A cobalt metal-organic framework material, its preparation method and application

Abstract

The present invention discloses a cobalt metal-organic framework material, its preparation method and application, belonging to the technical field of metal-organic framework material photocatalysts. The chemical formula of the cobalt metal-organic framework material is [Co(L)(bibp)] n ; wherein L is 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, bibp is 4,4'-bis(imidazolyl)biphenyl, n represents the degree of polymerization and takes positive integers. The cobalt metal-organic framework material belongs to the orthorhombic crystal system and the Fddd space group. By adopting the above-mentioned cobalt metal-organic framework material, its preparation method and application, the cobalt metal-organic framework material can be used as a photocatalyst, has good photocatalytic performance, and can be used as a potential photocatalyst to catalytically degrade antibiotic pollutants in water.

Description

Technical Field

[0001] The present invention relates to the technical field of metal-organic framework photocatalysts, and in particular to a cobalt metal-organic framework material, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of industry worldwide, high-concentration dye wastewater discharged without reaching the standards in industries such as pharmaceuticals and printing has become one of the main sources of water pollution. Due to the relatively stable structure of dyes and the continuous increase in emissions, the treatment of dye wastewater has always been a huge challenge for humanity. Currently, technologies including adsorption, separation, chemical oxidation, flocculation, photocatalytic degradation, etc. are used for the effective removal of dyes in wastewater, but there are defects such as complex and cumbersome pretreatment and high costs. As an emerging technology that has developed rapidly in recent years, photocatalytic degradation has received extensive attention worldwide for removing pollutants in wastewater because it can utilize sustainable and inexhaustible solar energy and can promote reactions under mild conditions. Semiconductor photocatalysts can be directly driven by light and are considered an ideal technology for treating environmental pollution.

[0003] Metal-organic complex materials (CPs) have potential application prospects in many fields such as heterogeneous catalysis, gas storage and separation, and sensing detection due to their significant advantages such as large specific surface area, high stability, and easy modification of structure and properties. In recent years, studies have shown that some CPs exhibit good semiconductor properties under ultraviolet or visible light irradiation. Compared with traditional inorganic semiconductors, CPs have the following significant advantages: open metal active sites, unsaturated metal coordination centers, and adjustable optoelectronic properties of organic linkers, indicating that CPs can be used as photocatalysts for photocatalytic degradation of dye wastewater. Summary of the Invention

[0004] The purpose of the present invention is to provide a cobalt metal-organic framework material, a preparation method thereof, and an application thereof. The cobalt metal-organic framework material can be used as a photocatalyst, has good photocatalytic performance, and can be used as a potential photocatalyst to catalytically degrade antibiotic pollutants in water.

[0005] To achieve the above purpose, the present invention provides a cobalt metal-organic framework material, and the chemical formula of the cobalt metal-organic framework material is [Co(L)(bibp)] n ;

[0006] where L is 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, bibp is 4,4'-bis(imidazolyl)biphenyl, n represents the degree of polymerization and takes a positive integer, and the cobalt metal-organic framework material belongs to the orthorhombic crystal system and the Fddd space group.

[0007] Preferably, the basic structural unit of the cobalt metal-organic framework material includes 1 metal Co2+ , one coordinated 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, and one 4,4'-bis(imidazolyl)biphenyl; 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid coordinates with metal Co through the carboxylate groups at both ends in monodentate and bidentate coordination modes 2+ , and 4,4'-bis(imidazolyl)biphenyl coordinates with metal Co 2+ in a monodentate bridging coordination mode.

[0008] Preferably, one Co 2+ , denoted as Co1, forms a pentacoordinate distorted trigonal bipyramidal configuration with three coordinated oxygen atoms O1, O3, and O4 of two 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acids and two coordinated nitrogen atoms N1 and N2 of one 4,4'-bis(imidazolyl)biphenyl; O4, N1, and N2 occupy the vertices of the triangular face of the distorted trigonal bipyramid, and O1 and O3 occupy the two vertex positions of the distorted trigonal bipyramid; in the distorted trigonal bipyramidal configuration, the bond length of Co-O is 1.9700~2.4183 Å, the bond length of Co-N is 2.0226 Å, the bond angle of O-Co-O is 56.590~138.376º, and the bond angle of O-Co-N is 92.198~125.005º.

