Bimetal MOFs composite material and preparation method and application thereof

Abstract

The invention belongs to the technical field of functional nano materials and antibiosis, and discloses a bimetallic MOFs composite material and a preparation method and application thereof. The preparation method of the composite material comprises the following steps: dissolving a copper source and a cerium source in water, adding an alkaline precipitant to form a double-metal hydroxide precipitate, and heating for reaction to obtain CuO-CeO2 nanoparticles; the preparation method comprises the following steps: dispersing CuO-CeO2 nanoparticles in a ZIF-8 precursor solution, stirring for reaction to obtain CuO-CeO2 ZIF-8 composite particles, dispersing the composite particles in water, adding a silver nitrate solution and a reducing agent, uniformly mixing, adjusting the pH value to 8.0-10.0, and stirring for reaction to obtain the bimetallic MOFs composite material. According to the bimetallic MOFs composite material disclosed by the invention, the silver nanoparticles and the bimetallic nano enzyme are introduced, so that a multiple synergistic antibacterial mechanism is formed, and excellent antibacterial and PPCPs pollutant degradation performance is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional nanomaterials and antibacterial technology, and particularly relates to a bimetallic MOFs composite material, a preparation method thereof, and an application thereof. Background Art

[0002] With the extensive use and abuse of antibiotics, the generation and spread of drug-resistant bacteria (such as superbugs) have become a major challenge in the global public health field. Traditional antibacterial agents usually rely on a single bactericidal mechanism, for example, by blocking bacterial metabolic pathways or destroying cell walls. However, this single mechanism gradually fails when facing drug-resistant strains, resulting in a significant decline in antibacterial efficacy. In addition, the performance of traditional antibacterial agents is easily limited in complex environments (such as high temperature, oxidative media), making it difficult to meet the diverse actual application requirements. The above problems have given rise to an urgent need for new multifunctional antibacterial materials, especially materials that can integrate multiple synergistic antibacterial mechanisms to effectively deal with drug-resistant strains and complex infection scenarios.

[0003] Metal-organic frameworks (MOFs) have shown great potential in the field of antibacterial materials due to their unique high specific surface area, good chemical stability, and adjustable structure. MOFs can not only serve as stable carriers for nanoparticles but also endow composite materials with stronger functionalization capabilities by regulating pore structures and surface chemical properties. For example, Chinese Patent Application CN201911375608.1 discloses a preparation method of a zinc oxide-metal organic framework composite antibacterial material, which grows ZnO NPs on the surface and within the pores of MOFs-Ln by an in-situ growth method to prepare a ZnO NPs@MOFs-Ln material with good antibacterial performance. Chinese Patent Application CN202211217688.X discloses a metal-organic framework nanocomposite, a preparation method thereof, and an application thereof, which loads 3,3′,5,5′-tetramethylbenzidine (TMB) and horseradish peroxidase (HPR) on the surface of a metal-organic framework (MOF) to form a metal-organic framework nanocomposite with antibacterial performance.

[0004] However, current MOF-based antibacterial materials still have many technical bottlenecks. For example, uneven distribution of functional components leads to insufficient utilization of active sites, and the material structure is prone to instability in complex environments, resulting in poor antibacterial performance of the obtained MOF antibacterial materials. Therefore, how to prepare MOFs composite materials with stable loading of functional components and efficient synergistic antibacterial effects through efficient design and preparation methods has become a key technical problem. Summary of the Invention

[0005] In order to overcome the above-mentioned disadvantages and deficiencies of the prior art, the primary object of the present invention is to provide a preparation method of a bimetallic MOFs composite material.

[0006] Another object of the present invention is to provide a bimetallic MOFs composite material prepared by the above method.

[0007] Another object of the present invention is to provide the application of the above bimetallic MOFs composite material in the preparation of antibacterial materials and sewage treatment.

[0008] The object of the present invention is achieved by the following scheme:

[0009] A preparation method of a bimetallic MOFs composite material includes the following steps:

[0010] (1) Dissolve a copper source and a cerium source in water, then add a basic precipitating agent to form a bimetallic hydroxide precipitate, and then obtain CuO-CeO 2 nanoparticles after heating reaction, washing and drying;

[0011] (2) Disperse the CuO-CeO 2 nanoparticles in a ZIF-8 precursor solution, stir and react, and after the reaction is completed, wash and dry to obtain CuO-CeO 2 @ZIF-8 composite particles;

[0012] (3) Disperse the CuO-CeO 2 @ZIF-8 composite particles in water, then add a silver nitrate solution and a reducing agent, mix evenly and adjust the pH to 8.0-10.0, stir and react, and after the reaction is completed, wash and dry to obtain a bimetallic MOFs composite material.

[0013] In step (1):

[0014] In some embodiments, the copper source includes at least one of copper nitrate trihydrate (Cu(NO 3 ) 2 ·3H 2 O), copper chloride (CuCl 2 ), copper sulfate (CuSO 4 ), copper acetate (Cu(CH 3 COO) 2 ).

[0015] In some embodiments, the cerium source includes at least one of cerium nitrate hexahydrate (Ce(NO 3 ) 3 ·6H 2 O), cerium chloride (CeCl 3 ), cerium sulfate (Ce 2 (SO 4 ) 3 ), cerium acetate (Ce(CH 3 COO) 3 ).

[0016] In some embodiments, the molar ratio of the copper element of the copper source to the cerium element of the cerium source is 1:1 - 1:5.

[0017] In some embodiments, the basic precipitating agent includes at least one of sodium hydroxide (NaOH) solution, potassium hydroxide (KOH) solution, ammonia water (NH 3 ·H 2 O), sodium carbonate (Na 2 CO 3 ) solution, with a concentration of 0.1 - 1 M and an addition amount of 5% - 20% of the total volume of the reaction solution.

[0018] In some embodiments, after adding the basic precipitating agent, the pH of the reaction solution can be adjusted to 8.0 - 10.5.

[0019] In some embodiments, in the heating reaction, the heating reaction time is 10 - 15 hours and the stirring temperature is 160 - 200 °C.

[0020] In some embodiments, the cleaning includes washing with a solvent, the solvent includes at least one of water and ethanol, and the number of cleaning times is 3 - 5 times.

[0021] In some embodiments, the drying temperature is 60 - 100 °C and the drying time is 6 - 12 hours.

[0022] In step (1) of the present invention, adding a basic precipitating agent is to form a double metal hydroxide precipitate. After the heating reaction, CuO - CeO 2 nanoparticles, that is, double metal nanozymes, can be obtained.

[0023] In step (2):

[0024] In some embodiments, the ZIF - 8 precursor solution includes a zinc salt, an organic framework, a dispersant, and a solvent.

[0025] In some embodiments, the zinc salt includes at least one of zinc nitrate hexahydrate (Zn(NO 3 ) 2 ·6H 2 O), zinc chloride (ZnCl 2 ), zinc acetate (Zn(CH 3 COO) 2 ), zinc sulfate (ZnSO 4 ), and the concentration of zinc element in the zinc salt in the ZIF - 8 precursor solution is 0.1 - 1.0 M.

[0026] In some embodiments, the organic framework includes at least one of 2-methylimidazole, 4,5-dimethylimidazole, benzimidazole, 1H-imidazole, and 2-ethylimidazole, and the concentration of the organic framework in the ZIF-8 precursor solution is 50-500 mg / L;

[0027] In some embodiments, the dispersant includes at least one of polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS), and polyethylene glycol (PEG), and the addition amount of the dispersant is 1%-10% of the mass of the zinc salt;

[0028] In some embodiments, the solvent includes at least one of ethanol, methanol, dimethyl sulfoxide (DMA), and N,N-dimethylformamide (DMF).

