Biological enzyme (at) MOFs / silver phosphate-based composite material, preparation method thereof and application of composite material in water treatment

Abstract

The invention discloses a biological enzyme (at) MOFs / silver phosphate-based composite material and a preparation method and application thereof in water treatment. The preparation method of the composite material comprises the following steps: adding a biological enzyme and a dispersing agent into an organic ligand solution, and uniformly mixing to obtain a mixed solution; adding a metal source solution into the mixed solution, stirring for reaction, filtering, and drying filter residues to obtain a biological enzyme-coated MOFs material; and adding the bio-enzyme-coated MOFs material into a silver phosphate solution, carrying out mixing reaction, and drying the obtained solid to obtain the bio-enzyme-coated MOFs / silver phosphate-based composite material. The composite material disclosed by the invention not only can maintain the catalytic activity and stability of enzyme, but also has efficient photocatalytic activity under illumination; the MOFs, the photocatalytic material and the bio-enzyme promote each other, and finally the composite material shows good antibacterial and antibiotic degradation effects.

Description

Technical Field

[0001] The present invention belongs to the cross-field of environmental engineering, nanomaterial science and bioengineering, and specifically relates to a bioenzyme@MOFs / silver phosphate-based composite material, a preparation method thereof and an application thereof in water treatment. Background Art

[0002] With the acceleration of industrialization and urbanization, water pollution has become increasingly serious and has become one of the environmental issues of global concern. Various organic pollutants, including antibiotics and pathogenic microorganisms, enter water bodies through industrial wastewater, agricultural runoff, and domestic sewage, posing a serious threat to the ecological environment and human health. Traditional water treatment technologies, such as physical adsorption, chemical oxidation, and biodegradation, have problems such as low efficiency, high treatment costs, and secondary pollution when dealing with complex and diverse water pollutants. Therefore, the development of new water treatment materials that are efficient, environmentally friendly, and have broad-spectrum antibacterial and antibiotic degradation capabilities has become a technical problem that needs to be solved urgently.

[0003] In the field of water pollution treatment, especially when using materials such as metal organic frameworks (MOFs), photocatalytic materials and bio-enzymes, there are some obvious disadvantages and limitations. These disadvantages mainly stem from the properties of the materials themselves, the interaction mechanism and their performance in practical applications. Specifically, the main disadvantages and their causes include: (1) Biological enzymes are unstable and easily inactivated: The natural structure of biological enzymes is relatively fragile and easily affected by the external environment, such as temperature, pH value, and organic solvents, which can cause the enzyme molecules to denature and become inactivated.

[0004] (2) Photocatalyst photogenerated electron-hole pairs are easy to recombine: In the photocatalytic process of traditional photocatalysts, the recombination rate of photogenerated electrons and holes is high, resulting in low photocatalytic efficiency. This problem is mainly due to the material properties of the photocatalyst. Photogenerated electrons and holes are easy to recombine after generation and cannot fully participate in the redox reaction, thereby reducing the generation of reactive oxygen species and affecting the antibacterial and organic pollutant degradation effects of the photocatalyst.

[0005] (3) Poor visible light response of photocatalysts: Most traditional photocatalysts perform well under ultraviolet light, but have poor response in the visible light range. This is because these photocatalytic materials have a wide band gap and can only absorb high-energy ultraviolet light, and cannot effectively utilize the larger visible light portion of the solar spectrum. Therefore, under natural light conditions, the actual application effect of photocatalysts is greatly reduced, limiting their widespread application.

[0006] (4) Poor dispersibility and stability of photocatalytic materials: Photocatalytic materials, such as titanium dioxide, easily aggregate in water, resulting in a decrease in specific surface area and reduced photocatalytic efficiency.

[0007] (5) The structural design of composite materials is complex and it is difficult to take into account multiple functions at the same time: The design of existing composite materials often faces problems such as complex structure and incompatible functions. In order to have efficient enzyme catalysis and photocatalysis at the same time, it is necessary to finely regulate the structure and function of the material. The combination of biological enzymes and photocatalytic materials needs to ensure that the two work together in the composite material, which involves many technical details such as the regulation of material surface properties, enzyme immobilization methods, and photocatalyst loading methods. If handled improperly, the overall performance of the material may be unsatisfactory and it may not be able to play the role of efficient antibacterial and antibiotic degradation at the same time.

[0008] In summary, these shortcomings of the existing technologies are mainly caused by the chemical and physical properties of the materials themselves, the complexity of the interactions, and the performance limitations in practical application environments. Therefore, the development of new, more efficient and more stable water treatment materials, as well as the improvement of the synthesis and application strategies of existing materials, are crucial to addressing these challenges. Summary of the invention

[0009] In order to overcome the shortcomings and deficiencies of the above-mentioned prior art, the primary purpose of the present invention is to provide a method for preparing a bio-enzyme@MOFs / silver phosphate-based composite material. The present invention improves the versatility and practicality of water pollution treatment materials by combining the high specific surface area and porous structure of MOFs, the photocatalytic properties of silver phosphate and the biocatalytic function of bio-enzymes.