[0009] Preferably, adjacent metal Co 2+ is connected through 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid and 4,4'-bis(imidazolyl)biphenyl ligands to form a 2D chain structure, and the 2D chain structure is extended into a three-dimensional network structure through bridging ligands.

[0010] The present invention provides a preparation method of a cobalt metal-organic framework material, comprising the following steps:

[0011] S1. Co-dissolve 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, 4,4'-bis(imidazolyl)biphenyl, and Co(NO3)2·4H2O in deionized water and acetonitrile, and seal and stir at room temperature;

[0012] S2. Add NaOH to adjust the pH and continue stirring;

[0013] S3. Transfer the obtained suspension to a polytetrafluoroethylene reactor, cover the inner lid and place it in a high-pressure resistant stainless steel autoclave, and heat and incubate the high-pressure autoclave using a programmable temperature oven;

[0014] S4. Cool the reaction solution to room temperature at a rate of 3-7 °C·h -1 , and the cobalt metal-organic framework material is obtained.

[0015] Preferably, the molar ratio of 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, 4,4'-bis(imidazolyl)biphenyl and Co(NO3)2·4H2O in S1 is 1:0.5:1 - 1:3:4.

[0016] Preferably, the sealing and stirring time at room temperature in S1 is 25 - 35 min.

[0017] Preferably, the adjusted pH in S2 is 5 - 7, and the stirring time is 25 - 35 min.

[0018] Preferably, the temperature of the autoclave in S3 is 150 - 200 °C, and the incubation time is 36 - 72 h.

[0019] The present invention provides an application of a cobalt metal-organic framework material, applying the above-mentioned cobalt metal-organic framework material to photocatalytic degradation of antibiotic pollutants in water.

[0020] Therefore, the present invention adopts the above-mentioned cobalt metal-organic framework material, its preparation method and application, and has the following beneficial effects:

[0021] (1) The cobalt metal-organic framework material prepared by the present invention can maintain stability within 410 °C.

[0022] (2) The cobalt metal-organic framework material prepared by the present invention can be used as a photocatalyst for the degradation of antibiotic pollutants in water. Among them, under ultraviolet light irradiation, the photocatalytic degradation rate of dimetridazole (DTZ) is 93.5% within 20 min, the photocatalytic degradation rate of nitrofurantoin (NFT) is 81.5%, and the photocatalytic degradation rate of ornidazole (ODZ) is 85.8%.

[0023] (3) The photocatalyst of the cobalt metal-organic framework material prepared by the present invention has a high reuse rate for the degradation of antibiotics.

[0024] The technical solutions of the present invention will be further described in detail below through the drawings and examples. Description of the Drawings

[0025] Figure 1 is the coordination environment diagram of the cobalt metal-organic framework material in the embodiment of the cobalt metal-organic framework material, its preparation method and application of the present invention;

[0026] Figure 2 is the 3D network structure of the cobalt metal-organic framework material in the embodiment of the cobalt metal-organic framework material, its preparation method and application of the present invention;

[0027] Figure 3 is the thermogravimetric analysis diagram of the cobalt metal-organic framework material in the embodiment 1 of the cobalt metal-organic framework material, its preparation method and application of the present invention;

[0028] Figure 4 It is the X-ray powder diffraction pattern of experimental tests and computer simulations in Example 1 of a cobalt metal-organic framework material, its preparation method and application of the present invention;

[0029] Figure 5 It is the infrared spectrum of Example 1 of a cobalt metal-organic framework material, its preparation method and application of the present invention;

[0030] Figure 6 It is the ultraviolet spectrum of photocatalytic degradation of ornidazole (ODZ) in Example 1 of a cobalt metal-organic framework material, its preparation method and application of the present invention;

[0031] Figure 7 It is the ultraviolet spectrum of photocatalytic degradation of nitrofurantoin (NFT) in Example 1 of a cobalt metal-organic framework material, its preparation method and application of the present invention;