[0029] In some embodiments, the mass ratio of the CuO-CeO 2 nanoparticles to the total mass of the zinc salt, organic framework, and dispersant in the ZIF-8 precursor solution is 1:10 - 1:80;

[0030] In some embodiments, the dispersion includes ultrasonic-assisted dispersion, the power of the ultrasonic-assisted dispersion is 200-300 W, and the time is 15-30 minutes;

[0031] In some embodiments, during the stirring reaction, the stirring rate is 300-500 rpm, the temperature is 20-45 °C, and the time is 12-24 hours.

[0032] In some embodiments, after the reaction ends, it further includes a centrifugation operation. After centrifugation, the obtained solid is washed and dried to obtain CuO-CeO 2 @ZIF-8 composite particles.

[0033] In some embodiments, the washing includes washing with a solvent, the solvent includes at least one of water, ethanol, and methanol, and the number of washing times is 3-5 times.

[0034] In some embodiments, the drying temperature is 60-100 °C, and the drying time is 6-12 hours.

[0035] In step (2) of the present invention, the purpose is to synthesize ZIF-8 crystals while enabling the CuO-CeO 2 bimetallic nanoparticles to be uniformly wrapped by the ZIF-8 crystals, and finally form CuO-CeO 2 @ZIF-8 composite particles.

[0036] In step (3):

[0037] In some embodiments, the mass ratio of the CuO-CeO 2 @ZIF-8 composite particles to water is 1:50 - 1:200.

[0038] In some embodiments, the dispersion includes ultrasonic dispersion, with an ultrasonic power of 150 - 300 W, an ultrasonic time of 10 - 30 minutes, and an ultrasonic temperature of 20 - 35 °C.

[0039] In some embodiments, the concentration range of the silver nitrate (AgNO 3 ) solution is 0.01 - 0.1 M, and the mass ratio of silver ions to the CuO-CeO 2 @ZIF-8 composite particles is 1:10 - 1:50.

[0040] In some embodiments, the reducing agent includes at least one of dopamine (PDA), ascorbic acid (VC), and sodium hydroxide complex (such as NaBH 4 ), and the addition amount of the reducing agent satisfies that the concentration of the reducing agent in the uniformly mixed solution is 0.01 - 0.1 M.

[0041] In some embodiments, the pH adjustment refers to adding at least one of sodium hydroxide solution (0.01 - 0.1 M), ammonia water (0.5 - 2 M), and sodium carbonate solution (0.01 - 0.1 M) to adjust the pH.

[0042] In some embodiments, the stirring reaction rate is 200 - 500 rpm, the reaction time is 4 - 8 hours, and the stirring temperature is 25 - 40 °C.

[0043] In some embodiments, the cleaning includes washing with a solvent, the solvent includes at least one of water and ethanol, and the number of cleaning times is 3 - 5 times.

[0044] In some embodiments, the drying temperature is 60 - 100 °C, and the drying time is 6 - 12 hours.

[0045] The purpose of step (3) of the present invention is to in-situ reduce silver nanoparticles (AgNPs) on the surface of the CuO-CeO 2 @ZIF-8 composite particles, and finally obtain a bimetallic MOFs composite material with high antibacterial performance.

[0046] When preparing multi-component composite materials, functional nanoparticles are prone to aggregation, resulting in insufficient exposure of active sites and thus reducing the material performance. The present invention realizes the uniform distribution and effective loading of bimetallic nanozymes in the composite material by optimizing the coordination precipitation and in-situ reduction processes.

[0047] In a second aspect, the present invention provides a bimetallic MOFs composite material, which is prepared by the preparation method as described above.

[0048] In a third aspect, the present invention provides an application of the bimetallic MOFs composite material in the preparation of antibacterial materials and the treatment of sewage.

[0049] The bacteria species inhibited by the antibacterial material are preferably at least one of Pseudomonas aeruginosa drugs and methicillin-resistant Staphylococcus aureus.

[0050] The sewage is preferably sewage containing PPCPs pollutants, and more preferably sewage containing sulfamethoxazole (SMX).

[0051] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0052] (1) High antibacterial performance: Traditional single-functional antibacterial materials are difficult to cope with complex pathogenic bacteria infection scenarios. By organically integrating the peroxidase-like activity of bimetallic nanozymes (CuO-CeO 2 @ZIF-8 composite particles), the release function of antibacterial ions, and the protection and catalytic enhancement characteristics of the matrix material, a multiple synergistic antibacterial mechanism is formed to improve the overall performance. The bimetallic MOFs composite material of the present invention realizes excellent antibacterial performance by introducing silver nanoparticles (AgNPs) and bimetallic nanozymes (CuO and CeO 2 ). Silver nanoparticles have broad-spectrum antibacterial activity and can kill bacteria by destroying the bacterial cell wall and inhibiting cell metabolism; CuO and CeO 2 The bimetallic nanozyme catalyzes the generation of reactive oxygen species (such as hydroxyl radicals) in a hydrogen peroxide environment, further enhancing the antibacterial effect. The synergistic effect of the two makes the material show significant inhibitory effects on common Gram-positive bacteria, Gram-negative bacteria and some drug-resistant bacteria.

[0053] (2) Efficient degradation of PPCPs pollutants: In the bimetallic MOFs composite material of the present invention, the reactive oxygen species generated by the bimetallic nanozymes CuO and CeO 2 in a hydrogen peroxide environment can efficiently degrade the personal care product (PPCPs) pollutant - sulfamethoxazole (SMX), which is beneficial to the treatment of water pollution and ecological restoration, and is of great significance for further protecting the ecological water source and improving the water ecological environment.

[0054] (3) High efficiency and stability: Traditional antibacterial agents usually rely on a single bactericidal mechanism, making it difficult to effectively inhibit drug-resistant strains, and their performance is prone to failure in complex environments (such as high temperature, strongly oxidizing media), further limiting their practical applications. The purpose of this invention is to develop a bimetallic nanozyme composite material with multiple antibacterial mechanisms. Through the synergistic catalysis of the bimetallic nanozyme, combined with the stability and protective effect of the material structure, it can still maintain high antibacterial activity in complex environments, break through the resistance barrier of drug-resistant bacteria, and improve the applicability of the material in various practical scenarios. This composite material can still maintain good antibacterial performance and structural stability in complex environments (such as high temperature or high salt concentration). The porous structure of ZIF-8 provides a stable carrier, which not only provides excellent chemical stability, but also effectively prevents the aggregation of silver nanoparticles and the inactivation of the bimetallic nanozyme.

[0055] (4) Environmental friendliness: The preparation processes of many current nanomaterials rely on complex, expensive or environmentally unfriendly reagents and processes, restricting their large-scale applications. The preparation process of the composite material in this invention adopts green chemical methods, avoiding high temperature and high pressure conditions and the use of highly toxic reagents. Silver nanoparticles are prepared by in-situ reduction method, reducing the risk of silver ion loss and environmental pollution. At the same time, the composite material does not release harmful by-products during use and is suitable for scenarios with high environmental safety requirements, such as medical wastewater treatment and food packaging fields.

[0056] (5) Scalability and application potential: The preparation process of the composite material in this invention is simple. By adjusting the ratios of the bimetallic nanozyme, silver nanoparticles and ZIF-8 crystals, different antibacterial requirements can be met. The high antibacterial performance of the material makes it applicable to various scenarios, including antibacterial on the surface of medical devices, sewage treatment, food packaging, and antibacterial coatings for daily necessities. Its good performance and economy endow it with broad market prospects and application potential.

