Cobalt metal organic framework material and preparation method and application thereof

Abstract

The invention discloses a cobalt metal organic framework material and a preparation method and application thereof, and belongs 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-carboxyl phenoxy)-4-bibenzoic acid, bibp is 4, 4'-bis (imidazolyl) biphenyl, n represents the degree of polymerization and is a positive integer, and the cobalt metal organic framework material belongs to an orthorhombic system and an Fddd space group. According to the cobalt metal organic framework material and the preparation method and application thereof, the cobalt metal organic framework material can serve as a photocatalyst, has good photocatalytic performance and can serve as a potential photocatalyst to catalyze and degrade antibiotic pollutants in water.

Description

Technical Field

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

[0002] With the rapid development of industry worldwide, the large amount of high-concentration dye wastewater discharged from industries such as pharmaceuticals and printing that does not meet standards 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 facing mankind. Currently, technologies including adsorption, separation, chemical oxidation, flocculation, and photocatalytic degradation are used to effectively remove dyes from wastewater, but they have disadvantages such as complex and tedious pre-treatment and high costs. As an emerging technology that has developed rapidly in recent years, photocatalytic degradation has received widespread attention worldwide in the removal of pollutants from 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 to be an ideal technology for treating environmental pollution.

[0003] Metal-organic complexes (CPs) have significant advantages, including large surface area, high stability, and easy modification of structure and properties. They have potential applications in various fields, including heterogeneous catalysis, gas storage and separation, and sensing. Recent studies have shown that certain CPs exhibit excellent semiconductor properties under ultraviolet or visible light irradiation. Compared with traditional inorganic semiconductors, CPs possess the following significant advantages: open metal active sites, unsaturated metal coordination centers, and tunable organic linker photoelectric properties. This suggests that CPs can be used as photocatalysts for the 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 and 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 catalyze the degradation of antibiotic pollutants in water.

[0005] To achieve the above object, the present invention provides a cobalt metal organic framework material, 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 is a positive integer. The cobalt metal organic framework material belongs to the orthorhombic crystal system and the Fddd space group.

[0006] Preferably, the basic structural unit of the cobalt metal organic framework material includes 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 and metal Co 2+ Monodentate bridged coordination.

[0007] Preferably, 1 Co 2+ Denoted as Co1, it forms a pentacoordinated distorted trigonal bipyramid with the three coordinated oxygen atoms O1, O3, and O4 of two 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acids and the two coordinated nitrogen atoms N1 and N2 of one 4,4'-bis(imidazolyl)biphenyl. O4, N1, and N2 occupy the triangular vertices of the distorted trigonal bipyramid, and O1 and O3 occupy the two vertices of the distorted trigonal bipyramid. In the distorted trigonal bipyramid, the Co-O bond length is 1.9700~2.4183Å, the Co-N bond length is 2.0226Å, the O-Co-O bond angle is 56.590~138.376º, and the O-Co-N bond angle is 92.198~125.005º.

[0008] Preferably, the 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.

[0009] The present invention provides a method for preparing a cobalt metal organic framework material, comprising the following steps: 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 and 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 incubation; 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 speed of

[0010] 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.

[0011] Preferably, the sealed stirring time at room temperature in S1 is 25-35 minutes.

[0012] Preferably, the pH adjusted in S2 is 5-7, and the stirring time is 25-35 min.

[0013] Preferably, the temperature of the high-pressure reactor in S3 is 150-200° C., and the insulation and incubation time is 36-72 h.

[0014] The present invention provides an application of a cobalt metal organic framework material, wherein the cobalt metal organic framework material described above is applied to photocatalytic degradation of antibiotic pollutants in water.

[0015] Therefore, the present invention adopts the above-mentioned cobalt metal organic framework material and its preparation method and application, which has the following beneficial effects: (1) The cobalt metal organic framework material prepared by the present invention can remain stable within 410°C.

[0016] (2) The cobalt metal organic framework material prepared by the present invention can be used as a photocatalyst to degrade antibiotic pollutants in water. Under ultraviolet light irradiation, the photocatalytic degradation rate of dimetridazole (DTZ) within 20 minutes is 93.5%, the photocatalytic degradation rate of nitrofurantoin (NFT) is 81.5%, and the photocatalytic degradation rate of ornidazole (ODZ) is 85.8%.

