Cu-based metal organic framework material NJU-Bai5 as well as preparation method and application thereof

Abstract

The invention provides a Cu-based metal organic framework material NJU-Bai5, and the Cu-based metal organic framework material NJU-Bai5 is a column layer type metal organic framework material which is formed by coordination self-assembly of a tetranuclear copper cluster, an organic ligand N, N ', N' '-tri (carboxymethyl)-1, 3, 5-benzenetriformamide TCMBT and 1, 3-bis (4-pyridyl) propane bpp and has a one-dimensional pore channel. Pure water is adopted as a solvent in the preparation process, other organic solvents are not used, and environmental pollution is reduced; a hydrothermal stirring reflux method which is more suitable for industrial production is adopted, so that the MOF becomes a potential MOF for industrial batch 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 organic framework material has excellent water stability, has good water adsorption capacity in an interval with low relative humidity of 20-30%, can be used for efficiently collecting water in air, and is a potential material for realizing industrial application and production.

Description

Technical Field

[0001] The invention belongs to the research field of porous adsorption materials, and specifically relates to a Cu-based metal organic framework material NJU-Bai5, a preparation method and application thereof. Background Art

[0002] Metal-Organic Frameworks (MOFs) are crystalline materials with permanent pores formed by metal clusters and organic ligands connected by coordination interactions. Based on the multiple coordination capabilities of metal clusters and the substitution of organic ligands by different substituents and different connection methods, the structure is diverse. Since MOFs can adsorb different gases or organic molecules in their pores, they have shown broad application prospects in the fields of gas storage and separation, photocatalysis, drug delivery, and air water collection.

[0003] At present, the vast majority of MOFs are prepared by solvothermal synthesis, and the solvents commonly used to synthesize MOFs, such as N,N-dimethylformamide (DMF), N,N-diethylformamide (DEF) and dimethyl sulfoxide (DMSO), are inherently toxic and flammable. In addition, factors such as high temperature, high pressure, and long reaction time involved in the synthesis are also the main obstacles limiting the large-scale application of MOFs. Summary of the invention

[0004] In order to solve the above-mentioned defects and shortcomings in the prior art, the present invention provides a Cu-based metal organic framework material NJU-Bai5, a preparation method and an application thereof, and prepares a copper-based MOF material NJU-Bai5 with high water stability in a pure water solvent under a relatively low temperature environment.

[0005] To solve the above technical problems: The first object of the present invention is to provide a Cu-based metal organic framework material NJU-Bai5, which is a columnar metal organic framework material with one-dimensional pores formed by coordination self-assembly of a tetranuclear copper cluster and an organic ligand N, N', N"-tris(carboxymethyl)-1,3,5-benzenetricarboxamide TCMBT and 1,3-bis(4-pyridyl)propane bpp. The material has a specific surface area of ​​764 m 2 / g, pore volume 0.25 cm 3 / g, has good water vapor adsorption performance and excellent water adsorption cycle stability, and can be used for efficient air water collection to solve the problem of drinking water shortage in arid areas.

[0006] The second purpose of the present 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 with a hydrothermal method or a reflux stirring method, and washing and drying after the reaction to obtain the metal organic framework material NJU-Bai5.

[0007] Furthermore, copper salts include copper nitrate, copper chloride, copper sulfate and copper acetate.

[0008] Furthermore, the ratio of N, N', N"-tris(carboxymethyl)-1,3,5-benzenetricarboxamide TCMBT and pure water is 1 mmol: (10~150) mL.

[0009] Furthermore, the molar ratio of N,N',N"-tris(carboxymethyl)-1,3,5-benzenetricarboxamide TCMBT and 1,3-bis(4-pyridyl)propane bpp is 1:1-1:4.

[0010] Furthermore, the molar ratio of N,N',N"-tris(carboxymethyl)-1,3,5-benzenetricarboxamide TCMBT and copper salt is 1:1 to 1:4.

[0011] Furthermore, the treatment temperature of the hydrothermal method or the reflux stirring method is 50°C~100°C, and the treatment time is 2~12h.

[0012] The third object of the present 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-mentioned preparation method in air water collection.

