A polypyrrole / zirconium-based metal-organic framework composite material, preparation method and application

Abstract

The present invention discloses a polypyrrole / zirconium-based metal-organic framework composite material, a preparation method and an application. By first pre-introducing pyrrole monomers into the synthesis system of zirconium-based metal-organic frameworks, a zirconium-based metal-organic framework material doped with pyrrole monomers is obtained, and then the pyrrole monomers are polymerized under the action of an oxidant to form polypyrrole, so that the polypyrrole is in-situ doped in the pores of the zirconium-based metal-organic framework material, thereby obtaining the polypyrrole / zirconium-based metal-organic framework composite material. This composite material has a large specific surface area, uniform size, and polypyrrole is uniformly distributed in the pores; when the polypyrrole / zirconium-based metal-organic framework composite material is used for the degradation of conventional tetracycline and high-salt tetracycline water bodies in the non-stirring mode, it shows excellent photocatalytic degradation performance. Because it is insensitive to the salinity in the water body, it is particularly suitable for the treatment of high-salt tetracycline water bodies. In addition, the preparation method of the present invention has a simple synthesis process and a short cycle, and is suitable for popularization and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials, and particularly relates to a polypyrrole / zirconium-based metal-organic framework composite material, a preparation method and an application thereof. Background Art

[0002] Antibiotics are chemicals widely used in aquaculture feeding and the treatment of animal and human diseases, such as tetracyclines, penicillins, sulfonamides, quinolones, and macrolides. Due to overuse, antibiotics are often detected in water environments, including groundwater, river water, surface water, and drinking water. The long-term presence of antibiotics in the environment has led to the spread of biological antibiotic resistance, thereby damaging the ecosystem and threatening human health. Therefore, there is an urgent need to explore feasible and effective materials and methods to remove antibiotics from water. At the same time, actual antibiotic water bodies generally have the characteristic of high salinity, further increasing the difficulty of antibiotic treatment.

[0003] In recent years, metal-organic frameworks (MOFs) have received extensive attention as emerging photocatalytic materials due to their many advantages such as flexible and adjustable structures, rich functional groups, high porosity (abundant pores), large specific surface area, and good thermal stability. Currently, light-driven metal-organic framework (MOFs)-based micro-nano motors with degradation characteristics have attracted the attention of many scholars for the degradation of water pollutants in the non-stirring mode. However, they have deficiencies such as low ion tolerance, which limits the gain effect brought by their movement and their application in actual high-salt sewage.

[0004] Polypyrrole is a common conductive polymer. By combining it with MOFs, the motility and ion tolerance can be improved, and the photocatalytic effect can be further enhanced. Currently reported methods for the composite of polypyrrole and MOFs are as follows: (1) direct coating method: directly coating the already synthesized polypyrrole nanoparticles during the synthesis of MOFs. However, this method will cause the pores of the metal-organic framework to be blocked by the polypyrrole nanoparticles, resulting in a significant decrease in the specific surface area. At the same time, the PPy loading rate in the obtained composite material is low and unevenly distributed; (2) immersion method: immersing pyrrole monomers in the already synthesized MOFs and then polymerizing. Although this method solves the problem of a significant decrease in the specific surface area through doping, its preparation cycle is long.

[0005] In view of this, the present invention has developed a simple and rapid method for preparing a polypyrrole / zirconium-based metal-organic framework composite material, and studied the application of the polypyrrole / zirconium-based metal-organic framework composite material prepared by this method in the degradation of tetracycline in the non-stirring mode, especially in high-salt tetracycline water bodies. Summary of the Invention

[0006] Aiming at the technical problems in the background art, the purpose of the present invention is to provide a polypyrrole / zirconium-based metal-organic framework composite material, a preparation method and an application; the prepared polypyrrole / zirconium-based metal-organic framework composite material exhibits excellent photocatalytic degradation effect as a photocatalyst in the degradation of tetracycline water bodies in the non-stirring mode (high salt).