[0057] (6) High cost performance: By using bimetallic nanozymes to replace some precious metal antibacterial agents, this invention significantly reduces the material cost. At the same time, the introduction of the ZIF-8 matrix improves the utilization efficiency of silver nanoparticles and reduces the waste of antibacterial components. In addition, the bimetallic MOFs composite material in this invention can be reused. Compared with traditional antibacterial materials, this invention achieves a good balance between cost and performance and is an efficient and economical antibacterial solution. Description of the Drawings

[0058] Figure 1 Morphology diagram of CuO-CeO 2 nanoparticles in Example 1;

[0059] Figure 2 Morphology diagram of CuO-CeO 2@ZIF-8 composite particle morphology diagram;

[0060] Figure 3 For CuO-CeO in Example 1 2 @ZIF-8 / AgNPs composite material morphology diagram;

[0061] Figure 4 Scanning electron microscopy image of CuO metal nanozyme particles prepared in step (1) of Comparative Example 4;

[0062] Figure 5 For CeO prepared in step (1) of Comparative Example 5 2 Scanning electron microscopy image of metal nanozyme particles;

[0063] Figure 6 Scanning electron microscopy image of AgNPs material prepared in Comparative Example 7;

[0064] Figure 7 Morphology changes of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus before and after antibacterial treatment once in Example 1. a. Pseudomonas aeruginosa before antibacterial treatment; b. Pseudomonas aeruginosa after antibacterial treatment; c. Methicillin-resistant Staphylococcus aureus before antibacterial treatment; d. Methicillin-resistant Staphylococcus aureus after antibacterial treatment. Detailed implementation manners

[0065] The present invention will be further described in detail below with reference to examples and drawings, but the implementation manners of the present invention are not limited thereto. For those not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified for the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0066] Unless otherwise specified, the temperature in the examples and comparative examples refers to room temperature, and the room temperature is 20 - 40 °C.

[0067] Unless otherwise specified, the solvent of the solution in the examples and comparative examples is water.

[0068] Example 1

[0069] (1) Preparation of CuO-CeO 2 nanoparticles

[0070] Take 0.01 mol of copper nitrate trihydrate (Cu(NO 3 ) 2 ·3H 2 O) and 0.03 mol of cerium nitrate hexahydrate (Ce(NO 3 ) 3 ·6H 2(O) was dissolved in 100 mL of deionized water. It was stirred at a speed of 300 rpm for 30 minutes at 25 °C to form a uniform clear solution; then, 10 mL of 0.5 M sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH of the solution to 9.0 to form a precipitate of bimetallic hydroxide; after heating and reacting the precipitate at 180 °C for 12 hours, the precipitate was separated by centrifugation at 8000 rpm for 8 minutes, and washed 4 times with deionized water to remove residual ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain CuO-CeO 2 nanoparticles.

[0071] (2) Synthesis of ZIF-8 and encapsulation of CuO-CeO 2

[0072] 10 g of zinc nitrate hexahydrate (Zn(NO 3 )) 2 ·6H 2 O) and 20 g of 2-methylimidazole were added as ZIF-8 precursors to 50 mL of methanol, and then polyvinylpyrrolidone (PVP) equivalent to 5% of the mass of the zinc salt was added as a dispersant to prepare a ZIF-8 precursor solution. 0.5 g of the CuO-CeO 2 nanoparticles prepared above were dispersed in the ZIF-8 precursor solution, and ultrasonic-assisted dispersion was carried out for 20 minutes using an ultrasonic wave with a power of 250 W to ensure uniform distribution of the particles. Then, it was stirred and reacted at 400 rpm for 18 hours to uniformly encapsulate the CuO-CeO 2 nanoparticles with ZIF-8 crystals. After the reaction ended, the product was separated by centrifugation at 10000 rpm for 8 minutes, and washed 4 times with methanol to remove unreacted components. Finally, the product was dried at 80 °C for 8 hours to obtain CuO-CeO 2 @ZIF-8 composite particles.

[0073] (3) In-situ reduction of surface silver ions

[0074] 0.5 g of the obtained CuO-CeO 2 @ZIF-8 composite particles was dispersed in 50 mL of deionized water, and ultrasonic dispersion was carried out at 22 °C for 20 minutes using an ultrasonic wave with a power of 200 W. Subsequently, 4.62 mL of a 0.05 M silver nitrate (AgNO 3 ) solution was slowly added, so that silver ions reacted with CuO-CeO 2 ​The mass ratio of the @ZIF-8 composite particles was 1:20. Then, 0.75 g of ascorbic acid (VC) was added as a reducing agent, and the pH of the solution was adjusted to 9.0 with 0.05 M sodium hydroxide (NaOH) solution. The reaction was stirred at 30 °C at 300 rpm for 6 hours to in-situ reduce silver ions on the surface of the composite particles to form silver nanoparticles (AgNPs). After the reaction, the product was separated by centrifugation at 10,000 rpm for 8 minutes and washed 4 times with deionized water to remove residual silver ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain a bimetallic MOFs composite material (i.e., CuO-CeO 2 @ZIF-8 / AgNPs composite material).

[0075] The scanning electron microscope image of the CuO-CeO 2 nanoparticles prepared in step (1) of Example 1 is as shown in Figure 1 Figure , and the scanning electron microscope image of the CuO-CeO 2 @ZIF-8 composite particle material prepared in step (2) is as shown in Figure 2 Figure , and the scanning electron microscope image of the CuO-CeO 2 @ZIF-8 / AgNPs composite material prepared in step (3) is as shown in Figure 3 Figure .

[0076] Example 2

[0077] (1) Preparation of CuO-CeO 2 nanoparticles

[0078] CuO-CeO 2 nanoparticles were prepared according to the method of Example 1, with the only difference being that the copper source was changed from copper nitrate trihydrate (Cu(NO 3 ) 2 ·3H 2 O) to copper chloride (CuCl 2 ), and the dosage remained the same, i.e., 0.01 mol.

[0079] (2) Synthesis of ZIF-8 and encapsulation of CuO-CeO 2 were carried out exactly according to the method of Example 1.

[0080]

[0081] (3) In-situ reduction of surface silver ions

[0082]

[0083]

[0084] The difference between Example 2 and Example 1 is that the copper source was changed from copper nitrate trihydrate to copper chloride.

[0084] Example 3

[0085] (1) Preparation of CuO-CeO 2 nanoparticles

[0086] It is carried out completely according to the method of Example 1.

[0087] (2) Synthesis of ZIF-8 and encapsulation of CuO-CeO 2 encapsulation

[0088] It is carried out completely according to the method of Example 1.

[0089] (3) In-situ reduction of surface silver ions

[0090] According to the method of Example 1, the only difference is that the reducing agent is changed from ascorbic acid (VC) to sodium hydroxide complex (NaBH 4 ), and the addition amount is kept at 0.162 g, that is, 0.078 M.

[0091] Difference from Example 1: The reducing agent is changed from ascorbic acid to sodium hydroxide complex (NaBH 4 )

[0092] Example 4

[0093] (1) Preparation of CuO-CeO 2 nanoparticles

[0094] According to the method of Example 1, the only difference is that the molar ratio of copper element in the copper source to cerium element in the cerium source is changed from 1:3 to 1:2. The specific operation is to dissolve 0.01 mol of copper nitrate trihydrate and 0.02 mol of cerium nitrate hexahydrate in 100 mL of deionized water, and the remaining steps remain unchanged.

[0095] (2) Synthesis of ZIF-8 and encapsulation of CuO-CeO 2 encapsulation

[0096] It is carried out completely according to the method of Example 1.

[0097] (3) In-situ reduction of surface silver ions

[0098] It is carried out completely according to the method of Example 1.

[0099] Difference between Example 4 and Example 1: The molar ratio of copper element in the copper source to cerium element in the cerium source is changed from 1:3 to 1:2.

[0100] Example 5

[0101] (1) Preparation of CuO-CeO 2 nanoparticles

[0102] It was carried out according to the method of Example 1, and the only difference was that the alkaline precipitating agent was changed from 0.5 M sodium hydroxide (NaOH) solution to 0.5 M ammonia water (NH 3 ·H 2 O), and the addition amount and other conditions remained unchanged.

[0103] (2) Synthesis of ZIF-8 and encapsulation of CuO-CeO 2 was carried out exactly according to the method of Example 1.

[0104] It was carried out exactly according to the method of Example 1.

[0105] (3) In-situ reduction of surface silver ions

[0106] It was carried out exactly according to the method of Example 1.