[0010] Another object of the present invention is to provide a bio-enzyme@MOFs / silver phosphate-based composite material prepared by the above method.

[0011] Another object of the present invention is to provide an application of the above-mentioned bio-enzyme@MOFs / silver phosphate-based composite material in water treatment.

[0012] The purpose of the present invention is achieved through the following solutions: A method for preparing a bioenzyme@MOFs / silver phosphate-based composite material, comprising the following steps: (1) adding the biological enzyme and the dispersant to the organic ligand solution and mixing them evenly to obtain a mixed solution 1; (2) adding a metal source solution to the mixed solution 1, stirring for reaction, filtering, and drying the filter residue to obtain a bio-enzyme@MOFs material; (3) Adding the bio-enzyme@MOFs material to a silver phosphate solution, mixing and reacting, and drying the obtained solid to obtain a bio-enzyme@MOFs / silver phosphate-based composite material.

[0013] In some embodiments, the biological enzyme in step (1) includes at least one of catalase and glucose oxidase.

[0014] In some embodiments, the dispersant in step (1) includes at least one of polyvinyl pyrrolidone (PVP), cetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and polyvinyl alcohol (PVA).

[0015] In some embodiments, in the organic ligand solution of step (1), the mass ratio of the organic ligand to the solvent is 1:(30-200); the organic ligand includes at least one of 2-methylimidazole, benzimidazole, 2-ethylimidazole, terephthalic acid, and 1,4-cyclohexanedicarboxylic acid; and the solvent includes at least one of PBS buffer and water.

[0016] In some embodiments, the temperature for uniform mixing in step (1) is 20-40° C., the time for uniform mixing is 1-3 h, and the rotation speed is 100-300 rpm.

[0017] In some embodiments, the MOFs material in step (2) includes at least one of ZIF-67 nanoparticles and MIL-53 nanoparticles.

[0018] In some embodiments, in the metal source solution of step (2), the mass ratio of the metal source to the solvent is 1: (30-200); the metal source includes at least one of cobalt nitrate (Co(NO3)2·6H2O), cobalt chloride (CoCl2·6H2O), cobalt acetate (Co(CH3COO)2·4H2O), aluminum nitrate nonahydrate (Al(NO3)3·9H2O), aluminum chloride hexahydrate (AlCl3·6H2O), and chromium sulfate (Cr2(SO4)3); and the solvent includes at least one of PBS buffer and water.

[0019] In some embodiments, the stirring reaction in step (2) is carried out at a temperature of 20-40° C., a time of 10-16 h, and a rotation speed of 100-300 rpm.

[0020] In some embodiments, the drying in step (2) is low-temperature vacuum drying, the drying temperature is -70 to -90°C, and the drying time is 10-16 hours.

[0021] In some embodiments, in the silver phosphate solution of step (3), the mass ratio of silver phosphate to solvent is 1:(100-400); the solvent comprises at least one of ethanol, methanol, dimethyl sulfoxide, N,N-dimethylformamide, and water.

[0022] In some embodiments, the temperature of the mixed reaction in step (3) is 20-40° C., the time of the mixed reaction is 10-16 h, and the rotation speed is 100-300 rpm.

[0023] In some embodiments, the drying in step (3) is low-temperature vacuum drying, the drying temperature is -70 to -90°C, and the drying time is 10-16 hours.

[0024] In some embodiments, the mass ratio of the biological enzyme to the organic ligand in step (1) is 1:(4-20), preferably 1:9; the mass ratio of the biological enzyme to the dispersant in step (1) is (5-20):1, preferably 10:1.

[0025] In some embodiments, the mass ratio of the organic ligand in the organic ligand solution in step (1) to the metal source in the metal source solution in step (2) is (1-2.5):1, preferably 1.8:1.

[0026] In some embodiments, the mass ratio of the bio-enzyme@MOFs material to the silver phosphate in step (3) is 1:(0.1-1), preferably 1:0.3.

[0027] Bioenzymes have shown great potential in the degradation of water pollutants due to their high catalytic activity and specificity. However, bioenzymes generally have problems such as poor stability and easy inactivation in practical applications, which limits their widespread application in the field of water treatment. In order to improve the stability and reuse rate of enzymes, enzyme immobilization technology has emerged. In recent years, metal-organic framework materials (MOFs) have become ideal enzyme immobilization carriers due to their high specific surface area, adjustable pore structure and excellent chemical stability. By encapsulating bioenzymes in MOFs, not only can the stability of the enzymes be improved, but also their biocatalytic activity can be maintained, providing a new way for the efficient degradation of water pollutants.