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention is to provide a preparation method of a polypyrrole / zirconium-based metal-organic framework composite material, comprising the following steps:

[0009] S1. Mix a zirconium salt, a polycarboxylic acid organic ligand, a pyrrole (Py) monomer and N,N-dimethylformamide to obtain a mixture;

[0010] S2. Carry out a solvothermal reaction on the obtained mixture to obtain a zirconium-based metal-organic framework material doped with pyrrole monomers;

[0011] S3. Mix the obtained zirconium-based metal-organic framework material doped with pyrrole monomers with an oxidant, stir, and carry out a chemical oxidation reaction to obtain a polypyrrole / zirconium-based metal-organic framework composite material.

[0012] Preferably, in step S1, the mass ratio of the zirconium salt to the pyrrole monomer is 50:1-5, and further preferably 50:3.

[0013] Preferably, the zirconium salt is selected from one or a combination of two or more of zirconium oxychloride octahydrate, zirconium chloride, zirconium nitrate pentahydrate, and zirconyl nitrate, and further preferably zirconium oxychloride octahydrate.

[0014] Preferably, the mass ratio of the zirconium salt to the polycarboxylic acid organic ligand is 5:1-5, and further preferably 2:1;

[0015] Preferably, the dosage ratio of the zirconium salt to DMF is 50 mg:10-15 mL.

[0016] Preferably, the polyacid organic ligand is selected from one or a combination of two or more of meso - tetra(4 - carboxyphenyl) porphine (TCPP), 1,3,6,8 - tetra(4 - carboxyphenyl) pyrene, and terephthalic acid, and more preferably meso - tetra(4 - carboxyphenyl) porphine (TCPP). Different polyacid organic ligands will react with zirconium salts to obtain zirconium - based metal - organic framework materials with different topological structures. For example, when the polyacid organic ligand is meso - tetra(4 - carboxyphenyl) porphine (TCPP), it reacts with zirconium salts to form PCN - 222 and PCN - 224; when the polyacid organic ligand is 1,3,6,8 - tetra(4 - carboxyphenyl) pyrene, it reacts with zirconium salts to form NU - 1000; when the polyacid organic ligand is terephthalic acid, it reacts with zirconium salts to form UiO - 66 and UiO - 67.

[0017] Preferably, in step S2, the solvothermal reaction temperature is 60 - 120 °C and the time is 18 - 26 h.

[0018] In step S2 of the present invention, by pre - introducing pyrrole monomers into the system for synthesizing zirconium - based metal - organic frameworks, zirconium - based metal - organic framework materials doped with pyrrole monomers are successfully obtained. The present invention finds that the introduction of pyrrole monomers does not affect the synthesis of zirconium - based metal - organic frameworks.

[0019] In step S3 of the present invention, under the action of an oxidant, the pyrrole monomers in the pores are successfully polymerized to obtain polypyrrole.

[0020] Preferably, the dosage ratio of the oxidant to the pyrrole monomer is 3 - 10 g: 1 - 5 μL, and more preferably 2 - 3 g: 1 μL.

[0021] Preferably, the oxidant is selected from one or a combination of two or more of ferric chloride (FeCl3), ammonium persulfate ((NH4)2S2O8), and hydrogen peroxide (H2O2).

[0022] Preferably, in step S3, the temperature of the chemical oxidation reaction is 0 - 5 °C and the stirring time is 20 - 24 h.

[0023] The second aspect of the present invention provides a polypyrrole / zirconium - based metal - organic framework composite material prepared by the above - mentioned preparation method. The size of the polypyrrole / zirconium - based metal - organic framework composite material is uniform, and polypyrrole is uniformly distributed in the pores.

[0024] The third aspect of the present invention provides the application of the above - mentioned polypyrrole / zirconium - based metal - organic framework composite material as a photocatalyst in the degradation of tetracycline (in the non - stirring mode).