[0032] Figure 8 It is the ultraviolet spectrum of photocatalytic degradation of dimetridazole (TDZ) in Example 1 of a cobalt metal-organic framework material, its preparation method and application of the present invention;

[0033] Figure 9 It is the bar graph of the catalytic degradation rates of different antibiotics (ODZ, NFT, TDZ) in Example 1 of a cobalt metal-organic framework material, its preparation method and application of the present invention;

[0034] Figure 10 It is the graph of the change of the catalytic degradation rates of different antibiotics (ODZ, NFT, TDZ) over time in Example 1 of a cobalt metal-organic framework material, its preparation method and application of the present invention;

[0035] Figure 11 It is the comparison graph of the catalytic degradation of dimetridazole (TDZ) with different scavengers (TBA, BQ and AO) in Example 1 of a cobalt metal-organic framework material, its preparation method and application of the present invention;

[0036] Figure 12 It is the graph of the kinetic test results of the catalytic degradation of dimetridazole (TDZ) with different scavengers (TBA, BQ and AO) in Example 1 of a cobalt metal-organic framework material, its preparation method and application of the present invention;

[0037] Figure 13 It is the graph of the reuse test results of the catalytic degradation of dimetridazole (TDZ) in Example 1 of a cobalt metal-organic framework material, its preparation method and application of the present invention. Detailed implementation mode

[0038] The technical solution of the present invention will be further described below with reference to the drawings and examples.

[0039] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present invention pertains.

[0040] Examples

[0041] The present invention provides a cobalt metal-organic framework material, and the chemical formula of the cobalt metal-organic framework material is [Co(L)(bibp)] n ;

[0042] wherein L is 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, bibp is 4,4'-bis(imidazolyl)biphenyl, n represents the degree of polymerization and takes a positive integer, and the cobalt metal-organic framework material belongs to the orthorhombic crystal system and the Fddd space group.

[0043] 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid contains multiple potential coordination sites, including carboxyl groups and oxygen atoms on the benzene ring. These coordination sites can form stable coordination bonds with metal ions, which helps to construct a complex three-dimensional network structure. Due to its relatively large molecular weight and strong rigidity, this ligand can provide additional spatial support, thereby enhancing the mechanical stability and thermal stability of the entire structure.

[0044] 4,4'-bis(imidazolyl)biphenyl contains two imidazole rings, and each imidazole ring can form coordination bonds with one or more metal ions, which enables it to effectively connect metal centers and construct complex two-dimensional or three-dimensional network structures. The rigidity and aromaticity of the imidazole rings help to improve the overall stability of the material. In addition, the coordination bonds formed by the nitrogen atoms in the imidazole rings with metal ions are very stable, thereby enhancing the thermal stability and chemical stability of the entire framework.

[0045] The basic structural unit of the cobalt metal-organic framework material includes 1 metal Co 2+ , 1 coordinated 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, and 1 4,4'-bis(imidazolyl)biphenyl; 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid adopts monodentate and bidentate coordination modes through the carboxylate groups at both ends to coordinate with metal Co 2+ coordinate; 4,4'-bis(imidazolyl)biphenyl is monodentate bridged coordinated with metal Co 2+ coordinate.

[0046] 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid combines with Co 2+ through monodentate and bidentate coordination modes, providing flexibility and diversity, which helps to form complex structures. Through bidentate coordination, this ligand can more firmly fix the metal center, thereby enhancing the mechanical stability and thermal stability of the entire framework. 4,4'-bis(imidazolyl)biphenyl is monodentate coordinated with Co 2+Connection forms a bridging structure, which helps to construct a two-dimensional or three-dimensional network. The coordination bond formed between the nitrogen atom in the imidazole ring and the metal ion is very stable, enhancing the thermal stability and chemical stability of the entire framework.