[0028] Photocatalytic technology is a green and environmentally friendly water treatment method that can use light energy to degrade organic pollutants into harmless small molecules. The active oxygen species generated by photocatalysts under light conditions, such as hydroxyl radicals and superoxide anions, have strong oxidizing properties and can effectively kill pathogenic microorganisms in water and degrade organic pollutants such as antibiotics. Using silver phosphate as the photocatalyst of the present invention can overcome the problems of traditional photocatalysts such as TiO2, such as easy recombination of photogenerated electron-hole pairs and poor visible light response, and can effectively improve the photocatalytic performance of the material.

[0029] Combining immobilized bioenzymes with silver phosphate photocatalytic materials to construct bioenzyme@MOFs silver phosphate-based composite materials is an innovative way to achieve water purification. This composite material can not only maintain the catalytic activity and stability of the enzyme, but also has efficient photocatalytic activity under light, achieving synergistic antibacterial and antibiotic degradation functions. By optimizing the enzyme immobilization technology, the photocatalytic material loading method and the structural design of the composite material, the overall performance of the composite material can be significantly improved. Combining bioenzymes with photocatalytic materials to prepare composite materials with efficient antibacterial and antibiotic degradation properties can solve the key technical problems in water pollution treatment. By optimizing the enzyme immobilization and photocatalytic material loading methods, and designing the composite material structure, the stability and long-term performance of the material are improved, ensuring its high efficiency and durability under different water quality conditions, and providing reliable guarantees for actual water treatment applications.

[0030] The present invention provides a bioenzyme@MOFs / silver phosphate-based composite material, and the bioenzyme@MOFs / silver phosphate-based composite material is prepared by the preparation method as described above.

[0031] The present invention provides an application of a bioenzyme@MOFs / silver phosphate-based composite material in water treatment.

[0032] In some embodiments, the water body is preferably a water body containing harmful bacteria, especially a water body containing Pseudomonas aeruginosa.

[0033] In some embodiments, the water body is preferably a water body containing antibiotics, preferably a water body containing ampicillin and / or diclofenac sodium.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects: The present invention effectively combines metal organic framework materials (MOFs), photocatalytic materials (silver phosphate) and biological enzymes to prepare biological enzymes @ MOFs / silver phosphate-based composite materials, which have significant multiple functions and advantages in water treatment applications: (1) Highly efficient antibacterial and pollutant degradation: The photocatalytic material in the composite material generates active oxygen species (such as hydroxyl radicals and superoxide anions) under light. These active oxygen species have strong oxidizing properties and can effectively destroy the cell walls and cell membranes of bacteria, thereby killing pathogenic microorganisms and degrading antibiotics and organic pollutants in water. It achieves the dual functions of high-efficiency antibacterial and organic pollutant degradation and is suitable for a variety of water treatment scenarios.

[0035] (2) Excellent visible light response ability: Silver phosphate-based photocatalytic material (Ag3PO4) has a narrow band gap and can effectively absorb visible light, thereby exhibiting high photocatalytic efficiency under natural light conditions, reducing dependence on artificial ultraviolet light sources, reducing operating costs, and being more environmentally friendly.

[0036] (3) Improving the stability and catalytic performance of bio-enzymes: Bio-enzymes are encapsulated inside MOFs, which effectively protects the enzyme molecules and prevents them from being inactivated in the water system, thereby improving the stability and catalytic efficiency of the bio-enzymes. This extends the service life of the bio-enzymes in practical applications and improves their catalytic antibacterial and pollutant degradation performance.

[0037] (4) Synergistic effect of materials: MOFs, photocatalytic materials and bio-enzymes promote each other and enhance the overall performance of the composite material. MOFs provide high specific surface area and porous structure, which is conducive to the loading and dispersion of photocatalytic materials and bio-enzymes; photocatalytic materials produce active oxygen species under light, which cooperate with the catalytic effect of bio-enzymes to further improve the antibacterial and degradation effects. The synergistic effect of materials significantly improves the effect of removing microorganisms and pollutants, and enhances the functionality and application range of composite materials.

[0038] (5) The composite material has good chemical stability: the biological enzyme and silver phosphate photocatalytic material are loaded into MOFs, and its stability is improved through the design of the composite material, thus avoiding the agglomeration and deactivation problems of the photocatalytic material.

[0039] (6) Complying with the requirements of environmental protection and sustainable development: Silver phosphate, as a chemical reagent, is highly toxic and corrosive, with a hazard level of 8. However, the present invention combines silver phosphate with biological enzymes and MOFs to prepare a composite material that greatly reduces the toxicity of silver phosphate. While achieving efficient sterilization, the composite material is not cytotoxic and is very safe to use. In addition, the present invention does not require the addition of additional chemical reagents during the photocatalytic process to prepare the biological enzyme @MOFs silver phosphate-based composite material, thereby avoiding the generation of harmful by-products. Through efficient biological enzymes and photocatalysis, the dependence on traditional chemical agents is reduced, and the risk of secondary pollution is reduced. Due to the high efficiency and reuse rate of the composite material, the energy consumption and material consumption in the water treatment process are reduced, and the economic benefits are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a scanning electron micrograph of the catalase@ZIF-67 material prepared in step (2) of Example 1.

