I microporous adsorption curves and the same saturated nitrogen adsorption capacity. In summary, there is no significant difference in the crystal structure and nitrogen adsorption performance of the products obtained by the two methods. The most obvious difference between the two lies in their morphology and size. As can be seen from c, the NJU-Bai5 crystals obtained by the hydrothermal method (Example 8) have clearer and more distinct edges, with an average particle size of about 10 μm. In contrast, the NJU-Bai5 crystals obtained by the stirring and reflux method (Example 5) have blunter edges and a smaller average particle size of about 400 nm.

[0038] Experimental Example 1: Water Adsorption Performance Test

[0039] 30 mg of samples prepared in Examples 5 and 8 were replaced with ultra-dry methanol, with the methanol being replaced every 8 hours for three consecutive days. After three days of continuous replacement, the samples were degassed at 120°C for 12 hours to obtain activated samples. The water adsorption performance of the activated samples was tested at 298 K, with five cycles of the test. The test results are as follows: Figure 5 As shown in a and c: NJU-Bai5 obtained according to the preparation method provided by the present invention has a better adsorption curve after 5 cycles, that is, a water adsorption jump is achieved when the relative humidity is as low as 20~35%.

[0040] Experimental Example 2: Water Adsorption Cycle Test

[0041] 30 mg of samples prepared in Examples 7 and 10 were taken respectively, and the same pretreatment steps as in Example 1 were performed. The activated samples were then subjected to a two-point water adsorption cycle test (40% RH adsorption and 20% RH desorption). The results are as follows: Figure 5 As shown in b and d: NJU-Bai5 obtained by the method of the present invention has good water adsorption cycle stability. Even after 20 cycles, it still has good adsorption stability. Therefore, this material can be applied to the field of air water collection.

[0042] The present invention has been disclosed above with reference to preferred embodiments, but it is not intended to limit the present invention. All technical solutions obtained by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the present invention.

Claims

1. A Cu-based metal-organic framework material NJU-Bai5, characterized in that: The metal organic framework material NJU-Bai5 is a one-dimensional channel columnar layer type metal organic framework material formed by coordination self-assembly of a tetranuclear copper cluster and organic ligands N,N',N"-tris(carboxymethyl)-1,3,5-benzene triformamide TCMBT and 1,3-bis(4-pyridyl)propane bpp. 2.A method for preparing Cu-based metal-organic framework material NJU-Bai5, characterized in that The method comprises the following steps: mixing a copper salt, N,N',N"-tris(carboxymethyl)-1,3,5-benzene triformamide TCMBT and 1,3-bis(4-pyridyl)propane bpp in pure water, and preparing by a hydrothermal method or a reflux stirring method, and after the reaction is completed, washing and drying to obtain the metal organic framework material NJU-Bai5. 3.The method for preparing Cu-based metal-organic framework material NJU-Bai5 according to claim 2, characterized in that: The ratio of N,N',N"-tris(carboxymethyl)-1,3,5-benzene triformamide TCMBT to pure water is 1 mmol:(10-150)mL. 4.The method for preparing Cu-based metal-organic framework material NJU-Bai5 according to claim 2, characterized in that: The molar ratio of N,N',N"-tris(carboxymethyl)-1,3,5-benzene triformamide TCMBT to 1,3-bis(4-pyridyl)propane bpp is 1:1-1:

4. 5.The method for preparing Cu-based metal-organic framework material NJU-Bai5 according to claim 2, characterized in that: The molar ratio of N,N',N"-tris(carboxymethyl)-1,3,5-benzene triformamide TCMBT to the copper salt is 1:1-1:

4. 6.The method for preparing Cu-based metal-organic framework material NJU-Bai5 according to claim 2, characterized in that: The treatment temperature of the hydrothermal method or the reflux stirring method is 50-100 DEG C, and the treatment time is 2-12 h.

7. Application of the Cu-based metal organic framework material NJU-Bai5 of claim 1, or the Cu-based metal organic framework material NJU-Bai5 obtained by the preparation method of any one of claims 2-5 in air water collection.

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