[0047] 1 Co 2+ Denoted as Co1, it forms a five-coordinate distorted trigonal bipyramidal configuration with three coordinating oxygen atoms O1, O3, and O4 of 2 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acids, and two coordinating nitrogen atoms N1 and N2 of 1 4,4'-bis(imidazolyl)biphenyl; O4, N1, and N2 occupy the vertices of the triangular face of the distorted trigonal bipyramid; O1 and O3 occupy the two vertex positions of the distorted trigonal bipyramid; in the distorted trigonal bipyramidal configuration, the bond length of Co-O is 1.9700 - 2.4183 Å, the bond length of Co-N is 2.0226 Å, the bond angle of O-Co-O is 56.590 - 138.376º, and the bond angle of O-Co-N is 92.198 - 125.005º.

[0048] Adjacent metal Co 2+ Connects through 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid and 4,4'-bis(imidazolyl)biphenyl ligands to form a 2D chain structure, and the 2D chain structure is extended to a three-dimensional network structure through bridging ligands.

[0049] In this three-dimensional network structure, each Co 2+ Is connected to different ligands through multiple coordination bonds to form a strong and stable network, enabling the cobalt metal-organic framework material to maintain good stability under various conditions. The 2D chain structure usually provides a very large specific surface area, which is particularly beneficial for adsorption applications.

[0050] The present invention provides a preparation method of a cobalt metal-organic framework material, comprising the following steps:

[0051] S1. Co-dissolve 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, 4,4'-bis(imidazolyl)biphenyl, and Co(NO3)2·4H2O in deionized water and acetonitrile at a molar ratio of 1:0.5:1 - 1:3:4, and seal and stir at room temperature for 25 - 35 min;

[0052] S2. Add NaOH to adjust the pH to 5 - 7, and continue stirring for 25 - 35 min;

[0053] S3. Transfer the obtained suspension to a polytetrafluoroethylene reactor, cover the inner lid and place it in a high-pressure-resistant stainless steel autoclave, and heat the autoclave to 150 - 200 °C with a programmable temperature oven and incubate for 36 - 72 h;

[0054] S4. Cool the reaction solution at 3 - 7 °C·h -1Cool it to room temperature at a rate of, and then the cobalt metal-organic framework material is obtained.

[0055] Example 1

[0056] A cobalt metal-organic framework material with the chemical formula [Co(L)(bibp)] n , which is prepared through the following steps:

[0057] Mix 0.01 mol of 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid L, 0.015 mol of 4,4'-bis(imidazolyl)biphenyl, 0.02 mol of Co(NO3)2·4H2O with 5 mL of deionized water and 5 mL of acetonitrile uniformly, seal and stir at room temperature for 30 min, adjust the pH = 5 with 0.5 mol / L NaOH, and then stir for another 30 min. Transfer the obtained suspension to a polytetrafluoroethylene reactor (25 mL), cover the inner lid and place it in a high-pressure resistant stainless steel autoclave. Heat the autoclave to 160 °C with a programmable temperature oven and incubate for 72 hours. Then cool the reaction solution to room temperature at a rate of 5 °C·h -1 , and the cobalt metal-organic framework material is obtained.

[0058] Example 2

[0059] A cobalt metal-organic framework material with the chemical formula [Co(L)(bibp)] n , which is prepared through the following steps:

[0060] Mix 0.02 mol of 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid L, 0.03 mol of 4,4'-bis(imidazolyl)biphenyl, 0.04 mol of Co(NO3)2·4H2O with 10 mL of deionized water and 10 mL of acetonitrile uniformly, seal and stir at room temperature for 30 min, adjust the pH = 6 with 0.5 mol / L NaOH, and then stir for another 30 min. Transfer the obtained suspension to a polytetrafluoroethylene reactor (25 mL), cover the inner lid and place it in a high-pressure resistant stainless steel autoclave. Heat the autoclave to 160 °C with a programmable temperature oven and incubate for 72 hours. Then cool the reaction solution to room temperature at a rate of 5 °C·h -1 , and the cobalt metal-organic framework material is obtained.