[0017] (3) The cobalt metal organic framework material photocatalyst prepared by the present invention has a high reuse rate for degrading antibiotics.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a diagram of the coordination environment of a cobalt metal organic framework material of the present invention, a preparation method thereof, and an application embodiment; Figure 2 The present invention relates to a cobalt metal organic framework material and a preparation method and a cobalt metal organic framework material 3D network structure of an application embodiment thereof; Figure 3 This is a thermogravimetric analysis diagram of a cobalt metal organic framework material according to a cobalt metal organic framework material and a preparation method thereof and application example 1 of the present invention; Figure 4 This is an X-ray powder diffraction pattern of experimental testing and computer simulation of a cobalt metal organic framework material and its preparation method and application example 1 of the present invention; Figure 5 This is an infrared spectrum of a cobalt metal organic framework material and its preparation method and application example 1 of the present invention; Figure 6 The present invention is a cobalt metal organic framework material and its preparation method and application example 1 photocatalytic degradation of ornidazole (ODZ) UV spectrum; Figure 7 The present invention is a cobalt metal organic framework material and its preparation method and application example 1 photocatalytic degradation of nitrofurantoin (NFT) UV spectrum; Figure 8 The present invention is a cobalt metal organic framework material and its preparation method and application example 1 photocatalytic degradation of dimethylnitroimidazole (TDZ) UV spectrum; Figure 9 This is a bar graph showing the catalytic degradation rates of different antibiotics (ODZ, NFT, TDZ) according to Example 1 of a cobalt metal organic framework material and its preparation method and application; Figure 10 This is a graph showing the change in catalytic degradation rate of different antibiotics (ODZ, NFT, TDZ) over time according to Example 1 of a cobalt metal organic framework material and its preparation method and application; Figure 11 This is a comparison chart of the catalytic degradation of dimetridazole (TDZ) by different scavengers (TBA, BQ and AO) using a cobalt metal organic framework material and its preparation method according to the present invention and Application Example 1; Figure 12 This is a graph showing the kinetic test results of the catalytic degradation of dimetridazole (TDZ) by different scavengers (TBA, BQ and AO) according to Example 1 of a cobalt metal organic framework material and its preparation method and application; Figure 13 This is a graph showing the test results of repeated use of a cobalt metal organic framework material and its preparation method and application example 1 of the present invention for catalytic degradation of dimetridazole (TDZ). DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0022] Example The present invention provides a cobalt metal organic framework material, 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 is a positive integer. The cobalt metal organic framework material belongs to the orthorhombic crystal system and the Fddd space group.

[0023] 4'-(4-Carboxyphenoxy)-4-biphenylcarboxylic acid contains multiple potential coordination sites, including the carboxyl group and the oxygen atoms on the benzene ring. These sites can form stable coordination bonds with metal ions, contributing to the construction of complex three-dimensional network structures. Due to its large molecular weight and strong rigidity, this ligand can provide additional steric support, thereby enhancing the mechanical and thermal stability of the entire structure.

[0024] 4,4'-Bis(imidazolyl)biphenyl contains two imidazole rings, each of which can form coordination bonds with one or more metal ions. This allows it to effectively connect metal centers and construct complex two-dimensional or three-dimensional network structures. The rigidity and aromaticity of the imidazole rings contribute to the overall stability of the material. In addition, the nitrogen atoms in the imidazole rings form very stable coordination bonds with the metal ions, thereby enhancing the thermal and chemical stability of the entire framework.

[0025] 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 and metal Co 2+ Monodentate bridged coordination.

[0026] 4'-(4-Carboxyphenoxy)-4-bibenzoic acid binds to Co via monodentate and bidentate coordination modes. 2+ The combination provides flexibility and diversity, which helps to form complex structures. Through bidentate coordination, the ligand can more firmly fix the metal center, thereby improving the mechanical and thermal stability of the entire framework. 4,4'-Bis(imidazolyl)biphenyl binds to Co through monodentate coordination. 2+ The nitrogen atoms in the imidazole ring form very stable coordination bonds with metal ions, which enhances the thermal and chemical stability of the entire framework.