[0013] Beneficial technical effects achieved by the present invention: (1) The present invention uses pure water as solvent and does not use other organic solvents, thereby reducing environmental pollution; (2) The present invention adopts a hydrothermal stirring reflux method that is more suitable for industrial production, making it a potential MOF suitable for industrial batch application production; (3) The synthesis temperature selected in the stirring reflux preparation of the present invention can be as low as 30°C. The low reaction temperature not only reduces the reaction energy consumption but also improves the reaction safety performance; (4) The synthesis time required by the present invention can be reduced to 2 hours, thereby improving production efficiency; (5) This metal-organic framework material has excellent water stability and good water adsorption capacity in the relative humidity range of 20-30%. It can efficiently collect water from the air and is a potential material for industrial-level application production. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the ligand and crystal structure of NJU-Bai5 of the present invention; Figure 2 It is the nitrogen adsorption diagram and BET linear region diagram of NJU-Bai5 of the present invention at 77K, wherein a is the nitrogen adsorption diagram at 77K, and b is the BET linear region diagram; Figure 3 Schematic diagram of two synthesis methods of NJU-Bai5 of the present invention; Figure 4 The characterization results of the embodiments of the invention are shown in Figure 1, wherein a is a PXRD pattern, b is a 77 K nitrogen adsorption pattern, and c is a SEM image; Figure 5 5-cycle water adsorption isotherm diagram and 20-cycle two-point water adsorption cycle diagram of Examples 5 and 8 of the present invention at 298K, wherein a and b are 5-cycle water adsorption isotherm diagram and 20-cycle two-point water adsorption cycle diagram of Example 8 at 298K, respectively, and c and d are 5-cycle water adsorption isotherm diagram and 20-cycle two-point water adsorption cycle diagram of Example 5 at 298K, respectively. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with specific examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention.

[0016] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0017] The present invention provides a Cu-based metal organic framework material NJU-Bai5, wherein the metal organic framework material NJU-Bai5 is a columnar metal organic framework material with one-dimensional pores formed by coordination self-assembly of a tetranuclear copper cluster and an organic ligand N,N',N"-tris(carboxymethyl)-1,3,5-benzenetricarboxamide TCMBT and 1,3-bis(4-pyridyl)propane bpp, and the structural schematic diagram is shown in FIG. Figure 1 As shown. Four copper atoms form Figure 1 The tetranuclear copper cluster {[Cu4( µ 3-OH)2] 6+}, each quad-core copper cluster is connected to three Figure 1 The TCMBT ligand shown in c is connected to form Figure 1 The two-dimensional layered network shown in d is then combined with Figure 1 The bpp ligands shown in b in the figure are connected to each other. The bpp ligands act as connecting columns to connect adjacent layered networks to form a columnar three-dimensional network structure with two one-dimensional channels of 3 ~ 6 Å and 3 ~ 4.5 Å, as shown in Figure 2. Figure 1As 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 ​​the material is calculated to be 764 m based on the nitrogen adsorption test curve at 77 K. 2 / g, pore volume 0.25 cm 3 / g, has good water vapor adsorption performance and excellent water adsorption cycle stability, and can be used for efficient air water collection to solve the problem of drinking water shortage in arid areas.

[0018] Example 1: 85 mg of cupric 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, stirred and refluxed at 50°C for 8 h, and after the reaction was completed, washed with methanol and dried to obtain the metal organic framework material NJU-Bai5.

[0019] Example 2: 511.5 mg of cupric 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, stirred and refluxed at 80 °C for 12 h, and after the reaction, washed and dried with methanol to obtain the metal organic framework material NJU-Bai5.

[0020] Example 3: 170.5 mg of cupric 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, stirred and refluxed at 100 °C for 12 h, and after the reaction, washed and dried with methanol to obtain the metal organic framework material NJU-Bai5.

[0021] Example 4: 682 mg of cupric 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, stirred and refluxed at 60 °C for 10 h, and after the reaction, washed with methanol and dried to obtain the metal organic framework material NJU-Bai5.

[0022] 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, stirred and refluxed at 60°C for 5 h, and washed and dried with methanol after the reaction to obtain the metal organic framework material NJU-Bai5.