[0061] Example 3

[0062] A cobalt metal-organic framework material with the chemical formula [Co(L)(bibp)] n , which is prepared through the following steps:

[0063] Mix 0.2 mol of 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid L, 0.3 mol of 4,4'-bis(imidazolyl)biphenyl, 0.4 mol of Co(NO3)2·4H2O with 50 mL of deionized water and 50 mL of acetonitrile uniformly, stir them sealed at room temperature for 30 min, adjust the pH to 7 with 0.5 mol / L NaOH, and then stir for another 30 min. Transfer the obtained suspension to a polytetrafluoroethylene reactor (150 mL), cover the inner lid and place it in a high-pressure resistant stainless steel autoclave, heat the autoclave to 160 °C in a programmable temperature oven and incubate for 72 hours. Then cool the reaction solution to room temperature at a rate of 5 °C·h -1 to obtain the cobalt metal-organic framework material.

[0064] Characterize the cobalt metal-organic framework material prepared in Example 1 to obtain the crystallographic parameters shown in Table 1 and the partial bond length and bond angle data shown in Table 2. The theoretical values of elemental analysis of the complex are C: 67.30, H: 3.84, N: 8.26 (from CCDC: 2385555), and the experimental values are C: 67.75, H: 3.63, N: 8.12.

[0065] Table 1 Crystallographic parameters of the complex

[0066]

[0067] *R = ∑(F o – F c ) / ∑(F o ), **wR2 = {∑[w(F o 2 – F c 2 ) 2 / ∑(F o 2 ) 2} 1 / 2 .

[0068] Table 2 Partial bond lengths (Å) and bond angles (°) of the complex

[0069]

[0070] Detect the cobalt metal-organic framework material prepared in Example 1 (the following tests are all based on the cobalt metal-organic framework material of Example 1), and its coordination environment diagram is as shown in Figure 1 . It can be seen from the figure that the cobalt metal-organic framework material has a high specific surface area, rich pore structures inside, and good stability. Its 3D network structure is as shown in Figure 2As shown, the figure shows the three-dimensional network structure of the cobalt metal-organic framework material, clarifying the types and positions of different atoms. This structure has a high specific surface area and porosity, and thus has application value in the fields of gas adsorption, catalysis, separation, etc.

[0071] Thermogravimetric analysis was carried out on the cobalt metal-organic framework material prepared in Example 1. As Figure 3 shown, the thermogravimetric curve is as follows: Thermogravimetric analysis of the cobalt metal-organic framework material sample was carried out under N2 conditions. The cobalt metal-organic framework material has a small weight loss in the range of 92 - 413 °C, which is the weight loss of solvent molecules. When the temperature rises above 413 °C, the organic ligands in the cobalt metal-organic framework material begin to decompose, and the overall framework of the organic ligand molecules in the molecule begins to collapse, and finally decomposes into metal oxides.

[0072] The experimental test and computer simulation X-ray powder diffraction evaluation of the cobalt metal-organic framework material prepared in Example 1 are as Figure 4 shown. By comparing the theoretical simulated powder XRD pattern and the experimental data test pattern of the sample, the results show that in the range of 5 - 50 degrees (2θ), the peak shapes and positions of the theoretical data pattern and the experimental measured pattern are consistent. At the same time, it is consistent with the elemental analysis results of the sample, indicating that the sample of the synthesized complex is a pure phase.

[0073] The infrared spectrum test of the cobalt metal-organic framework material prepared in Example 1 is as Figure 5 shown. The broad absorption peak at 3431 cm -1 is the absorption peak of O-H in the solvent water in the framework material. The absorption peak at 1608 cm -1 is the stretching vibration of the C=O double bond of the carboxylate group in 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid. The absorption peak appearing near 1518 cm -1 is the stretching vibration of the C=N double bond on the 4,4'-bis(imidazolyl)biphenyl ring of the auxiliary ligand. The absorption peaks at 1378 cm -1 and 1245 cm -1 are the symmetric and asymmetric stretching vibrations of the carboxylate group.

[0074] To detect the photocatalytic properties of the cobalt metal-organic framework material prepared in Example 1 and verify whether it can be used as a potential photocatalyst for the catalytic degradation of antibiotics in water, the photocatalytic degradation of antibiotics experiment is as follows: Grind 25 mg of the sample and add it to the aqueous solutions of dimetridazole (TDZ), nitrofurantoin (NFT), and ornidazole (ODZ), and stir to achieve adsorption-desorption equilibrium. Then place the mixed solution under an ultraviolet Hg lamp and stir, and take out 5 mL of the solution every 2 min.