[0027] 1 Co 2+Denoted as Co1, it forms a five-coordinated distorted trigonal bipyramid configuration with the three coordinated oxygen atoms O1, O3 and O4 of two 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acids and the two coordinated nitrogen atoms N1 and N2 of one 4,4'-bis(imidazolyl)biphenyl. O4, N1 and N2 occupy the triangular vertices of the distorted trigonal bipyramid; O1 and O3 occupy the two vertices of the distorted trigonal bipyramid. In the distorted trigonal bipyramid configuration, the Co-O bond length is 1.9700~2.4183Å, the Co-N bond length is 2.0226Å, the O-Co-O bond angle is 56.590~138.376º, and the O-Co-N bond angle is 92.198~125.005º.

[0028] 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.

[0029] In this three-dimensional network structure, each Co 2+ By connecting to different ligands through multiple coordination bonds to form a strong and stable network, cobalt metal-organic frameworks can maintain good stability under various conditions. The 2D chain structure can generally provide a very large specific surface area, which is particularly advantageous for adsorption applications.

[0030] The present invention provides a method for preparing a cobalt metal organic framework material, comprising the following steps: S1. 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 stir in a sealed container at room temperature for 25-35 minutes; S2. Add NaOH to adjust the pH to 5-7 and continue stirring for 25-35 minutes; S3. Transfer the obtained suspension to a polytetrafluoroethylene reactor, cover it with an inner cover and place it in a high-pressure stainless steel reactor. Heat the high-pressure reactor to 150-200° C. in a programmable temperature-controlled oven and incubate at this temperature for 36-72 hours. 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 speed of

[0031] Example 1 A cobalt metal organic framework material, whose chemical formula is [Co(L)(bibp)] n , obtained by the following steps: 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 were mixed evenly with 5 mL of deionized water and 5 mL of acetonitrile, sealed and stirred at room temperature for 30 minutes, adjusted to pH = 5 with 0.5 mol / L NaOH, and stirred for another 30 minutes. The resulting suspension was transferred to a polytetrafluoroethylene reactor (25 mL), covered with an inner lid and placed in a high-pressure stainless steel reactor. The high-pressure reactor was heated to 160°C in a programmable temperature oven and kept warm for 72 hours. The reaction solution was then heated at 5°C·h -1 The reaction mixture was cooled to room temperature at a rate of 100 nm to obtain a cobalt metal organic framework material.

[0032] Example 2 A cobalt metal organic framework material, whose chemical formula is [Co(L)(bibp)] n , obtained by the following steps: 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 were mixed evenly with 10 mL of deionized water and 10 mL of acetonitrile, sealed and stirred at room temperature for 30 min, adjusted to pH = 6 with 0.5 mol / L NaOH, and stirred for another 30 min. The resulting suspension was transferred to a polytetrafluoroethylene reactor (25 mL), covered with an inner lid and placed in a high-pressure stainless steel reactor. The high-pressure reactor was heated to 160°C in a programmable temperature oven and kept warm for 72 hours. The reaction solution was then heated at 5°C·h -1 The reaction mixture was cooled to room temperature at a rate of 100 nm to obtain a cobalt metal organic framework material.

[0033] Example 3 A cobalt metal organic framework material, whose chemical formula is [Co(L)(bibp)] n , obtained by the following steps: 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 were mixed evenly with 50 mL of deionized water and 50 mL of acetonitrile, sealed and stirred at room temperature for 30 minutes, adjusted to pH = 7 with 0.5 mol / L NaOH, and stirred for another 30 minutes. The resulting suspension was transferred to a polytetrafluoroethylene reactor (150 mL), covered with an inner lid and placed in a high-pressure stainless steel reactor. The high-pressure reactor was heated to 160°C in a programmable temperature-controlled oven and kept warm for 72 hours. The reaction solution was then heated at 5°C·h -1 The reaction mixture was cooled to room temperature at a rate of 100 nm to obtain a cobalt metal organic framework material.