[0025] The fourth aspect of the present invention provides the application of the above-mentioned polypyrrole / zirconium-based metal-organic framework composite material as a photocatalyst in the degradation of tetracycline in a high-salinity water environment.

[0026] The present invention has the following beneficial effects:

[0027] (1) The polypyrrole / zirconium-based metal-organic framework composite material of the present invention is prepared by using zirconium salt, polycarboxylic acid organic ligand, pyrrole monomer and N,N-dimethylformamide as raw materials. Specifically, the pyrrole monomer is pre-loaded by mixing, and then the pyrrole monomer is polymerized by chemical oxidation to obtain polypyrrole. That is, the pyrrole monomer is first put into the synthesis system of the zirconium-based metal-organic framework to obtain a zirconium-based metal-organic framework material doped with the pyrrole monomer, and then the pyrrole monomer is polymerized under the action of an oxidant to obtain polypyrrole, and the polypyrrole is successfully in-situ doped into the pores of the zirconium-based metal-organic framework material, thus obtaining the polypyrrole / zirconium-based metal-organic framework composite material. The experimental results show that the polypyrrole / zirconium-based metal-organic framework composite material has a large specific surface area, uniform size, and polypyrrole is uniformly distributed in the pores, and at the same time has a high polypyrrole loading rate.

[0028] (2) The experimental results show that when the polypyrrole / zirconium-based metal-organic framework composite material prepared by the present invention is used as a catalyst for the degradation of tetracycline in water (in the non-stirring mode), it shows excellent photocatalytic degradation performance. This is because the introduction of PPy can not only effectively enhance the utilization of light, especially visible light, but also increase the thermal motion of the zirconium-based metal-organic framework material, and at the same time improve the generation of free radicals, thereby achieving better photocatalytic degradation performance.

[0029] (3) The experimental results show that the polypyrrole / zirconium-based metal-organic framework composite material prepared by the present invention as a catalyst is also suitable for the degradation of high-salinity tetracycline water in the non-stirring mode, and shows excellent photocatalytic degradation performance. This is because the photomovement of the polypyrrole / zirconium-based metal-organic framework composite material prepared by the present invention is insensitive to salinity, and can maintain thermal motion even in a high-salinity environment. Moreover, the holes generated by photoexcitation can also activate Cl ions to generate chlorine radicals, further improving its photocatalytic degradation performance.

[0030] (4) Compared with the polypyrrole / zirconium-based metal-organic framework composite materials prepared by the existing direct coating method and immersion method, the polypyrrole / zirconium-based metal-organic framework composite material prepared by the method of the present invention has a higher specific surface area, and the larger specific surface area is more conducive to its subsequent photocatalytic degradation of tetracycline as a catalyst.

[0031] (5) In the preparation method of the present invention, by doping pyrrole monomers during the synthesis of MOFs, not only can the process cycle be effectively shortened, but also the polypyrrole formed by subsequent polymerization of pyrrole monomers can be evenly distributed in the pores of MOFs. The preparation method of the present invention has the characteristics of simple process and short cycle, and is suitable for large-scale popularization and application. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0033] Figure 1 SEM images of various samples: (a) polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 1; (b) physically broken polypyrrole / zirconium-based metal-organic framework composite material; (c) zirconium-based metal-organic framework material prepared in Comparative Example 1.

[0034] Figure 2 SEM images of the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 4 (a) and the zirconium-based metal-organic framework material prepared in Comparative Example 2 (b);

[0035] Figure 3 SEM images of the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 5 (a) and the zirconium-based metal-organic framework material prepared in Comparative Example 3 (b);

[0036] Figure 4 XRD patterns of the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 1 and the zirconium-based metal-organic framework material prepared in Comparative Example 1;

[0037] Figure 5 XRD patterns of the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 4 and the zirconium-based metal-organic framework material prepared in Comparative Example 2;

[0038] Figure 6 XRD patterns of the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 5 and the zirconium-based metal-organic framework material prepared in Comparative Example 3;

[0039] Figure 7 Degradation effect diagrams of the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 1 and the zirconium-based metal-organic framework material prepared in Comparative Example 1 as catalysts applied to the degradation of tetracycline without NaCl (conventional) and high-salt tetracycline in the visible light non-stirring mode. Detailed Embodiments

[0040] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details.