[0107] The difference from Example 1: The alkaline precipitating agent was changed from sodium hydroxide solution to ammonia water.

[0108] Example 6

[0109] (1) Preparation of CuO-CeO 2 nanoparticles

[0110] It was carried out exactly according to the method of Example 1.

[0111] (2) Synthesis of ZIF-8 and encapsulation of CuO-CeO 2 was carried out exactly according to the method of Example 1.

[0112] It was carried out exactly according to the method of Example 1.

[0113] (3) In-situ reduction of surface silver ions

[0114] According to the method of Example 1, the only difference was that the mass ratio of silver ions to CuO-CeO 2 @ZIF-8 composite particles was adjusted from 1:20 to 1:15, that is, the amount of silver ions used increased, and the volume and concentration of the AgNO 3 solution were adjusted to achieve the new mass ratio. The solution was increased from 4.62 mL of 0.05 M silver nitrate (AgNO 3 ) solution to 6.18 mL of 0.05 M silver nitrate solution. Other steps remained unchanged.

[0115] The difference between Example 6 and Example 1: The mass ratio of silver ions to CuO-CeO 2 @ZIF-8 composite particles: was adjusted from 1:20 to 1:15.

[0116] Example 7

[0117] (1) Preparation of CuO-CeO 2 nanoparticles

[0118] It is carried out exactly according to the method of Example 1.

[0119] (2) Synthesis of ZIF-8 and encapsulation of CuO-CeO 2 encapsulation

[0120] According to the method of Example 1, the only difference is that the dispersant is changed from polyvinylpyrrolidone (PVP) to polyethylene glycol (PEG) (molecular weight 4000 Da), and the addition amount of the dispersant is maintained at 5% of the mass of the zinc salt.

[0121] (3) In-situ reduction of surface silver ions

[0122] It is carried out exactly according to the method of Example 1.

[0123] The difference between Example 7 and Example 1: The type of dispersant is changed from PVP to PEG.

[0124] Table 1 Summary of differences in Examples 1-7

[0125]

[0126] Comparative Example 1: CuO-CeO 2 nanoparticles

[0127] Synthesize CuO-CeO 2 nanoparticles without adding ZIF-8 and AgNPs.

[0128] Take 0.01 mol of copper nitrate trihydrate (Cu(NO 3 ) 2 ·3H 2 O) and 0.03 mol of cerium nitrate hexahydrate (Ce(NO 3 ) 3 ·6H 2 O), dissolve them in 100 mL of deionized water. Stir at a speed of 300 rpm for 30 minutes at 25 °C to form a uniform clear solution; then, slowly add 10 ml of 0.5 M sodium hydroxide (NaOH) solution to adjust the pH of the solution to 9.0 to form a precipitate of double metal hydroxide; after heating and reacting the precipitate at 180 °C for 12 hours, separate the precipitate by centrifuging at 8000 rpm for 8 minutes, and wash it 4 times with deionized water to remove residual ions and impurities. Finally, dry the product at 80 °C for 8 hours to obtain CuO-CeO 2 nanoparticles.

[0129] Comparative Example 2: CuO-CeO 2 / AgNPs composite material

[0130] Take 0.01 mol of copper(II) nitrate trihydrate (Cu(NO 3 ) 2 ·3H 2 O) and 0.03 mol of cerium(III) nitrate hexahydrate (Ce(NO 3 ) 3 ·6H 2 O), and dissolve them in 100 mL of deionized water. Stir at a speed of 300 rpm for 30 minutes at 25 °C to form a homogeneous clear solution; then, slowly add 10 mL of 0.5 M sodium hydroxide (NaOH) solution to adjust the pH of the solution to 9.0, forming a precipitate of bimetallic hydroxide. After heating the precipitate at 180 °C for 12 hours, separate the precipitate by centrifugation at 8000 rpm for 8 minutes, and wash it 4 times with deionized water to remove residual ions and impurities. Finally, dry the product at 80 °C for 8 hours to obtain CuO-CeO 2 nanoparticles.

[0131] Disperse 0.5 g of the obtained CuO-CeO 2 nanoparticles in 50 mL of deionized water, and disperse them for 20 minutes at 22 °C using ultrasonic waves with an ultrasonic power of 200 W. Subsequently, slowly add 4.62 mL of 0.05 M silver nitrate (AgNO 3 ) solution so that the mass ratio of silver ions to CuO-CeO 2 nanoparticles is 1:20. Then, add 0.75 g of ascorbic acid (VC) as a reducing agent, and adjust the pH of the solution to 9.0 with 0.05 M sodium hydroxide (NaOH) solution. Stir and react at 30 °C at 300 rpm for 6 hours to in-situ reduce silver ions on the surface of CuO-CeO 2 nanoparticles to form silver nanoparticles (AgNPs). After the reaction, separate the product by centrifugation at 10000 rpm for 8 minutes, and wash it 4 times with deionized water to remove residual silver ions and impurities. Finally, dry the product at 80 °C for 8 hours to obtain CuO-CeO 2 / AgNPs composite materials.

[0132] Comparative Example 3: CuO-CeO 2 @ZIF-8 composite materials

[0133] (1) Preparation of CuO-CeO 2 nanoparticles

[0134] Take 0.01 mol of copper(II) nitrate trihydrate (Cu(NO 3 ) 2 ·3H 2 O) and 0.03 mol of cerium(III) nitrate hexahydrate (Ce(NO 3 )3 ·6H 2 O), was dissolved in 100 mL of deionized water. It was stirred at a speed of 300 rpm for 30 minutes at 25 °C to form a uniform clear solution; then, 10 mL of 0.5 M sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH of the solution to 9.0, forming a precipitate of bimetallic hydroxide. After heating and reacting the precipitate at 180 °C for 12 hours, the precipitate was separated by centrifugation at 8000 rpm for 8 minutes, and washed 4 times with deionized water to remove residual ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain CuO-CeO 2 nanoparticles.

[0135] (2) Synthesis of ZIF-8 and encapsulation of CuO-CeO 2 of

[0136] 10 g of zinc nitrate hexahydrate (Zn(NO 3 ) 2 ·6H 2 O) and 20 g of 2-methylimidazole were added to 50 mL of methanol, and polyvinylpyrrolidone (PVP) equivalent to 5% of the mass of the zinc salt was added as a dispersant to prepare a ZIF-8 precursor solution. 0.5 g of the above-prepared CuO-CeO 2 nanoparticles were dispersed in the ZIF-8 precursor solution, and ultrasonic-assisted dispersion was carried out for 20 minutes using an ultrasonic wave with a power of 250 W to ensure uniform distribution of the particles. Then, it was stirred and reacted at 400 rpm for 18 hours to uniformly encapsulate the CuO-CeO 2 nanoparticles with ZIF-8 crystals. After the reaction, the product was separated by centrifugation at 10000 rpm for 8 minutes, and washed 4 times with methanol to remove unreacted components. Finally, the product was dried at 80 °C for 8 hours to obtain CuO-CeO 2 @ZIF-8 composite material.

[0137] Comparative Example 4: CuO@ZIF-8 / AgNPs composite material

[0138] (1) Preparation of CuO nanoparticles

[0139] Take 0.01 mol of copper nitrate trihydrate (Cu(NO 3 ) 2 ·3H 2O) was dissolved in 100 mL of deionized water. It was stirred at a speed of 300 rpm for 30 minutes at 25 °C to form a uniform clear solution; then, 10 mL of 0.5 M sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH of the solution to 9.0, forming a precipitate of metal hydroxide. After heating and reacting the precipitate at 180 °C for 12 hours, the precipitate was separated by centrifugation at 8000 rpm for 8 minutes, and washed 4 times with deionized water to remove residual ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain CuO nanoparticles.