[0034] The cobalt metal-organic framework material prepared in Example 1 was characterized to obtain the crystallographic parameters shown in Table 1, and some bond length and bond angle data shown in Table 2. The elemental analysis of the complex showed theoretical values ​​of C: 67.30, H: 3.84, N: 8.26 (derived from CCDC: 2385555), and experimental values ​​of C: 67.75, H: 3.63, N: 8.12.

[0035] Table 1 Crystallographic parameters of the complexes

[0036] *R=∑(F o –F c ) / ∑(F o ), **wR2={∑[w(F o 2 –F c 2 ) 2 ] / ∑(F o 2 ) 2} 1 / 2 .

[0037] Table 2 Some bond lengths (Å) and bond angles (°) of the complexes

[0038] The cobalt metal organic framework material prepared in Example 1 was tested (the following experiments are all based on the cobalt metal organic framework material in Example 1), and its coordination environment is shown in the figure below. Figure 1 As shown in the figure, it can be seen that the cobalt metal organic framework material has a high specific surface area, a rich pore structure inside, and good stability. Its 3D network structure is as follows Figure 2 As shown in the figure, the three-dimensional network structure of the cobalt metal organic framework material is displayed, clarifying the types and positions of different atoms. This structure has high specific surface area and porosity, and therefore has application value in gas adsorption, catalysis, separation and other fields.

[0039] The cobalt metal organic framework material prepared in Example 1 was subjected to thermogravimetric analysis. Figure 3 Thermogravimetric curves are shown below: Thermogravimetric analysis of a cobalt metal-organic framework (COF) sample under nitrogen (N2) conditions reveals a slight weight loss between 92°C and 413°C, attributable to the weight loss of solvent molecules. When the temperature rises above 413°C, the organic ligands within the COF begin to decompose, causing the overall molecular framework to collapse and ultimately decompose into metal oxides.

[0040] The experimental test and computer simulated X-ray powder diffraction evaluation of the cobalt metal organic framework material prepared in Example 1 are as follows Figure 4 As shown in the figure, by comparing the theoretical simulated powder XRD pattern of the sample with the experimental data test pattern, the results show that the peak shape and position of the theoretical data pattern and the experimental measured pattern are consistent in the angle range of 5-50 (2θ). 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.

[0041] The infrared spectrum test of the cobalt metal organic framework material prepared in Example 1 is as follows: Figure 5 As shown, at 3431cm -1 The broad absorption peak at 1608 cm is the absorption peak of OH in the solvent water of the framework material. -1 The absorption peak at 1518 cm is the C=O double bond stretching vibration of the carboxylate in 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid. -1 The absorption peak that appears near is the stretching vibration of the C=N double bond on the auxiliary 4,4'-bis(imidazolyl)biphenyl ring, 1378cm -1 and 1245cm -1 The absorption peaks at are the symmetric and asymmetric stretching vibrations of carboxyl groups.

[0042] The photocatalytic properties of the cobalt metal-organic framework prepared in Example 1 were tested to verify its potential as a photocatalyst for the degradation of antibiotics in water. The following experiment was performed: 25 mg of the sample was finely ground and added to an aqueous solution of dimetridazole (TDZ), nitrofurantoin (NFT), and ornidazole (ODZ), stirring until adsorption-desorption equilibrium was achieved. The mixed solution was then stirred under a UV Hg lamp, with 5 mL of solution removed every 2 minutes.

[0043] Aqueous solutions of antibiotics dimetridazole (TDZ), nitrofurantoin (NFT) and ornidazole (ODZ) were selected to explore the photocatalytic activity of cobalt metal-organic framework material samples.

[0044] like Figure 6 、 Figure 7 、 Figure 8 and Figure 9 As shown in the figure, the catalytic degradation experiment proved that, whether ornidazole (ODZ), nitrofurantoin (NFT) or dimetridazole (TDZ), when irradiated under ultraviolet light, in the presence of cobalt metal organic framework catalyst, the ultraviolet absorption peaks of the three antibiotics significantly weakened with the increase of time, indicating that the catalyst has a strong photocatalytic degradation ability for dimetridazole (TDZ), nitrofurantoin (NFT) and ornidazole (ODZ), especially TDZ.