[0041] Figure 2 This is a scanning electron micrograph of the catalase@ZIF-67 / silver phosphate-based composite material prepared in step (3) of Example 1.

[0042] Figure 3 This is a scanning electron micrograph of the catalase@MIL-53 material prepared in step (2) of Example 2.

[0043] Figure 4This is a scanning electron microscope image of the catalase@ZIF-90 material prepared in step (2) of Comparative Example 5.

[0044] Figure 5 This is the cell survival rate of the catalase@ZIF-67 / silver phosphate-based composite material prepared in Example 1 at a concentration of 10 μg / mL. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with the examples and drawings, but the embodiments of the present invention are not limited thereto. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0046] The concentration of the PBS buffer used in the present invention is 0.02 mol / L, and the pH is 6.5. The molecular weights of the polyvinyl pyrrolidone, polyethylene glycol and polyvinyl alcohol used in the present invention are between 7000-15000 Da.

[0047] Example 1 (1) Add 1.8 g of 2-methylimidazole to 100 mL of PBS buffer and mix well to obtain an organic ligand solution; add 0.2 g of catalase and 20 mg of polyvinyl pyrrolidone to the organic ligand solution, stir at 30°C and 200 rpm for 2 h to mix well to obtain a mixed solution; (2) Add 1 g of cobalt nitrate to 100 mL of PBS buffer and mix well to obtain a metal source solution; add the mixed solution to the metal source solution and stir at 30°C and 200 rpm for 12 h, filter and wash the precipitate with deionized water for 3 times, and vacuum dry at -80°C for 12 h to obtain catalase@ZIF-67 material; the scanning electron microscopy image of the catalase@ZIF-67 material is shown in FIG. Figure 1 shown.

[0048] (3) Add 0.3 g of silver phosphate (Ag3PO4) to 100 mL of methanol, mix well to obtain a silver phosphate solution, add 1 g of the catalase@ZIF-67 material of step (2), react at 30 °C and 200 rpm for 12 h, filter, wash the precipitate with deionized water three times, and vacuum dry at -80 °C for 12 h to obtain a catalase@ZIF-67 / silver phosphate-based composite material.

[0049] Example 2 The difference between Example 2 and Example 1 is that in Example 2, the catalase@ZIF-67 material in step (3) of Example 1 is replaced with the catalase@MIL-53 material, and the remaining steps and parameters are the same as those of Example 1. The specific steps are as follows: (1) Add 1.8 g of terephthalic acid to 100 mL of PBS buffer and mix well to obtain an organic ligand solution; add 0.2 g of catalase and 20 mg of polyvinyl pyrrolidone to the organic ligand solution, stir at 30°C and 200 rpm for 2 h to obtain a mixed solution; (2) Add 1 g of aluminum chloride hexahydrate to 100 mL of PBS buffer and mix well to obtain a metal source solution; add the mixed solution to the metal source solution and stir at 30°C and 200 rpm for 12 h, filter and wash the precipitate with deionized water for 3 times, and vacuum dry at -80°C for 12 h to obtain catalase @ MIL-53 material; the scanning electron microscopy image of the catalase @ MIL-53 material is shown in FIG. Figure 3 shown.

[0050] (3) Add 0.3 g of silver phosphate (Ag3PO4) to 100 mL of methanol, mix well to obtain a silver phosphate solution, add 1 g of the catalase@MIL-53 material of step (2), react at 30 ° C and 200 rpm for 12 h, filter and wash the precipitate with deionized water for 3 times, and vacuum dry at -80 ° C for 12 h to obtain a catalase@MIL-53 / silver phosphate-based composite material.

[0051] Example 3 The difference between Example 3 and Example 1 is that in Example 3, the catalase in step (1) of Example 1 is replaced by glucose oxidase of the same mass, and the remaining steps and parameters are the same as those of Example 1.

[0052] Example 4 The difference between Example 4 and Example 1 is that in Example 4, the amount of organic ligand added in step (1) of Example 1 is changed from 1.8 g to 2.5 g, and the remaining steps and parameters are the same as those of Example 1.

[0053] Example 5 The difference between Example 5 and Example 1 is that in Example 5, the amount of catalase added in Example 1 is changed from 0.2 g to 0.4 g, and the remaining steps and parameters are the same as in Example 1.

[0054] Example 6 The difference between Example 6 and Example 1 is that in Example 6, the amount of photocatalytic material Ag3PO4 added in Example 1 is changed from 0.3 g to 0.6 g, and the remaining steps and parameters are the same as in Example 1.