[0023] Example 6: 170 mg of cupric 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, the metal organic framework material NJU-Bai5 was obtained by washing with methanol and drying.

[0024] Example 7: The preparation method is the same as that of Example 1, except that 510 mg of cupric 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) are mixed in 12.5 mL of pure water, and the mixture is hydrothermally reacted at 80°C for 20 h. After the reaction, the mixture is washed and dried with methanol to obtain the metal organic framework material NJU-Bai5.

[0025] Example 8: 85 mg of cupric 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, the mixture was washed and dried with methanol to obtain the metal organic framework material NJU-Bai5.

[0026] Comparative example: 682 mg of cupric 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, stirred and refluxed at 30°C for 24 hours, and after the reaction, washed and dried with methanol to obtain the metal organic framework material NJU-Bai5.

[0027] The metal organic framework material NJU-Bai5 obtained in some examples was selected as an exemplary display and characterized, wherein: Figure 2 The nitrogen adsorption diagram and BET linear region diagram at 77K are shown in Figure 2. Figure 2 It can be seen that the NJU-Bai5 obtained by the preparation methods represented by Examples 5 and 8 is a microporous structure and has a more obvious type I adsorption curve than the comparative example; Figure 3 These are pictures of NJU-Bai5 products prepared by the hydrothermal method (a) and the stirring reflux method (b). Figure 4Characterization results, where a is an X-ray diffraction pattern (PXRD), b is a 77 K nitrogen isothermal adsorption curve, and c is a SEM photo. It can be seen from the figure that all characteristic peaks of the PXRD spectrum of NJU-Bai5 prepared by the hydrothermal method and the stirring reflux method can completely match the characteristic peaks of the single crystal structure simulation, so the NJU-Bai5 obtained by the two methods has high phase purity and crystalline state. At the same time, the NJU-Bai5 obtained by the two methods exhibits exactly the same 77 K nitrogen adsorption behavior, that is, both are typical adsorption curves of type I micropore characteristics and the same saturated nitrogen adsorption amount. In summary, there is no obvious difference in the crystal structure and nitrogen adsorption performance of the products obtained by the two methods. The more obvious difference between the two lies in the morphology and size. It can be seen from c that the crystal edges of NJU-Bai5 obtained by the hydrothermal method, i.e., Example 8, are clearer and the average particle size is about 10 um, while the crystal edges of NJU-Bai5 obtained by the stirring reflux method, i.e., Example 5, are blunter and the average particle size is smaller, about 400 nm.

[0028] Test Example 1 Water adsorption performance test 30 mg of the samples prepared in Example 5 and Example 8 were respectively replaced with ultra-dry methanol, and the ultra-dry methanol was replaced every 8 hours. After continuous replacement for three days, 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 298K, and the test was repeated 5 times. The test results are shown in FIG. 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%.

[0029] Test Example 2 Water adsorption cycle test 30 mg of the samples prepared in Example 7 and Example 10 were taken respectively, and the same pretreatment steps as in Experimental Example 1 were followed. The activated samples were subjected to a two-point water adsorption cycle test (40% RH adsorption and 20% RH desorption). The results are shown in FIG. Figure 5 As shown in b and d: NJU-Bai5 obtained by the method of the present invention has good water adsorption cycle stability, and still has good adsorption stability even after 20 cycles, so the material can be applied to the field of air water collection.

[0030] The present invention has been disclosed above with preferred embodiments, but they are not intended to limit the present invention. Any technical solutions obtained by adopting equivalent replacement or equivalent transformation solutions 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 columnar metal organic framework material with one-dimensional pores 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.

2. A method for preparing a Cu-based metal organic framework material NJU-Bai5, characterized in that The method comprises 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, adopting a hydrothermal method or a reflux stirring method for preparation, and washing and drying after the reaction to obtain the metal organic framework material NJU-Bai5.

3. The method for preparing the 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-benzenetricarboxamide TCMBT and pure water is 1 mmol: (10~150) mL.

4. The method for preparing the 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-benzenetricarboxamide TCMBT and 1,3-bis(4-pyridyl)propane bpp is 1:1~1:

4.

5. The method for preparing the 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-benzenetricarboxamide TCMBT and copper salt is 1:1-1:

4.

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

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

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