[0140] (2) Synthesis of ZIF-8 and encapsulation of CuO

[0141] 10 g of zinc nitrate hexahydrate (Zn(NO 3 ) 2 ·6H 2 O) and 20 g of 2-methylimidazole were added as ZIF-8 precursors to 50 mL of methanol, and then polyvinylpyrrolidone (PVP) equivalent to 5% of the mass of the zinc salt was added as a dispersant to prepare a ZIF-8 precursor solution. 0.5 g of the above-prepared CuO nanoparticles were dispersed in the ZIF-8 precursor solution, and ultrasonic-assisted dispersion was carried out for 20 minutes using an ultrasonic wave with a power of 250 W to ensure uniform distribution of the particles. Then, the reaction was stirred at 400 rpm for 18 hours to uniformly encapsulate the CuO nanoparticles with ZIF-8 crystals. After the reaction, the product was separated by centrifugation at 10000 rpm for 8 minutes and washed 4 times with methanol to remove unreacted components. Finally, the product was dried at 80 °C for 8 hours to obtain CuO@ZIF-8 composite particles.

[0142] (3) In-situ reduction of surface silver ions

[0143] 0.5 g of the obtained CuO@ZIF-8 composite particles were dispersed in 50 mL of deionized water, and ultrasonic dispersion was carried out at 22 °C for 20 minutes using an ultrasonic wave with a power of 200 W. Subsequently, 4.62 mL of a 0.05 M silver nitrate (AgNO 3 ) solution was slowly added to make the mass ratio of silver ions to CuO@ZIF-8 composite particles 1:20. Then, 0.75 g of ascorbic acid (VC) was added as a reducing agent, and the pH of the solution was adjusted to 9.0 with 0.05 M sodium hydroxide (NaOH) solution. The reaction was stirred at 30 °C and 300 rpm for 6 hours to in-situ reduce silver ions on the surface of the CuO@ZIF-8 composite particles to form silver nanoparticles (AgNPs). After the reaction, the product was separated by centrifugation at 10000 rpm for 8 minutes and washed 4 times with deionized water to remove residual silver ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain CuO@ZIF-8 / AgNPs composite materials.

[0144] The scanning electron microscope image of the CuO nanoparticles prepared in step (1) of Comparative Example 4 is as follows Figure 4 shown

[0145] Comparative Example 5: CeO 2 @ZIF-8 / AgNPs composite material

[0146] (1) Preparation of CeO 2 nanoparticles

[0147] Take 0.01 mol of cerium nitrate hexahydrate (Ce(NO 3 )) 3 ·6H 2 O) and dissolve it in 100 mL of deionized water. Stir at a speed of 300 rpm for 30 minutes at 25 °C to form a uniform clear solution; then, slowly add 10 mL of 0.5 M sodium hydroxide (NaOH) solution to adjust the pH of the solution to 9.0 to form a metal hydroxide precipitate. After heating and reacting the precipitate at 180 °C for 12 hours, separate the precipitate by centrifuging at 8000 rpm for 8 minutes, and wash it 4 times with deionized water to remove residual ions and impurities. Finally, dry the product at 80 °C for 8 hours to obtain CeO 2 nanoparticles

[0148] (2) Synthesis of ZIF-8 and encapsulation of CeO 2

[0149] Add 10 g of zinc nitrate hexahydrate (Zn(NO 3 )) 2 ·6H 2 O) and 20 g of 2-methylimidazole as ZIF-8 precursors to 50 mL of methanol, then add 5% by mass of the zinc salt of polyvinylpyrrolidone (PVP) as a dispersant to obtain a ZIF-8 precursor solution. Disperse 0.5 g of the above-prepared CeO 2 nanoparticles in the ZIF-8 precursor solution, and use ultrasonic waves with a power of 250 W to assist in dispersing for 20 minutes to ensure uniform distribution of the particles. Then, stir and react at 400 rpm for 18 hours to uniformly encapsulate the CeO 2 particles with ZIF-8 crystals. After the reaction, centrifuge the product at 10000 rpm for 8 minutes to separate it, and wash it 4 times with methanol to remove unreacted components. Finally, dry the product at 80 °C for 8 hours to obtain CeO 2 @ZIF-8 composite particles

[0150] (3) In-situ reduction of surface silver ions

[0151] The obtained CeO 2 ​0.5 g of @ZIF-8 composite particles were dispersed in 50 mL of deionized water and dispersed for 20 minutes at 22 °C using ultrasonic waves with an ultrasonic power of 200 W. Subsequently, 4.62 mL of a 0.05 M silver nitrate (AgNO 3 ) solution was slowly added so that the mass ratio of silver ions to CeO 2 @ZIF-8 composite particles was 1:20. Then, 0.75 g of ascorbic acid (VC) was added as a reducing agent, and a 0.05 M sodium hydroxide (NaOH) solution was added to adjust the pH of the solution to 9.0. The reaction was stirred at 300 rpm at 30 °C for 6 hours to in-situ reduce silver ions to form silver nanoparticles (AgNPs) on the surface of the CeO 2 @ZIF-8 composite particles. After the reaction, the product was separated by centrifugation at 10,000 rpm for 8 minutes and washed 4 times with deionized water to remove residual silver ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain CeO 2 @ZIF-8 / AgNPs composite material.

[0152] The scanning electron microscope image of the CeO 2 nanoparticles prepared in step (1) of Comparative Example 5 is as shown in Figure 5 Figure.

[0153] Comparative Example 6: ZIF-8 / AgNPs composite material

[0154] (1) Synthesis of ZIF-8

[0155] 10 g of zinc nitrate hexahydrate (Zn(NO 3 ) 2 ·6H 2 O) and 20 g of 2-methylimidazole were added to 50 ml of methanol, and polyvinylpyrrolidone (PVP) equivalent to 5% of the mass of the zinc salt was added as a dispersant to prepare a ZIF-8 precursor solution. Ultrasonic waves with an ultrasonic power of 250 W were used for assisted dispersion for 20 minutes to ensure uniform distribution of the particles. Then, the reaction was stirred at 400 rpm for 18 hours. After the reaction, the product was separated by centrifugation at 10,000 rpm for 8 minutes and washed 4 times with methanol to remove unreacted components. Finally, the product was dried at 80 °C for 8 hours to obtain ZIF-8 particles.

[0156] (2) In-situ reduction of surface silver ions

[0157] 0.5 g of the obtained ZIF-8 particles were dispersed in 50 mL of deionized water and dispersed for 20 minutes at 22 °C using ultrasonic waves with an ultrasonic power of 200 W. Subsequently, 4.62 mL of a 0.05 M silver nitrate (AgNO 3) A solution was prepared such that the mass ratio of silver ions to ZIF-8 particles was 1:20. Then, 0.75 g of ascorbic acid (VC) was added as a reducing agent, and a 0.05 M sodium hydroxide (NaOH) solution was added to adjust the pH of the solution to 9.0. The reaction was stirred at 300 rpm at 30 °C for 6 hours to in-situ reduce silver ions on the surface of ZIF-8 particles to form silver nanoparticles (AgNPs). After the reaction, the product was separated by centrifugation at 10000 rpm for 8 minutes and washed 4 times with deionized water to remove residual silver ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain the ZIF-8 / AgNPs composite material.

[0158] Comparative Example 7: AgNPs material

[0159] Take 4.62 mL of a 0.05 M silver nitrate (AgNO 3 ) solution, then add 0.75 g of ascorbic acid (VC) as a reducing agent, and a 0.05 M sodium hydroxide (NaOH) solution is added to adjust the pH of the solution to 9.0. The reaction is stirred at 300 rpm at 30 °C for 6 hours to reduce silver ions to form silver nanoparticles (AgNPs). After the reaction, the product is separated by centrifugation at 10000 rpm for 8 minutes and washed 4 times with deionized water to remove residual silver ions and impurities. Finally, the product is dried at 80 °C for 8 hours to obtain the AgNPs material.

[0160] The scanning electron microscope image of the AgNPs material prepared in Comparative Example 7 is as Figure 6 shown.