[0075] Aqueous solutions of the antibiotics tinidazole (TDZ), nitrofurantoin (NFT), and ornidazole (ODZ) were selected to explore the photocatalytic activity of cobalt metal-organic framework material samples.

[0076] As Figure 6 , Figure 7 , Figure 8 and Figure 9 shown, through catalytic degradation experiments, it was demonstrated that whether it was ornidazole (ODZ), nitrofurantoin (NFT), or tinidazole (TDZ), when irradiated under ultraviolet light, in the presence of the cobalt metal-organic framework material catalyst, the ultraviolet absorption peaks of the three antibiotics decreased significantly with time, indicating that the catalyst had strong photocatalytic degradation ability for tinidazole (TDZ), nitrofurantoin (NFT), and ornidazole (ODZ), especially TDZ.

[0077] As Figure 9 and Figure 10 shown, according to the calculation of the solution concentration C / C0 (C is the absorption peak intensity at a certain time, and C0 is the absorption peak intensity of the initial concentration), within 20 min, the photocatalytic degradation rate of the cobalt metal-organic framework material for ornidazole (ODZ) was 85.8%; the photocatalytic degradation rate of the cobalt metal-organic framework material for nitrofurantoin (NFT) was 81.5%; the photocatalytic degradation rate of the cobalt metal-organic framework material for tinidazole (TDZ) was 93.5%; the cobalt metal-organic framework material had good photocatalytic degradation effects on the three antibiotics, especially on tinidazole (TDZ).

[0078] The catalytic mechanism of the cobalt metal-organic framework material in tinidazole (TDZ) was tested. The ·OH scavenger tert-butanol (TBA), the photo-generated hole scavenger ammonium oxalate (AO), and the ·O2 - scavenger benzoquinone (BQ) were respectively added to the photocatalytic reaction system.

[0079] As Figure 11 shown, according to the calculation of the solution concentration C / C0 (C is the absorption peak intensity at a certain time, and C0 is the absorption peak intensity of the initial concentration), the degradation rate of tinidazole (TDZ) without adding the three scavengers was 93.5%, the degradation rate of tinidazole (TDZ) under the condition of adding TBA was 87.2%, the degradation rate of tinidazole (TDZ) under the condition of adding AO was 64.6%, and the degradation rate of tinidazole (TDZ) under the condition of adding BQ was 25.5%. Through data comparison in the presence of different scavengers, the photodegradation of tinidazole (TDZ) was jointly dominated by ·O2 - radicals and photo-generated holes.

[0080] As Figure 12As shown, kinetic research tests indicate that with Ln(C0 / C) as the ordinate and reaction time t as the abscissa, the linear coefficients of the obtained function images are as follows: NFT: 0.9826, ODZ: 0.9889, TDZ: 0.9840. This shows that the degradation reactions of the cobalt metal-organic framework material for the 3 antibiotics all conform to the characteristics of the first-order kinetic reaction. The rate constants of the degradation reactions within 20 minutes are 0.0740 min -1 , 0.1015 min -1 , 0.1373 min -1 .

[0081] As Figure 13 shown, a test on the repeated use rate of the catalyst was conducted on the cobalt metal-organic framework material. After the degradation reaction ended, the cobalt metal-organic framework material was centrifuged, washed, and dried, and then used for the next degradation reaction of dimetridazole (TDZ). The experimental results show that after 4 cycles of use, the catalytic activity of the cobalt metal-organic framework material did not degrade significantly, indicating a high repeated use rate of the cobalt metal-organic framework material.

[0082] In summary, for the cobalt metal-organic framework material prepared in the present invention, the photocatalytic degradation rate of ornidazole (ODZ) within 20 min is 85.8%; the photocatalytic degradation rate of nitrofurantoin (NFT) by the cobalt metal-organic framework material is 81.5%; the photocatalytic degradation rate of dimetridazole (TDZ) by the cobalt metal-organic framework material is 93.5%; the cobalt metal-organic framework material has good photocatalytic degradation effects on the 3 antibiotics, especially for dimetridazole (TDZ). The cobalt metal-organic framework material can be used as a potential photocatalyst to catalytically degrade antibiotics in water.