[0055] Table 1 Summary of differences in Examples 1-6 Example 7 (1) Add 2 g of 2-methylimidazole to 100 mL of PBS buffer and mix well to obtain an organic ligand solution; add 0.1 g of catalase and 20 mg of polyethylene glycol to the organic ligand solution, stir at 20°C and 300 rpm for 3 h to obtain a mixed solution; (2) Add 2 g of cobalt acetate to 80 mL of PBS buffer and mix well to obtain a metal source solution; add the mixed solution to the metal source solution and stir at 20 ° C and 300 rpm for 16 h, filter and wash the precipitate with deionized water for 3 times, and vacuum dry at -70 ° C for 10 h to obtain catalase @ ZIF-67 material; (3) Add 0.1 g of silver phosphate (Ag3PO4) to 40 mL of water, mix well to obtain a silver phosphate solution, add 1 g of the catalase@ZIF-67 material of step (2), react at 20°C and 300 rpm for 16 h, filter, wash the precipitate with deionized water three times, and vacuum dry at -70°C for 10 h to obtain a catalase@ZIF-67 / silver phosphate-based composite material.

[0056] Example 8 (1) Add 1 g of terephthalic acid to 50 mL of PBS buffer and mix well to obtain an organic ligand solution; add 0.2 g of glucose oxidase and 13.5 mg of polyvinyl alcohol to the organic ligand solution, stir at 40°C and 100 rpm for 1 h to obtain a mixed solution; (2) Add 0.4 g of aluminum nitrate nonahydrate to 30 mL of PBS buffer and mix well to obtain a metal source solution; add the mixed solution to the metal source solution and stir at 40°C and 100 rpm for 10 h, filter and wash the precipitate with deionized water for 3 times, and vacuum dry at -90°C for 16 h to obtain glucose oxidase@MIL-53 material; (3) Add 1 g of silver phosphate (Ag3PO4) to 100 mL of dimethyl sulfoxide, mix well to obtain a silver phosphate solution, add 1 g of the catalase @ MIL-53 material of step (2), react at 40 ° C and 100 rpm for 10 h, filter and wash the precipitate with deionized water for 3 times, and vacuum dry at -90 ° C for 16 h to obtain a glucose oxidase @ MIL-53 / silver phosphate-based composite material.

[0057] Comparative Example 1 The steps for preparing the catalase@ZIF-67 material without silver phosphate loading are as follows: (1) Add 1.8 g of 2-methylimidazole to 100 mL of PBS buffer and mix well to obtain an organic ligand solution; add 0.5 g of catalase and 20 mg of polyvinyl pyrrolidone to the organic ligand solution, stir at 30°C and 200 rpm for 2 h to mix well to obtain a mixed solution; (2) Add 1 g of cobalt nitrate to 100 mL of PBS buffer and mix well to obtain a metal source solution; add the mixed solution to the metal source solution and stir at 30 °C and 200 rpm for 12 h. After filtering, wash the precipitate with deionized water three times and vacuum dry it at -80 °C for 12 h to obtain catalase@ZIF-67 material.

[0058] The difference between Comparative Example 1 and Example 1 is that the catalase@ZIF-67 material in Comparative Example 1 is not loaded with silver phosphate, and the amount of catalase is correspondingly increased.

[0059] Comparative Example 2 The steps for preparing the ZIF-67 / silver phosphate-based material without immobilized enzymes are as follows: (1) Add 1.8 g of 2-methylimidazole to 100 mL of PBS buffer and mix well to obtain an organic ligand solution; add 20 mg of polyvinyl pyrrolidone to the organic ligand solution and stir at 30°C and 200 rpm for 2 h to obtain a mixed solution; (2) Add 1 g of cobalt nitrate to 100 mL of PBS buffer and mix well to obtain a metal source solution; add the mixed solution to the metal source solution and stir at 30°C and 200 rpm for 12 h, filter and wash the precipitate with deionized water three times, and vacuum dry at -80°C for 12 h to obtain ZIF-67 material; (3) Add 0.5 g of silver phosphate (Ag3PO4) to 100 mL of methanol, mix well to obtain a silver phosphate solution, add 1 g of the ZIF-67 material of step (2), react at 30 ° C and 200 rpm for 12 h, filter, wash the precipitate with deionized water three times, and vacuum dry at -80 ° C for 12 h to obtain a ZIF-67@silver phosphate-based composite material.

[0060] The difference between Comparative Example 2 and Example 1 is that the ZIF-67@silver phosphate-based composite material of Comparative Example 2 does not immobilize catalase, and the content of silver phosphate is correspondingly increased.