[0161] Comparative Example 8: ZIF-8 material

[0162] 10 g of zinc nitrate hexahydrate (Zn(NO 3 ) 2 ·6H 2 O) and 20 g of 2-methylimidazole were added to 50 ml of methanol, and polyvinylpyrrolidone (PVP) equivalent to 5% of the mass of the zinc salt was added as a dispersant to prepare a ZIF-8 precursor solution. Ultrasonic-assisted dispersion was carried out at a ultrasonic power of 250 W for 20 minutes to ensure uniform distribution of the particles. Then, the reaction was stirred at 400 rpm for 18 hours. After the reaction, the product was separated by centrifugation at 10000 rpm for 8 minutes and washed 4 times with methanol to remove unreacted components. Finally, the product was dried at 80 °C for 8 hours to obtain the ZIF-8 material.

[0163] Comparative Example 9: NiO-CuO@ZIF-8 / AgNPs composite material

[0164] (1) Preparation of NiO-CuO nanoparticles

[0165] Take 0.01 mol of copper nitrate trihydrate (Cu(NO 3 ) 2 ·3H 2 O) and 0.03 mol of nickel nitrate hexahydrate (Ni(NO 3 ) 2 ·6H 2 O), and dissolve them in 100 mL of deionized water. Stir at a speed of 300 rpm for 30 minutes at 25 °C to form a homogeneous clear solution; then, slowly add 10 mL of 0.5 M sodium hydroxide (NaOH) solution to adjust the pH of the solution to 9.0 to form a precipitate of bimetallic hydroxide. After heating the precipitate at 180 °C for 12 hours, separate the precipitate by centrifuging at 8000 rpm for 8 minutes, and wash it 4 times with deionized water to remove residual ions and impurities. Finally, dry the product at 80 °C for 8 hours to obtain NiO-CuO nanoparticles.

[0166] (2) Synthesis of ZIF-8 and encapsulation of NiO-CuO

[0167] Completely follow the method of Example 1, and the only difference is that the CuO-CeO 2 nanoparticles in Example 1 are replaced with NiO-CuO nanoparticles.

[0168] (3) In-situ reduction of surface silver ions

[0169] Completely follow the method of Example 1.

[0170] In Comparative Example 9, the CuO-CeO 2 nanoparticles are replaced with NiO-CuO nanoparticles.

[0171] Comparative Example 10: CuO-CeO 2 @MOF-5 / AgNPs composite

[0172] (1) Preparation of CuO-CeO 2 nanoparticles

[0173] Completely follow the method of Example 1.

[0174] (2) Synthesis of MOF-5 and encapsulation of CuO-CeO 2

[0175] Completely follow the method of Example 1, and the only difference is that 20 g of 2-methylimidazole in the precursor solution of Example 1 is replaced with 20 g of phthalic acid (BDC), and other steps remain unchanged.

[0176] (3) In-situ reduction of surface silver ions

[0177] It is carried out exactly according to the method of Example 1.

[0178] In Comparative Example 10, ZIF-8 is replaced with MOF-5.

[0179] Comparative Example 11: CuO-CeO 2 @ZIF-8 / FeNPs composite

[0180] (1) Preparation of CuO-CeO 2 nanoparticles

[0181] It is carried out exactly according to the method of Example 1.

[0182] (2) Synthesis of ZIF-8 and encapsulation of CuO-CeO 2

[0183] It is carried out exactly according to the method of Example 1.

[0184] (3) In-situ reduction of surface iron ions

[0185] It is carried out exactly according to Example 1. The only difference is that 4.62 mL of a 0.05 M silver nitrate (AgNO 3 ) solution in Example 1 is replaced with 4.62 mL of a 0.05 M iron nitrate (Fe(NO 3 ) 3 ) solution, and other steps are the same as in Example 1.

[0186] In Comparative Example 11, silver nanoparticles are replaced with iron nanoparticles.

[0187] Test Example 1 Antibacterial effect

[0188] Test objects: Different materials prepared in Examples 1-7 and Comparative Examples 1-11.

[0189] Test bacteria: Pseudomonas aeruginosa (ATCC 15442), Methicillin-resistant Staphylococcus aureus (ATCC43300).

[0190] Test conditions: The initial concentrations of Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus bacterial solutions are both 3×10 7 CFU / mL, the volume of the bacterial solution is 50 ml, and the dosage of the sample material is 0.4 g / L. The bacterial concentrations before and after the experiment are obtained by the plate counting method, and the test results are compared.

[0191] Table 2 Test results of different materials for removing Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus

[0192]

[0193] According to the above experimental data and​Figure 7 As shown, the comparison between the examples and the comparative examples clearly shows that the CuO-CeO of our present invention 2 @ZIF-8 / AgNPs composite material shows significant advantages in the field of antibacterial. The experimental results show that the antibacterial rate of this composite material against Pseudomonas aeruginosa in Example 1 is as high as 99%, and the antibacterial effect against methicillin-resistant Staphylococcus aureus also reaches 97%. In contrast, Comparative Example 1 (CuO-CeO 2 nanoparticles) only shows antibacterial rates of 55.2% and 50.3%, which are significantly lower than the performance of Example 1. In addition, the antibacterial rates of Comparative Example 2 (CuO-CeO 2 / AgNPs composite material) are 74.9% and 71.6%, which are also much lower than those of Example 1, further proving that the synergistic effect of each component in the composite material is crucial for the antibacterial effect. The experimental results also show that before and after the antibacterial experiment, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus have obvious mineralization and rupture (as Figure 7 shown), further verifying the excellent antibacterial performance of this material.

[0194] Example 1 (using the synergistic effect of ZIF-8 support material and silver nanoparticles) shows the optimal antibacterial effect and material stability. Changing the copper source (Example 2) and the reducing agent (Example 3) will affect the solubility, reactivity of metal ions, and the generation rate and uniformity of silver nanoparticles, resulting in a decrease in the antibacterial effect. Adjusting the molar ratio of copper element to cerium element (Example 4) and changing the alkaline precipitating agent (Example 5) have an impact on the antibacterial effect, but still maintain a relatively high effect (greater than 90%). Changing the dispersant (Example 7) affects the dispersibility and stability of the material, resulting in a decrease in the antibacterial effect. Although the silver nanoparticle content was increased in Example 6, the antibacterial effect is still lower than that of Example 1. The reason is that excessive silver nanoparticles may lead to excessive aggregation of silver, uneven or excessive release of silver ions, and changes in the material structure, thus reducing the antibacterial effect. An appropriate amount of silver nanoparticles can exert the best antibacterial effect, while too much may bring side effects. Generally speaking, the synergistic effect of ZIF-8 and silver nanoparticles, as well as the appropriate reducing agent and copper-cerium ratio, are the key factors to improve the antibacterial effect.

[0195] The above results fully prove the excellent effect of this composite material against two typical pathogenic bacteria. In contrast, Comparative Example 1 (only CuO-CeO 2 nanoparticles) and other control groups show significantly lower antibacterial effects, indicating that the single catalyst lacks sufficient antibacterial activity. Although silver nanoparticles or ZIF-8 were added in Comparative Examples 2, 3, 4, and 5 in the composite material, due to the lack of reasonable synergistic effects, the antibacterial effects are still lower than those of Example 1. Especially in Comparative Example 2, CuO-CeO 2The antibacterial effects of the systems combining nanoparticles with AgNPs are only 74.9% and 71.6% respectively. This is mainly because without the support of ZIF-8, the stability and dispersibility of the materials are poor, thus reducing their antibacterial performance. In Comparative Example 4 and Comparative Example 5, after removing CeO 2 or CuO, the antibacterial effects against Pseudomonas aeruginosa decreased to 60.7% and 61.2%, and the antibacterial effects against methicillin-resistant Staphylococcus aureus decreased to 56.5% and 57.9%, further proving the synergistic effect of the bimetallic nanozyme in the antibacterial process.