[0041] Example 1

[0042] A method for preparing a polypyrrole / zirconium-based metal-organic framework composite material includes the following steps:

[0043] 1) Mix 50 mg of zirconium oxychloride octahydrate, 25 mg of meso-tetrakis(4-carboxyphenyl)porphine (TCPP), 4 mL of acetic acid, 3 μL of pyrrole (Py) monomer, and 12 mL of N,N-dimethylformamide evenly by stirring to obtain a mixture;

[0044] 2) Carry out a solvothermal reaction on the mixture at 65 °C for 24 h. After the reaction is completed, add the product to ethanol and centrifuge and wash three times to obtain a zirconium-based metal-organic framework material doped with pyrrole monomer;

[0045] 3) Mix the obtained zirconium-based metal-organic framework material doped with pyrrole monomer with 30 mL of an aqueous solution containing 3 g of ferric chloride (FeCl3), stir magnetically at 0 °C, and carry out a chemical oxidation reaction for 24 h. After the reaction is completed, add the final product to ethanol and centrifuge and wash three times to obtain a polypyrrole / zirconium-based metal-organic framework composite material, where the polypyrrole content is 6%, denoted as PCN-PPy. Through the N2 adsorption-desorption curve test, its BET specific surface area is 2054 m 2 ·g -1 .

[0046] Example 2

[0047] It is basically the same as Example 1, except that "25 mg of meso-tetrakis(4-carboxyphenyl)porphine (TCPP)" is replaced with "50 mg of meso-tetrakis(4-carboxyphenyl)porphine (TCPP)", and "3 μL of pyrrole" is replaced with "1 μL of pyrrole", and finally a polypyrrole / zirconium-based metal-organic framework composite material is obtained.

[0048] Example 3

[0049] It is basically the same as Example 1, except that "25 mg of meso-tetrakis(4-carboxyphenyl)porphine (TCPP)" is replaced with "10 mg of meso-tetrakis(4-carboxyphenyl)porphine (TCPP)", and "3 μL of pyrrole" is replaced with "5 μL of pyrrole", and finally a polypyrrole / zirconium-based metal-organic framework composite material is obtained;

[0050] Example 4

[0051] It is basically the same as Example 1, except that "25 mg of meso-tetrakis(4-carboxyphenyl)porphine (TCPP)" is replaced with "20 mg of 1,3,6,8-tetrakis(4-carboxyphenyl)pyrene", and "3 μL of pyrrole" is replaced with "1 μL of pyrrole". Finally, a polypyrrole / zirconium-based metal-organic framework composite material is obtained, in which the polypyrrole content is 2%, denoted as NU-PPy.

[0052] Example 5

[0053] It is basically the same as Example 1, except that "meso-tetrakis(4-carboxyphenyl)porphine (TCPP)" is replaced with "terephthalic acid", "zirconium oxychloride octahydrate" is replaced with "zirconium chloride", and "3 μL of pyrrole" is replaced with "1 μL of pyrrole". Finally, a polypyrrole / zirconium-based metal-organic framework composite material is obtained, in which the polypyrrole content is 3%, denoted as UiO-PPy.

[0054] Comparative Example 1

[0055] It is basically the same as Example 1, except that the pyrrole (Py) monomer is not added, and finally a zirconium-based metal-organic framework material is obtained.

[0056] Comparative Example 2

[0057] It is basically the same as Example 4, except that the pyrrole (Py) monomer is not added, and finally a zirconium-based metal-organic framework material is obtained.

[0058] Comparative Example 3

[0059] It is basically the same as Example 5, except that the pyrrole (Py) monomer is not added, and finally a zirconium-based metal-organic framework material is obtained.