[0083] Therefore, the present invention adopts the above-mentioned cobalt metal-organic framework material and its preparation method and application. This cobalt metal-organic framework material can be used as a photocatalyst, has good photocatalytic performance, and can be used as a potential photocatalyst to catalytically degrade antibiotic pollutants in water.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A cobalt metal organic framework material, characterized in that: The chemical formula of cobalt metal organic framework material is [Co(L)(bibp)] n ; Where L is 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, bibp is 4,4'-bis(imidazolyl)biphenyl, n represents the degree of polymerization, which is a positive integer. The cobalt metal organic framework material belongs to the orthorhombic system and the Fddd space group, and its parameters are α=90°, β=90°, γ=90°, Z=16.

2. A cobalt metal organic framework material according to claim 1, characterized in that: The basic structural unit of cobalt metal organic framework materials consists of a metal Co 2+ , 1 coordinated 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, 1 4,4'-bis(imidazolyl)biphenyl; 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid adopts monodentate and bidentate coordination mode with metal Co through the carboxyl groups at both ends. 2+ Coordination, 4,4'-bis(imidazolyl)biphenyl with metal Co 2+ Monodentate bridging coordination.

3. A cobalt metal organic framework material according to claim 2, characterized in that: 1Co 2+ Denoted as Co1, it forms a five-coordinated deformed trigonal bipyramid configuration with three coordinated oxygen atoms O1, O3 and O4 of two 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acids and two coordinated nitrogen atoms N1 and N2 of one 4,4'-bis(imidazolyl)biphenyl; O4, N1 and N2 occupy the vertices of the triangular face of the deformed trigonal bipyramid, and O1 and O3 occupy the two vertices of the deformed trigonal bipyramid; The bond length of Co-O in the deformed trigonal bipyramidal configuration is The bond length of Co-N is The bond angle of O-Co-O is 56.590~138.376°, and the bond angle of O-Co-N is 92.198~125.005°.

4. A cobalt metal organic framework material according to claim 3, characterized in that: Adjacent metal Co 2+ A 2D chain structure is formed by connecting 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid and 4,4'-bis(imidazolyl)biphenyl ligands, and the 2D chain structure is expanded into a three-dimensional network structure through a bridging ligand.

5. A method for preparing a cobalt metal organic framework material as claimed in claim 4, characterized in that: The following steps are involved: S1. Dissolve 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, 4,4'-bis(imidazolyl)biphenyl and Co(NO3)2·4H2O in deionized water and acetonitrile, and stir in a sealed container at room temperature; S2, add NaOH to adjust pH, continue stirring; S3, transferring the obtained suspension to a polytetrafluoroethylene reactor, covering it with an inner cover and placing it in a high-pressure stainless steel reactor, heating the high-pressure reactor in a programmable temperature-controlled oven and keeping it warm for culturing; S4, the reaction solution was heated at 3-7℃·h -1 The cobalt metal organic framework material is obtained by cooling it to room temperature at a rate of 6. The method for preparing a cobalt metal organic framework material according to claim 5, characterized in that: The molar ratio of 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, 4,4'-bis(imidazolyl)biphenyl and Co(NO3)2·4H2O in S1 is 1:0.5:1-1:3:

4.

7. The method for preparing a cobalt metal organic framework material according to claim 6, characterized in that: The sealed stirring time at room temperature in S1 is 25-35 minutes.

8. The method for preparing a cobalt metal organic framework material according to claim 6, characterized in that: The pH adjusted in S2 is 5-7, and the stirring time is 25-35 min.

9. The method for preparing a cobalt metal organic framework material according to claim 6, characterized in that: The temperature of the high-pressure reactor in S3 is 150-200°C, and the insulation and cultivation time is 36-72h.

10. An application of a cobalt metal organic framework material, characterized in that: The cobalt metal organic framework material described in claim 4 is used for photocatalytic degradation of antibiotic pollutants in water.

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