[0196] In Comparative Example 8, the antibacterial rates of using only ZIF-8 are extremely low (4.2% and 3.7%), indicating that ZIF-8 itself has a weak antibacterial effect on the tested strains, and its main role is to act as a carrier and structural support. In Comparative Example 9 (NiO-CuO@ZIF-8 / AgNPs) and Comparative Example 11 (CuO-CeO 2 @ZIF-8 / FeNPs), the antibacterial rates are lower than those of the main example samples, indicating that adding other metal oxides (such as NiO) and other metal nanoparticles (such as FeNPs) cannot effectively improve the antibacterial performance, and may even be slightly inhibited due to the interaction between metals. The antibacterial rates of Comparative Example 10 (CuO-CeO 2 @MOF-5 / AgNPs) are 72.1% and 69.8%. Compared with the sample of Example 1 using ZIF-8, the antibacterial effect has decreased, further proving that ZIF-8 has a better antibacterial synergistic effect in this composite material.

[0197] In summary, our invention greatly enhances the antibacterial effect through multiple synergistic mechanisms (including bimetallic catalysis, silver ion release, ZIF-8 support, and an efficient reduction process), and can still maintain an antibacterial rate higher than 90% under different experimental conditions. This significant advantage indicates that the CuO-CeO 2 @ZIF-8 / AgNPs composite material has great application potential in the antibacterial field, and can effectively combat common pathogenic bacteria such as Escherichia coli and Staphylococcus aureus. This material not only has good stability, but also through reasonable component design, enables it to have strong industrial application prospects and is suitable for multiple fields such as medical devices, sewage treatment, and food packaging.

[0198] Test Example 2 Safety Test

[0199] Test Object: The material of Example 1 (CuO-CeO 2 @ZIF-8 / AgNPs).

[0200] Test Items: Detect the cytotoxicity of the composite material to cells by the CCK-8 method

[0201] Test conditions:

[0202] Using L929 fibroblasts as a model, inoculate them in a 96-well plate at a density of 10 5 cells / well, and place them in an incubator at 37 °C and 5% CO 2 for 24 hours. Aspirate and discard the culture medium. Add culture medium to the blank control group, and add test samples with different concentrations to the test substance group. After culturing for 24 h, take them out. Set three replicates for each concentration. After treatment for 24 hours, add 10 μL of CCK-8 reagent to each well and continue to incubate for 2 hours. Measure the OD value at a wavelength of 450 nm using an enzyme-linked immunosorbent assay (ELISA) reader, and calculate the cell survival rate using this value.

[0203] Table 3 Cell survival rates of the composite material in Example 1 at concentrations of 10, 50, and 100 μg / mL

[0204]

[0205]

[0206] According to the experimental data, the CuO-CeO 2 @ZIF-8 / AgNPs material shows good biocompatibility with L929 cells at different concentrations. At a concentration of 10 μg / mL, the cell survival rate is 97%, close to 100%, and almost no obvious toxic effects on the cells are caused, indicating that the material has very good biocompatibility at low concentrations and is suitable for low-dose biomedical applications. As the concentration increases to 50 μg / mL, the cell survival rate slightly decreases to 93%, still remaining at a high level, indicating that the material has very little impact on cells at medium concentrations and has good safety. At a concentration of 100 μg / mL, the cell survival rate decreases to 84%. Although it has decreased, it still meets the safety standards of biomaterials. Generally speaking, the CuO-CeO 2 @ZIF-8 / AgNPs material has low toxicity to L929 cells in the concentration range of 10-100 μg / mL, indicating its good biocompatibility at these concentrations and suitability for various biomedical fields, especially as a carrier material or antibacterial material.

[0207] Test Example 3: Degradation test of PPCPs pollutants

[0208] my country is a large agricultural country with a large number of livestock and poultry breeding. In order to treat and prevent infectious diseases of livestock and poultry or promote their growth, antibiotics and fungicides are usually added to feed, resulting in a large amount of personal care products (PPCPs) pollutants in breeding wastewater. Studies have shown that the ecotoxicity of residual PPCPs in the environment is diverse, and they are significantly enriched in organisms and the human body, so they pose a potential threat to the ecological environment and human health. This test uses sulfamethoxazole (SMX), a representative of PPCPs, as the target pollutant to explore the effect of bimetallic MOFs composite materials in degrading PPCPs pollutants.

[0209] During the experiment, 10 mg of the material to be tested was added to 50 ml of sulfamethoxazole solution containing 5 mg / L of antibiotics, and stirred at a constant rate for 30 minutes using a magnetic stirrer in a dark environment to achieve adsorption-desorption equilibrium between the material and the antibiotic. Subsequently, 10 μL of 0.6 wt% hydrogen peroxide solution was added and continued to stir. After 2 hours, 1 ml of the reaction solution sample was collected and filtered through a 0.22 μm polyethersulfone (PES) filter membrane. The residual concentration of antibiotics in the filtered supernatant was quantitatively analyzed by ultra-high liquid chromatography (HPLC), and the degradation rate of antibiotics by each material was calculated. The antibiotic adsorption capacity and degradation efficiency of different materials under hydrogen peroxide conditions were evaluated, so as to determine the potential effect of the material in practical applications.

[0210] Table 4 Test results of antibiotic degradation by different materials

[0211]

[0212]

[0213] Example 1 shows that the degradation rate of sulfamethoxazole (SMX) reaches 92.30%, demonstrating that CuO-CeO 2 @ZIF-8 / AgNPs composite material has high efficiency in catalytic degradation. This result shows that CuO, CeO 2 The synergistic effect of ZIF-8 and AgNPs played a key role in the degradation reaction. In contrast, although the degradation rates of other examples decreased slightly, they generally remained at a high level (88.50%-91.50%), indicating that optimizing different factors (such as copper source, reducing agent, silver ion concentration, etc.) has a certain effect on improving the degradation effect.

[0214] When comparing Example 2 and Example 3, we can see that the change of copper source (copper nitrate replaced by copper chloride) and the different choice of reducing agent (ascorbic acid and sodium hydroxide complex) have a certain impact on the degradation rate. Although these changes slightly reduce the catalytic performance, the degradation rate is still higher than that of general catalysts, indicating that the basic catalytic performance of the material remains good.

[0215] In Examples 4 and 5, the changes in the composition ratio and the precipitating agent affected the catalytic effect. Adjusting the molar ratio of Cu:Ce and using different precipitating agents changed the structure of the composite material and the distribution of catalytic sites, resulting in changes in the catalytic effect and a slight decrease in the degradation efficiency. Generally, however, the degradation rates of all examples were still relatively high, showing strong catalytic stability and potential.

[0216] Increasing the silver content in Example 6 brought the degradation rate to 91.50%, close to the benchmark level, indicating that silver nanoparticles have a promoting effect on the catalytic reaction, especially in terms of photocatalysis and silver ion release. However, excessive AgNPs may lead to the coverage of catalytic sites, resulting in a decrease in catalytic performance and failure to further improve the degradation effect.

[0217] In Example 7, using PEG as a dispersant improved the dispersibility of the material, and the degradation rate was 89.80%. Although it increased, it did not reach the expected performance improvement. This indicates that the dispersant has limited improvement on the catalytic effect, and its main role lies in the stability and dispersibility of the material.

[0218] The control group (Comparative Examples 1-11) showed that all samples without the CuO-CeO 2 @ZIF-8 / AgNPs composite material had generally low degradation rates. In particular, the degradation rate of Comparative Example 8 was only 7.40%. This result verified the high efficiency and unique role of the CuO-CeO 2 @ZIF-8 / AgNPs composite material in the degradation of sulfamethoxazole. Comparative Examples 4 and 5 (65.10% and 67.30% respectively) showed the inefficient performance when there was a lack of synergy in a single catalytic component (such as CuO or CeO 2 ), further emphasizing the promotion of the catalytic effect by the synergy of different components in the composite material.