[0060] Comparative Example 4

[0061] (1) 50 mg of zirconium oxychloride octahydrate, 25 mg of meso-tetrakis(4-carboxyphenyl)porphine (TCPP), 4 mL of acetic acid and 12 mL of N,N-dimethylformamide were mixed and stirred evenly to obtain a mixture; a solvothermal reaction was carried out, and the final product was added to ethanol and centrifugally washed three times to obtain a zirconium-based metal-organic framework material;

[0062] (2) 40 mg of the obtained zirconium-based metal-organic framework material was immersed in a solution containing 3 μL of pyrrole (Py) monomer, and then mixed with 30 mL of an aqueous solution containing 3 g of ferric chloride (FeCl3), and magnetically stirred at 0 °C for 24 h. The final product was added to ethanol and centrifugally washed three times to obtain a polypyrrole / zirconium-based metal-organic framework composite material. Through the N2 adsorption-desorption curve test, its BET specific surface area was 1881 m 2 ·g -1 .

[0063] Comparative Example 5

[0064] 50 mg of zirconium oxychloride octahydrate, 25 mg of meso-tetrakis(4-carboxyphenyl)porphine (TCPP), 4 mL of acetic acid, 3 mg of PPy nanoparticles and 12 mL of N,N-dimethylformamide were mixed and stirred evenly to obtain a mixture; a solvothermal reaction was carried out. After adding ethanol to the final product and centrifuging and washing three times, the polypyrrole / zirconium-based metal-organic framework composite material was obtained. Through the N2 adsorption-desorption curve test, its BET specific surface area was 515 m 2 ·g -1 .

[0065] The polypyrrole / zirconium-based metal-organic framework composite materials prepared in Examples 1, 4, and 5 and the zirconium-based metal-organic framework materials prepared in Comparative Examples 1-3 were respectively subjected to morphological characterization, and the SEM images obtained are as Figure 1-3 shown.

[0066] From Figure 1 (a), it can be seen that the morphology of the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 1 is cubic (the particle diameter size is about 1.5 μm), and the size distribution is uniform.

[0067] From Figure 1 (b), it can be seen that after physically crushing the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 1, polypyrrole nanoparticles can be observed to be uniformly distributed in the pores in the internal cross-section of the sample. By the amount of Py monomer added before the reaction and the total mass of the obtained sample, the PPy content in the obtained composite material was estimated to be 6%.

[0068] From Figure 1 (c), it can be seen that the morphology of the zirconium-based metal-organic framework material prepared in Comparative Example 1 is cubic (the particle diameter size is about 1.5 μm), and the size distribution is uniform.

[0069] From Figure 2 (a), it can be seen that the morphology of the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 4 is rod-shaped (the length is about 3 μm and the diameter is about 1 μm), the size distribution is uniform, and there is a slight depression in the middle.

[0070] From Figure 2 (b), it can be seen that the morphology of the zirconium-based metal-organic framework material prepared in Comparative Example 2 is rod-shaped (the length is about 3 μm and the diameter is about 1 μm), and the size distribution is uniform.

[0071] From Figure 3(a) It can be seen from the results that the morphology of the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 5 is octahedral (with a diameter of about 1 μm), and the size distribution is uniform.

[0072] From Figure 3 (b) It can be seen from the results that the morphology of the zirconium-based metal-organic framework material prepared in Comparative Example 3 is octahedral (with a diameter of about 1 μm), and the size distribution is uniform.

[0073] XRD characterization was performed on the polypyrrole / zirconium-based metal-organic framework composite materials prepared in Examples 1, 4, and 5 and the zirconium-based metal-organic framework materials prepared in Comparative Examples 1-3, and the XRD patterns are as Figure 4-6 shown.