[0045] like Figure 9 and Figure 10As shown, according to the solution concentration C / C0 calculation (C is the absorption peak intensity at a certain time, C0 is the absorption peak intensity of the initial concentration), within 20 minutes, the photocatalytic degradation rate of ornidazole (ODZ) by cobalt metal organic framework material is 85.8%; the photocatalytic degradation rate of nitrofurantoin (NFT) by cobalt metal organic framework material is 81.5%; the photocatalytic degradation rate of dimetridazole (TDZ) by cobalt metal organic framework material is 93.5%; cobalt metal organic framework material has good photocatalytic degradation effect on the three antibiotics, especially for dimetridazole (TDZ).

[0046] The catalytic mechanism of cobalt metal organic framework materials in dimethylnitroimidazole (TDZ) was tested. Tertiary butyl alcohol (TBA), a scavenger of ·OH, ammonium oxalate (AO), and ·O2 were added to the photocatalytic reaction system. - The capture agent benzoquinone (BQ)

[0047] like Figure 11 As shown, according to the solution concentration C / C0 calculation (C is the absorption peak intensity at a certain time, C0 is the absorption peak intensity of the initial concentration), the degradation rate of dimethylnidazole (TDZ) is 93.5% under the conditions without the addition of three capture agents, the degradation rate of dimethylnidazole (TDZ) is 87.2% under the conditions with TBA, the degradation rate of dimethylnidazole (TDZ) is 64.6% under the conditions with AO, and the degradation rate of dimethylnidazole (TDZ) is 25.5% under the conditions with BQ. By comparing the data in the presence of different capture agents, it is found that the photodegradation of dimethylnidazole (TDZ) is caused by·O2 - It is dominated by free radicals and photogenerated holes.

[0048] like Figure 12 As shown in the figure, the kinetic study test shows that with Ln(C0 / C) as the ordinate and the reaction time t as the abscissa, the linear coefficients of the function graphs obtained are: NFT: 0.9826, ODZ: 0.9889, TDZ: 0.9840, which indicates that the degradation reaction of the cobalt metal organic framework material to the three antibiotics conforms to the kinetic first-order reaction characteristics, and the rate constants of the degradation reaction within 20 minutes are 0.0740min -1 、0.1015min -1 、0.1373min -1 .

[0049] like Figure 13As shown, the reusability of the Co-MOF catalyst was tested. After the degradation reaction, the Co-MOF was centrifuged, washed, and dried before being used in the next dimetridazole (TDZ) degradation reaction. The experimental results showed that after four cycles, the catalytic activity of the Co-MOF did not significantly degrade, indicating the high reusability of the Co-MOF.

[0050] In summary, the cobalt metal-organic framework prepared by the present invention photocatalytically degraded ornidazole (ODZ) at a rate of 85.8% within 20 minutes; nitrofurantoin (NFT) at a rate of 81.5%; and dimetridazole (TDZ) at a rate of 93.5%. The cobalt metal-organic framework exhibited good photocatalytic degradation of all three antibiotics, especially TDZ. Cobalt metal-organic frameworks can be used as potential photocatalysts for the degradation of antibiotics in water.

[0051] Therefore, the present invention adopts the above-mentioned cobalt metal organic framework material and 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.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to 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 ; Wherein L is 4'-(4-carboxyphenoxy)-4-biphenylcarboxylic acid, bibp is 4,4'-bis(imidazolyl)biphenyl, n represents the degree of polymerization and is a positive integer. The cobalt metal organic framework material belongs to the orthorhombic crystal system and the Fddd space group.

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 distorted trigonal bipyramid configuration with the three coordinated oxygen atoms O1, O3 and O4 of two 4'-(4-carboxyphenoxy)-4-bibenzoic acids and the two coordinated nitrogen atoms N1 and N2 of one 4,4'-bis(imidazolyl)biphenyl; O4, N1 and N2 occupy the triangular face vertices of the distorted trigonal bipyramid, and O1 and O3 occupy the two vertices of the distorted trigonal bipyramid; in the distorted trigonal bipyramid configuration, the bond length of Co-O is 1.9700~2.4183Å, the bond length of Co-N is 2.0226Å, 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.

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 and 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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