[0061] Comparative Example 3 The preparation of catalase@silver phosphate-based materials without MOFs is as follows: (1) Add 0.2 g of catalase and 20 mg of polyvinyl pyrrolidone into 100 mL of PBS buffer, stir at 30 °C and 200 rpm for 2 h to mix evenly to obtain a mixed solution; (2) Add 0.3 g of silver phosphate (Ag3PO4) to 100 mL of methanol and mix well to obtain a silver phosphate solution; add the silver phosphate solution to the mixed solution, stir at 30 °C and 200 rpm for 12 h, filter and wash the precipitate with deionized water for 3 times, and then vacuum dry at -80 °C for 12 h to obtain catalase@silver phosphate-based material.

[0062] Comparative Example 4: The 0.2 g of catalase in Example 1 was replaced with 0.2 g of lysozyme (CAS No. 12650-88-3), and the remaining steps and parameters remained unchanged to prepare a lysozyme@silver phosphate-based composite material.

[0063] Comparative Example 5 The ZIF-67 material in Example 1 is replaced by the ZIF-90 material, and the steps are as follows: (1) Add 1.8 g of 2-carboxymethylimidazole to 100 mL of PBS buffer and mix well to obtain an organic ligand solution; add 0.2 g of catalase and 20 mg of polyvinyl pyrrolidone to the organic ligand solution, stir at 30°C and 200 rpm for 2 h to mix well to obtain a mixed solution; (2) Add 1 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) to 100 mL of PBS buffer and mix well to obtain a metal source solution; add the mixed solution to the metal source solution and stir at 30°C and 200 rpm for 12 h, filter and wash the precipitate with deionized water three times, and vacuum dry at -80°C for 12 h to obtain catalase@ZIF-90 material; the scanning electron microscopy image of the catalase@ZIF-90 material is shown in FIG. Figure 4 shown.

[0064] (3) Add 0.3 g of silver phosphate (Ag3PO4) to 100 mL of methanol, mix well to obtain a silver phosphate solution, add 1 g of the catalase @ ZIF-90 material of step (2), react at 30 ° C and 200 rpm for 12 h, filter, wash the precipitate with deionized water three times, and vacuum dry at -80 ° C for 12 h to obtain a catalase @ ZIF-90 / silver phosphate-based composite material.

[0065] Comparative Example 6 The 0.3 g of silver phosphate in Example 1 was replaced with 0.3 g of titanium dioxide, and the remaining steps and parameters were the same as in Example 1.

[0066] Comparative Example 7 The dispersant in Example 1 was increased from 20 mg to 200 mg, and the remaining steps and parameters were the same as in Example 1.

[0067] Comparative Example 8 The 0.3 g of silver phosphate in Example 1 was replaced with 1.2 g of silver phosphate, and the remaining steps and parameters were the same as in Example 1.

[0068] Test Example 1 Antibacterial Effect Test objects: materials prepared in Examples 1-8 and Comparative Examples 1-8.

[0069] Test bacteria: Pseudomonas aeruginosa (ATCC 9027), from Guangdong Microbiological Analysis and Testing Center.

[0070] Test conditions: The initial concentration of Pseudomonas aeruginosa solution was 3×10 7 CFU / mL, the solution volume is 100mL, and the amount of material added is 0.48g / L. Test after visible light irradiation for 0.5h, 1h, 1.5h, and 2h. The bacterial concentration before and after the experiment was measured by plate counting method, and the test results were compared.

[0071] Table 2 Test results of different materials for removing Pseudomonas aeruginosa The test results of different materials for removing Pseudomonas aeruginosa are shown in Table 2. It can be seen that under the same test conditions, the sterilization rate of Examples 1-8 is as high as 100% within 2 hours.

[0072] The bactericidal effect of Example 1 is higher than that of Comparative Examples 1-3, indicating that silver phosphate, MOFs materials and biological enzymes can promote each other and improve the overall performance of the composite material. If one of the silver phosphate, MOFs materials and biological enzymes is missing, the antibacterial performance of the composite material will deteriorate. The bactericidal effect of Example 1 is much higher than that of Comparative Examples 4-6, indicating that in the present invention, the composite material needs to be under specific types of enzymes, MOFs and photocatalytic materials in order for the material to achieve a good bactericidal effect. In the present invention, the biological enzymes of the composite material are preferably catalase and glucose oxidase, MOFs are preferably ZIF-67 and MIL-53, and the photocatalytic material is preferably silver phosphate. The bactericidal effect of Example 1 is much higher than that of Comparative Examples 7 and 8, indicating that in the process of preparing the composite material, the amount of dispersant and silver phosphate added will affect the bactericidal performance of the final product. Excessive addition of dispersant will hinder the growth of MOFs crystals, reduce the porosity of the material, and change the surface properties and catalytic performance of the material, resulting in poor bactericidal performance of the final product. Adding too much silver phosphate can easily lead to a reduction in the specific surface area of ​​the final product. Too much silver phosphate will cover the bactericidal active sites, resulting in poor bactericidal effect of the final product.

[0073] Test Example 2: Effect of Degrading Antibiotics Test objects: materials prepared in Examples 1-8 and Comparative Examples 1-8.