[0074] From Figure 4 the results, it can be seen that the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 1 (denoted as PCN-PPy in the figure) has good crystallinity, showing the characteristic layered diffraction peaks of the zirconium-based metal-organic framework material at a diffraction angle of 3-30°, and the positions of all the diffraction peaks of the zirconium-based metal-organic framework material correspond one by one to the positions of the diffraction peaks of the known PCN-224 crystal structure. This indicates that the zirconium-based metal-organic framework material in the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 1 has the same crystal structure as PCN-224, that is, the zirconium-based metal-organic framework material in the polypyrrole / zirconium-based metal-organic framework composite material prepared in Example 1 is PCN-224.

[0075] Figure 4 The results also show that the zirconium-based metal-organic framework material prepared in Comparative Example 1 (denoted as PCN-224 in the figure) has good crystallinity, showing the characteristic layered diffraction peaks of the zirconium-based metal-organic framework material at a diffraction angle of 3-30°, and the positions of all the diffraction peaks of the zirconium-based metal-organic framework material correspond one by one to the positions of the diffraction peaks of the known PCN-224 crystal structure. This indicates that the zirconium-based metal-organic framework material prepared in Comparative Example 1 has the same crystal structure as PCN-224, that is, the zirconium-based metal-organic framework material prepared in Comparative Example 1 is PCN-224.

[0076] From Figure 5It can be seen from the results that the poly(3,4-ethylenedioxythiophene) / zirconium-based metal-organic framework composite material prepared in Example 4 (denoted as NU-PPy in the figure) has good crystallization performance, showing the characteristic layered diffraction peaks of zirconium-based metal-organic framework materials at diffraction angles of 3-30°. Moreover, the positions of all the diffraction peaks of the zirconium-based metal-organic framework material in the poly(3,4-ethylenedioxythiophene) / zirconium-based metal-organic framework composite material prepared in Example 4 correspond one by one to the positions of the diffraction peaks of the known NU-1000 crystal structure. This indicates that the zirconium-based metal-organic framework material in the poly(3,4-ethylenedioxythiophene) / zirconium-based metal-organic framework composite material prepared in Example 4 has the same crystal structure as NU-1000, that is, the zirconium-based metal-organic framework material in the poly(3,4-ethylenedioxythiophene) / zirconium-based metal-organic framework composite material prepared in Example 4 is NU-1000.

[0077] Figure 5 The results also show that the zirconium-based metal-organic framework material prepared in Comparative Example 2 (denoted as NU-1000 in the figure) has good crystallization performance, showing the characteristic layered diffraction peaks of zirconium-based metal-organic framework materials at diffraction angles of 3-30°. And the positions of all the diffraction peaks of the zirconium-based metal-organic framework material correspond one by one to the positions of the diffraction peaks of the known NU-1000 crystal structure. This indicates that the zirconium-based metal-organic framework material prepared in Comparative Example 2 has the same crystal structure as NU-1000, that is, the zirconium-based metal-organic framework material prepared in Comparative Example 2 is NU-1000.

[0078] From Figure 6 It can be seen from the results that the poly(3,4-ethylenedioxythiophene) / zirconium-based metal-organic framework composite material prepared in Example 5 (denoted as UiO-PPy in the figure) has good crystallization performance, showing the characteristic layered diffraction peaks of zirconium-based metal-organic framework materials at diffraction angles of 3-30°. Moreover, the positions of all the diffraction peaks of the zirconium-based metal-organic framework material correspond one by one to the positions of the diffraction peaks of the known UiO-66 crystal structure. This indicates that the zirconium-based metal-organic framework material in the poly(3,4-ethylenedioxythiophene) / zirconium-based metal-organic framework composite material prepared in Example 5 has the same crystal structure as UiO-66, that is, the zirconium-based metal-organic framework material in the poly(3,4-ethylenedioxythiophene) / zirconium-based metal-organic framework composite material prepared in Example 5 is UiO-66.