[0219] For other comparative examples (such as Comparative Examples 2, 3, and 4), although the degradation rates were low, they also showed the effectiveness of certain components in the material (such as ZIF-8 and AgNPs). For example, Comparative Example 2 (75.60%) and Comparative Example 3 (68.90%) showed the promoting effect of the introduction of AgNPs on the catalytic performance, while Comparative Example 4 (65.10%) reflected that without CeO 2 , the synergistic effect of metal nanoparticles (i.e., metal nanoenzymes) and ZIF-8 could not be fully demonstrated.

[0220] In addition, the degradation rates of Comparative Example 9 and Comparative Example 10 (62.50% and 78.00%) are relatively high, which may be due to certain specific conditions playing a stronger role in these materials, but still cannot match the effects of the composite materials in the examples. Generally speaking, CuO-CeO 2 @ZIF-8 / AgNPs composite materials showed significant catalytic performance in the reaction of degrading sulfamethoxazole, and each component (CuO, CeO 2 , ZIF-8, AgNPs) in the composite materials greatly improved the catalytic effect through synergistic effects. In contrast, the catalytic effects of using CuO, CeO 2 , ZIF-8 or AgNPs alone were significantly lower than those of the composite materials, demonstrating the overall effectiveness of the composite materials. Although adjusting different material compositions (such as copper source, reducing agent, silver content, etc.) can optimize the catalytic performance, the increase beyond certain parameters may lead to the saturation of the effectiveness and fail to significantly improve the catalytic effect. Finally, the best catalytic effects in the examples, especially in terms of the silver content and the catalyst ratio, demonstrated the high potential and innovation of this material in catalytic degradation.

[0221] Test Example 4 Recyclability Test

[0222] Test object: The material of Example 1 (CuO-CeO 2 @ZIF-8 / AgNPs).

[0223] Test items: Antibacterial effect, degradation antibiotic recycling performance test.

[0224] Test conditions:

[0225] The test conditions for the antibacterial effect are the same as those in Test 1, and the test conditions for the degradation antibiotic effect are the same as those in Test Example 3. After each test, centrifuge and wash with distilled water, take the precipitate particles and test again, for ten cycles.

[0226] Table 5 Antibacterial and Degradation Antibiotic Recycling Performance Test of Example 1

[0227]

[0228] CuO-CeO 2After ten cycles of use, the antibacterial effect of the @ZIF-8 / AgNPs material still remains at a high level. Although the bactericidal rate and the antibiotic degradation rate have decreased, with the bactericidal rate of Pseudomonas aeruginosa decreasing from 99.3% to 87.7%, that of methicillin-resistant Staphylococcus aureus decreasing from 97.8% to 83.5%, and the degradation rate of sulfamethoxazole decreasing from 92.30% to 86.3%, it still exhibits strong reusability. The reason for the decrease in effect may be the reduction in silver ion release and the loss of surface active components of the material. However, the material still maintains a high antibacterial rate and antibiotic degradation efficiency, demonstrating its long-term effectiveness and stability in practical applications and making it suitable for continued use in environments with multiple uses.

[0229] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for preparing a bimetallic MOFs composite material, characterized in that The following steps are involved: (1) dissolving a copper source and a cerium source in water, then adding an alkaline precipitant to form a double metal hydroxide precipitate, heating for reaction, washing and drying to obtain CuO-CeO2 nanoparticles; (2) dispersing the CuO-CeO2 nanoparticles in a ZIF-8 precursor solution, stirring for reaction, and washing and drying after the reaction to obtain CuO-CeO2@ZIF-8 composite particles; (3) Dispersing the CuO-CeO2@ZIF-8 composite particles in water, then adding silver nitrate solution and a reducing agent, mixing evenly, adjusting the pH to 8.0-10.0, stirring for reaction, and washing and drying after the reaction to obtain a bimetallic MOFs composite material.

2. The method for preparing the bimetallic MOFs composite material according to claim 1, characterized in that: In step (1): The copper source includes at least one of copper nitrate trihydrate, copper chloride, copper sulfate, and copper acetate; The cerium source includes at least one of cerium nitrate hexahydrate, cerium chloride, cerium sulfate, and cerium acetate; The molar ratio of the copper element of the copper source to the cerium element of the cerium source is 1:1-1:5; The alkaline precipitant includes at least one of sodium hydroxide solution, potassium hydroxide solution, ammonia water, and sodium carbonate solution, with a concentration of 0.1-1M; After the alkaline precipitant is added, the pH of the reaction solution is adjusted to 8.0-10.5; In the heating reaction, the heating reaction time is 10-15 hours and the stirring temperature is 160-200°C.

3. The method for preparing the bimetallic MOFs composite material according to claim 1, characterized in that: In step (2): The ZIF-8 precursor solution includes zinc salt, organic framework, dispersant and solvent; The zinc salt includes at least one of zinc nitrate hexahydrate, zinc chloride, zinc acetate, and zinc sulfate, and the concentration of the zinc element in the zinc salt in the ZIF-8 precursor solution is 0.1-1.0M; The organic skeleton comprises at least one of 2-methylimidazole, 4,5-dimethylimidazole, benzimidazole, 1H-imidazole, and 2-ethylimidazole, and the concentration of the organic skeleton in the ZIF-8 precursor solution is 50-500 mg / L; The dispersant includes at least one of polyvinyl pyrrolidone, sodium lauryl sulfate and polyethylene glycol, and the added amount of the dispersant is 1%-10% of the mass of the zinc salt; The solvent includes at least one of ethanol, methanol, dimethylsulfenamide and N,N-dimethylformamide.

4. The method for preparing the bimetallic MOFs composite material according to claim 1, characterized in that: In step (2): The ratio of the mass of the CuO-CeO2 nanoparticles to the total mass of the zinc salt, the organic framework, and the dispersant in the ZIF-8 precursor solution is 1:10-1:80; The dispersion includes ultrasonic assisted dispersion, the power of the ultrasonic assisted dispersion is 200-300W, and the time is 15-30 minutes; During the stirring reaction, the stirring rate is 300-500 rpm, the temperature is 20-45° C., and the time is 12-24 hours.

5. The method for preparing the bimetallic MOFs composite material according to claim 1, characterized in that: In step (3): The mass ratio of the CuO-CeO2@ZIF-8 composite particles to water is 1:50-1:200; The concentration range of the silver nitrate solution is 0.01-0.1M, and the mass ratio of silver ions to the CuO-CeO2@ZIF-8 composite particles is 1:10-1:50; The reducing agent comprises at least one of dopamine, ascorbic acid and sodium hydroxide complex, and the amount of the reducing agent added satisfies that the concentration of the reducing agent in the mixed solution is 0.01-0.1M; The pH adjustment refers to adding at least one of sodium hydroxide solution, ammonia water, and sodium carbonate solution to adjust the pH; The stirring reaction speed is 200-500 rpm, the reaction time is 4-8 hours, and the stirring temperature is 25-40°C.

6. The method for preparing a bimetallic MOFs composite material according to claim 1, characterized in that: In steps (1) to (3): The cleaning is relatively independent and includes washing with a solvent, the solvent includes at least one of water, methanol, and ethanol, and the number of cleaning times is 3-5 times; The drying temperature is relatively independent of 60-100° C., and the drying time is relatively independent of 6-12 hours.

7. A bimetallic MOFs composite material prepared according to the method according to any one of claims 1-6.

8. Use of the bimetallic MOFs composite material according to claim 7 in the preparation of antibacterial materials and sewage treatment.

9. The use of the bimetallic MOFs composite material according to claim 8 in the preparation of antibacterial materials and sewage treatment, characterized in that: The antibacterial material inhibits at least one of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus.

10. The use of the bimetallic MOFs composite material according to claim 8 in the preparation of antibacterial materials and sewage treatment, characterized in that: The sewage is sewage containing PPCPs pollutants, more preferably sewage containing sulfamethoxazole.

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