[0074] Antibiotics tested: ampicillin, diclofenac sodium.

[0075] Test conditions: A 300W xenon lamp was used as the light source, and an ultraviolet cutoff filter (>420nm) was installed on the lamp to ensure that the light provided was only visible light. 10mg of the materials in Examples 1-8 and Comparative Examples 1-8 were added to 50mL of an aqueous solution containing ampicillin or diclofenac sodium (the concentrations of ampicillin and diclofenac sodium were both 20mg / L), and the mixed solution was magnetically stirred in the dark for 30 minutes to achieve adsorption-desorption equilibrium between the material and the pollutant. Then the light was turned on for irradiation. During the irradiation period, 1 ml of the reaction solution was taken every 10min and filtered through a 0.22 micron polyethersulfone (PES) filter membrane to obtain a supernatant. The remaining content of ampicillin or diclofenac sodium was measured using ultrahigh liquid chromatography (HPLC). The removal rate of ampicillin or diclofenac sodium was calculated by the original content and the remaining content of ampicillin or diclofenac sodium.

[0076] Table 3 Test results of degradation of ampicillin and diclofenac sodium by different materials It can be seen that under the same test conditions, the degradation effect of antibiotics in Example 1 is much higher than that in Comparative Examples 1-3, indicating that silver phosphate, MOFs materials and biological enzymes can promote each other and improve the overall performance of the composite material. If one of the silver phosphate, MOFs materials and biological enzymes is missing, the degradation performance of the composite material will deteriorate. The degradation effect of antibiotics in Example 1 is much higher than that in Comparative Examples 4-6, indicating that in the present invention, the composite material needs to be in the presence of specific types of enzymes, MOFs and photocatalytic materials in order for the material to achieve a good degradation effect of antibiotics. In the present invention, the biological enzymes of the composite material are preferably catalase and glucose oxidase, MOFs are preferably ZIF-67 and MIL-53, and the photocatalytic material is preferably silver phosphate. The degradation effect of antibiotics in Example 1 is much higher than that in Comparative Examples 7 and 8, indicating that in the process of preparing the composite material, the amount of dispersant and silver phosphate added will affect the degradation performance of the final product. Excessive addition of dispersant will hinder the growth of MOFs crystals, reduce the porosity of the material, and change the surface properties and catalytic properties of the material, making the degradation performance of the final product poor. Adding too much silver phosphate will result in a higher recombination rate of photogenerated electrons and hole pairs, resulting in low photocatalytic efficiency and poor antibiotic degradation effect of the final product.

[0077] Test Example 3 Recyclability Test Test object: Catalase@ZIF-67 / silver phosphate-based composite material of Example 1.

[0078] Test items: antibacterial effect (Pseudomonas aeruginosa, ATCC 9027), antibiotic degradation effect.

[0079] Test conditions: The test conditions for antibacterial effect are the same as those for test 1, and the test conditions for degradation of antibiotics are the same as those for test 2. After one test, centrifuge and wash with distilled water, take the precipitate and test it again, and repeat ten times.

[0080] Table 4 Example 1 Antibacterial and ampicillin degradation cycle performance test It can be seen from Table 4 that after 10 cycles of experiments, the catalase @ ZIF-67 / silver phosphate-based composite material of Example 1 still has a high antibacterial rate under 2 hours of illumination, and the ampicillin removal rate is also above 85%. Therefore, the bioenzyme @ MOFs / silver phosphate-based composite material of the present invention has strong repeatability in the photocatalytic system.

[0081] Test Example 4: Security Test Test object: Catalase@ZIF-67 / silver phosphate-based composite material of Example 1.

[0082] Test item: CCK-8 method to detect the toxicity of catalase @ ZIF-67 / silver phosphate composite materials to cells Test conditions: HeLa cells in the logarithmic growth phase were inoculated in a 96-well cell culture plate. After culturing for 24 hours, the cells were treated with 10 μg / mL H-DMEM medium containing 10% FBS. After 24 hours, 48 ​​hours, and 72 hours of treatment, CCK-8 reagent was added and cultured for 2-4 hours. Finally, the absorbance value was measured at a wavelength of 450 nm using an ELISA reader, and the cell survival rate was calculated to evaluate the toxicity of the material.

[0083] from Figure 5 It can be seen that at a low concentration (10 μg / mL), the cell survival rates at 24 hours, 48 ​​hours and 72 hours were 88.1%, 86.3% and 85.5%, respectively, showing a high cell survival rate. Therefore, the bioenzyme@MOFs / silver phosphate-based composite material of the present invention has good biocompatibility and is very safe and environmentally friendly in the process of water treatment.