[0079] Figure 6 The results also show that the zirconium-based metal-organic framework material prepared in Comparative Example 3 (denoted as UiO-66 in the figure) has good crystallization performance, showing the characteristic layered diffraction peaks of zirconium-based metal-organic framework materials at diffraction angles of 3-30°. And the positions of all the diffraction peaks of the zirconium-based metal-organic framework material correspond one by one to the positions of the diffraction peaks of the known UiO-66 crystal structure. This indicates that the zirconium-based metal-organic framework material has the same crystal structure as UiO-66, that is, the zirconium-based metal-organic framework material prepared in Comparative Example 3 is UiO-66.

[0080] The above SEM and XRD experimental results prove that the in-situ doped zirconium-based metal-organic framework material with polypyrrole has been successfully prepared by the present invention. The above results also show that in the process of preparing the polypyrrole / zirconium-based metal-organic framework composite material (i.e., the zirconium-based metal-organic framework material doped with polypyrrole) by polymerizing polypyrrole nanoparticles in the pores under the action of an oxidant in the zirconium-based metal-organic framework material doped with pyrrole monomers, the original zirconium-based metal-organic framework material will not be affected in terms of morphology or size.

[0081] Test Example 1

[0082] The polypyrrole / zirconium-based metal-organic framework composite material (PCN-PPy) prepared in Example 1 was used as a photocatalyst for the degradation of tetracycline in a high-salinity water environment. The degradation performance of the material was achieved by degrading tetracycline under visible light. A 300W xenon lamp was used as the light source, and the light intensity was 400mW·cm -2 . The experimental device was in a closed experimental environment to exclude the interference of external light sources to ensure the reliability and authenticity of the experimental data results.

[0083] Specific steps: Add 5mg of PCN-PPy (as a catalyst) to a glass bottle containing 30mL of a tetracycline solution (200mg·L -1 ) and 5mg of potassium persulfate (PMS). Before illumination, magnetically stir the suspension in the dark for 30 min to achieve the adsorption-desorption equilibrium between PCN-PPy and tetracycline; then stop magnetic stirring, expose it to the light source, extract about 1mL of the suspension at specific time intervals with a syringe, and completely remove the PCN-PPy powder through a 0.22μm polytetrafluoroethylene syringe filter; then analyze the remaining concentration of tetracycline by ultraviolet-visible spectroscopy (the characteristic absorption peak of tetracycline at 357nm) to obtain the degradation curve of photocatalytic high-salinity tetracycline. The results are as Figure 7 shown.

[0084] Application Example 2

[0085] The steps are basically the same as those in Application Example 1, except that the "tetracycline solution containing 1M NaCl (200mg·L -1 )" is replaced with "tetracycline solution (200mg·L -1 )". The obtained results are as Figure 7 shown.

[0086] Application Comparative Example 1

[0087] The steps are basically the same as those in Application Example 1, except that "5mg of PCN-PPy" is replaced with "5mg of the zirconium-based metal-organic framework material (PCN-224) prepared in Comparative Example 1", and the obtained results are asFigure 7 as shown

[0088] Application Comparative Example 2

[0089] was basically the same as the steps of Application Example 2, except that "5 mg of PCN-PPy" was replaced with "5 mg of the zirconium-based metal-organic framework material (PCN-224) prepared in Comparative Example 1", and the result was as Figure 7 shown

[0090] From Figure 7 the results, it can be seen that when using PCN-PPy as a catalyst for the degradation of conventional tetracycline (without NaCl), the degradation rate at 5 min was 60%, and the degradation rate at 30 min was 80%; while when using the zirconium-based metal-organic framework material prepared in Comparative Example 1 as a catalyst, the degradation rate at 5 min was 40% under the same environment, and the degradation rate at 30 min was only 60%; when using PCN-PPy as a catalyst for the degradation of high-salt tetracycline, the degradation rate of tetracycline hydrochloride (TCH) within 5 min was 80%, and it reached 95% at 10 min, and the degradation was basically completed. While when using the zirconium-based metal-organic framework material (denoted as PCN-224 in the figure) prepared in Comparative Example 1 as a catalyst, the degradation rate at 5 min was 50% under the same environment, and the degradation rate at 30 min was only 72%. Compared with the zirconium-based metal-organic framework material, the polypyrrole / zirconium-based metal-organic framework composite material prepared by in-situ doping of polypyrrole into the zirconium-based metal-organic framework by the method of the present invention as a catalyst can efficiently achieve the degradation of conventional tetracycline (without NaCl) and high-salt tetracycline, which can be attributed to the following two aspects: (1) PPy in the polypyrrole / zirconium-based metal-organic framework composite material can effectively enhance the utilization of light, especially visible light, increase the thermal motion of the zirconium-based metal-organic framework, and at the same time improve the generation efficiency of free radicals, thereby achieving a better degradation effect; (2) in a high-salt (NaCl) system, the holes generated by the polypyrrole / zirconium-based metal-organic framework composite material can activate Cl ions to generate chlorine free radicals, thereby further improving its degradation effect.

[0091] The present invention is not limited to the above specific embodiments. Those of ordinary skill in the art starting from the above concepts and making various changes without creative labor fall within the protection scope of the present invention.

Claims

1. A preparation method of a polypyrrole / zirconium-based metal-organic framework composite material, characterized in that It includes the following steps: S1. Mix a zirconium salt, a polyacid organic ligand, a pyrrole monomer, and N,N-dimethylformamide to obtain a mixture; The mass ratio of the zirconium salt to the pyrrole monomer is 50:1 - 5; the mass ratio of the zirconium salt to the polyacid organic ligand is 5:1 - 5; the polyacid organic ligand is selected from meso-tetrakis(4-carboxyphenyl)porphine; S2. Carry out a solvothermal reaction on the obtained mixture to obtain a zirconium-based metal-organic framework material doped with the pyrrole monomer; S3. Mix the obtained zirconium-based metal-organic framework material doped with the pyrrole monomer with an oxidant, stir, and carry out a chemical oxidation reaction to obtain a polypyrrole / zirconium-based metal-organic framework composite material.

2. The preparation method of the polypyrrole / zirconium-based metal-organic framework composite material according to claim 1, wherein, In step S1, the zirconium salt is selected from one or a combination of two or more of zirconium oxychloride octahydrate, zirconium chloride, zirconium nitrate pentahydrate, and zirconyl nitrate.

3. The preparation method of the polypyrrole / zirconium-based metal-organic framework composite material according to claim 1, characterized in that, In step S2, the temperature of the solvothermal reaction is 60 - 120°C, and the time is 18 - 26 h.

4. The preparation method of the polypyrrole / zirconium-based metal-organic framework composite material according to claim 1, wherein, The dosage ratio of the oxidant to the pyrrole monomer is 3 - 10 g:1 - 5 μL; the oxidant is selected from one or a combination of two or more of ferric chloride, ammonium persulfate, and hydrogen peroxide.

5. The preparation method of the polypyrrole / zirconium-based metal-organic framework composite material according to claim 1, wherein In step S3, the temperature of the chemical oxidation reaction is 0 - 5°C, and the stirring time is 20 - 24 h.

6. A polypyrrole / zirconium-based metal-organic framework composite material prepared by the preparation method according to any one of claims 1 - 5.

7. Application of the polypyrrole / zirconium-based metal-organic framework composite material according to claim 6 as a photocatalyst in the degradation of tetracycline.

8. Use of the polypyrrole / zirconium-based metal-organic framework composite material according to claim 7 as a photocatalyst in the degradation of tetracycline, characterized in that, The degradation of tetracycline is the degradation of tetracycline in a non-stirring mode.

9. Use of the polypyrrole / zirconium-based metal-organic framework composite material according to claim 7 as a photocatalyst in the degradation of tetracycline, characterized in that, The degradation of tetracycline is the degradation of tetracycline in a high-salt environment.

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