[0084] Catalase and ZIF-67 or MIL-53 both have good biocompatibility, which is because in the bioenzyme@MOFs / silver phosphate-based composite material, ZIF-67 or MIL-53 as a carrier can slowly release the activity of catalase, preventing it from rapidly decomposing in the body, leading to local excessive oxygen concentration and oxidative stress. This slow release effect helps to reduce damage to normal cells while maintaining efficient bactericidal effects on bacteria. The composite material of the present invention has a certain targeting or selectivity through the combination of ZIF-67 or MIL-53 and silver phosphate, and can act more effectively on bacterial cells, while having less effect on normal cells. Silver phosphate (Ag3PO4) has strong photocatalytic activity and can produce reactive oxygen species (ROS) under light, thereby destroying bacterial cell membranes, proteins and DNA. However, the generation of these ROS may be controlled and is only effective for microorganisms on the surface of the contact material, while having little effect on normal cells. The silver ions in silver phosphate have a broad-spectrum antibacterial effect, but their release rate is relatively slow, so they will not cause high cytotoxicity while sterilizing. The low release rate of silver ions and the controlled release properties of the material make it less toxic to normal cells during the sterilization process.

[0085] The above test results show that the bio-enzyme@MOFs / silver phosphate-based composite material prepared by the present invention has beneficial antibacterial and degradation properties of antibiotics in water. It can simultaneously remove Pseudomonas aeruginosa, ampicillin and diclofenac sodium in wastewater and has excellent circulation performance and safety performance.

[0086] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a bioenzyme@MOFs / silver phosphate-based composite material, characterized in that The following steps are involved: (1) adding the biological enzyme and the dispersant to the organic ligand solution and mixing them evenly to obtain a mixed solution 1; (2) adding a metal source solution to the mixed solution 1, stirring for reaction, filtering, and drying the filter residue to obtain a bio-enzyme@MOFs material; (3) Adding the bio-enzyme@MOFs material to a silver phosphate solution, mixing and reacting, and drying the obtained solid to obtain a bio-enzyme@MOFs / silver phosphate-based composite material.

2. The method for preparing the bioenzyme@MOFs / silver phosphate-based composite material according to claim 1, characterized in that: The biological enzyme in step (1) includes at least one of catalase and glucose oxidase.

3. The method for preparing the bioenzyme@MOFs / silver phosphate-based composite material according to claim 1, characterized in that: The MOFs material in step (2) includes at least one of ZIF-67 nanoparticles and MIL-53 nanoparticles.

4. The method for preparing the bioenzyme@MOFs / silver phosphate-based composite material according to claim 1, characterized in that: The dispersant in step (1) comprises at least one of polyvinyl pyrrolidone, hexadecyltrimethylammonium bromide, polyethylene glycol and polyvinyl alcohol; In the organic ligand solution of step (1), the mass ratio of the organic ligand to the solvent is 1:(30-200); the organic ligand comprises at least one of 2-methylimidazole, benzimidazole, 2-ethylimidazole, terephthalic acid, and 1,4-cyclohexanedicarboxylic acid; the solvent comprises at least one of PBS buffer and water; The temperature for uniform mixing in step (1) is 20-40° C., and the time for uniform mixing is 1-3 hours.

5. The method for preparing the bioenzyme@MOFs / silver phosphate-based composite material according to claim 1, characterized in that: In the metal source solution of step (2), the mass ratio of the metal source to the solvent is 1:(30-200); the metal source comprises at least one of cobalt nitrate, cobalt chloride, cobalt acetate, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, and chromium sulfate; and the solvent comprises at least one of PBS buffer and water; The stirring reaction temperature in step (2) is 20-40° C., and the stirring reaction time is 10-16 h.

6. The method for preparing the bioenzyme@MOFs / silver phosphate-based composite material according to claim 1, characterized in that: In the silver phosphate solution of step (3), the mass ratio of silver phosphate to solvent is 1:(100-400); the solvent comprises at least one of ethanol, methanol, dimethyl sulfoxide, N,N-dimethylformamide, and water; The temperature of the mixed reaction in step (3) is 20-40° C., and the time of the mixed reaction is 10-16 hours.

7. The method for preparing the bioenzyme@MOFs / silver phosphate-based composite material according to claim 1, characterized in that: The mass ratio of the biological enzyme to the organic ligand in step (1) is 1:(4-20); the mass ratio of the biological enzyme to the dispersant in step (1) is (5-20):1; The mass ratio of the organic ligand in the organic ligand solution in step (1) to the metal source in the metal source solution in step (2) is (1-2.5):1; In step (3), the mass ratio of the bio-enzyme@MOFs material to the silver phosphate is 1:(0.1-1).

8. A bioenzyme@MOFs / silver phosphate-based composite material prepared according to the method according to any one of claims 1 to 7.

9. Use of the bioenzyme@MOFs / silver phosphate-based composite material according to claim 8 in water treatment.

10. The use of the bioenzyme@MOFs / silver phosphate-based composite material in water treatment according to claim 9, characterized in that The water body is a water body containing at least one of Pseudomonas aeruginosa, ampicillin and diclofenac sodium.

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