A bimetallic MOFs composite material, a preparation method and application thereof

Abstract

This invention belongs to the field of functional nanomaterials and antibacterial technology, and discloses a bimetallic MOF composite material, its preparation method, and its application. The preparation of the composite material includes the following steps: dissolving a copper source and a cerium source in water, adding an alkaline precipitant to form a bimetallic hydroxide precipitate, and then heating the reaction to obtain CuO-CeO2 nanoparticles; dispersing the CuO-CeO2 nanoparticles in a ZIF-8 precursor solution, stirring the reaction to obtain CuO-CeO2@ZIF-8 composite particles; dispersing the composite particles in water, adding silver nitrate solution and a reducing agent, mixing evenly, adjusting the pH to 8.0-10.0, stirring the reaction to obtain the bimetallic MOF composite material. The bimetallic MOF composite material of this invention, by introducing silver nanoparticles and bimetallic nanozymes, forms a multiple synergistic antibacterial mechanism, achieving excellent antibacterial and PPCPs-type pollutant degradation performance.

Description

Technical Field

[0001] This invention belongs to the field of functional nanomaterials and antibacterial technology, and specifically relates to a bimetallic MOF composite material, its preparation method and application. Background Technology

[0002] With the widespread use and overuse of antibiotics, the emergence and spread of drug-resistant bacteria (such as superbugs) has become a major challenge in global public health. Traditional antimicrobial agents typically rely on a single bactericidal mechanism, such as blocking bacterial metabolic pathways or disrupting cell walls. However, this single mechanism gradually becomes ineffective against drug-resistant strains, leading to a significant decrease in antimicrobial efficacy. Furthermore, the performance of traditional antimicrobial agents is easily limited in complex environments (such as high temperatures and oxidizing media), making it difficult to meet diverse practical application needs. These problems have spurred an urgent need for novel multifunctional antimicrobial materials, especially those capable of integrating multiple synergistic antimicrobial mechanisms, to effectively combat 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 tunable structure. MOFs can not only serve as stable carriers for nanoparticles, but also endow composite materials with stronger functionalization capabilities by controlling pore structure and surface chemical properties. For example, Chinese patent application CN201911375608.1 discloses a method for preparing a zinc oxide-MOF composite antibacterial material, which uses an in-situ growth method to grow ZnO NPs on the surface and within the pores of MOFs-Ln, thus preparing a ZnO NPs@MOFs-Ln material with good antibacterial properties. Chinese patent application CN202211217688.X discloses a metal-organic framework nanocomposite, its preparation method, and its application, which loads tetramethylbenzidine (TMB) and horseradish peroxidase (HPR) onto the surface of a metal-organic framework (MOF) to form a metal-organic framework nanocomposite with antibacterial properties.

[0004] Nevertheless, current MOF-based antibacterial materials still face numerous 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-based antibacterial materials. Therefore, how to prepare MOF composite materials with stable loading of functional components and efficient synergistic antibacterial properties through efficient design and preparation methods has become a key technical challenge. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of the prior art, the primary objective of this invention is to provide a method for preparing bimetallic MOF composite materials.

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

[0007] Another objective of this invention is to provide the application of the above-mentioned bimetallic MOF composite material in the preparation of antibacterial materials and wastewater treatment.

[0008] The objective of this invention is achieved through the following solution:

[0009] A method for preparing a bimetallic MOF composite material includes the following steps:

[0010] (1) Dissolve copper source and cerium source in water, then add alkaline precipitant to form bimetallic hydroxide precipitate, and then heat to react, wash and dry to obtain CuO-CeO2 nanoparticles;

[0011] (2) The CuO-CeO2 nanoparticles were dispersed in a ZIF-8 precursor solution, stirred and reacted, and after the reaction was completed, they were washed and dried to obtain CuO-CeO2@ZIF-8 composite particles.

[0012] (3) Disperse the CuO-CeO2@ZIF-8 composite particles in water, then add silver nitrate solution and reducing agent, mix evenly and adjust pH to 8.0-10.0, stir to react, wash and dry after the reaction is completed to obtain bimetallic MOFs composite material.

[0013] In step (1):

[0014] In some embodiments, the copper source includes at least one of copper nitrate trihydrate (Cu(NO3)2·3H2O), copper chloride (CuCl2), copper sulfate (CuSO4), and copper acetate (Cu(CH3COO)2).

[0015] In some embodiments, the cerium source includes at least one of cerium nitrate hexahydrate (Ce(NO3)3·6H2O), cerium chloride (CeCl3), cerium sulfate (Ce2(SO4)3), and cerium acetate (Ce(CH3COO)3).

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

[0017] In some embodiments, the alkaline precipitant includes at least one of sodium hydroxide (NaOH) solution, potassium hydroxide (KOH) solution, ammonia (NH3·H2O), and sodium carbonate (Na2CO3) solution, with a concentration of 0.1-1M, and the amount added is 5%-20% of the total volume of the reaction solution.

[0018] In some embodiments, the addition of the alkaline precipitant can adjust the pH of the reaction solution to 8.0-10.5.

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

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

[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, an alkaline precipitant is added to form a precipitate of bimetallic hydroxide. After heating and reaction, CuO-CeO2 nanoparticles, i.e. bimetallic nanozymes, can be obtained.

[0023] In step (2):

[0024] In some embodiments, the ZIF-8 precursor solution comprises 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(NO3)2·6H2O), zinc chloride (ZnCl2), zinc acetate (Zn(CH3COO)2), and zinc sulfate (ZnSO4), wherein the concentration of zinc in the zinc salt in the ZIF-8 precursor solution is 0.1-1.0M.

[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 amount of the dispersant added is 1%-10% of the mass of the zinc salt;

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

[0029] In some embodiments, the mass ratio of the CuO-CeO2 nanoparticles to the total mass of 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, wherein the power of the ultrasonic-assisted dispersion is 200-300W and the time is 15-30 minutes;

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

[0032] In some embodiments, after the reaction is completed, a centrifugation operation is also included. After centrifugation, the obtained solid is washed and dried to obtain CuO-CeO2@ZIF-8 composite particles.

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

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

[0035] The purpose of step (2) in this invention is to synthesize ZIF-8 crystals while uniformly encapsulating CuO-CeO2 bimetallic nanoparticles with ZIF-8 crystals, ultimately forming CuO-CeO2@ZIF-8 composite particles.

[0036] In step (3):

[0037] In some embodiments, the mass ratio of the CuO-CeO2@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 150-300W, 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 (AgNO3) 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.

[0040] In some embodiments, the reducing agent includes at least one of dopamine (PDA), ascorbic acid (VC), and sodium hydroxide complex (such as NaBH4), and the amount of reducing agent added is such that the concentration of the reducing agent in the uniformly mixed solution is 0.01-0.1M.

[0041] In some embodiments, adjusting the pH means adding at least one of sodium hydroxide solution (0.01-0.1M), ammonia (0.5-2M), or sodium carbonate solution (0.01-0.1M) 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 including at least one of water and ethanol, and the number of cleaning cycles is 3-5.

[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 this invention is to reduce silver nanoparticles (AgNPs) in situ on the surface of CuO-CeO2@ZIF-8 composite particles, and finally obtain a bimetallic MOF composite material with high antibacterial properties.

[0046] In the preparation of multi-component composite materials, functional nanoparticles tend to aggregate, leading to insufficient exposure of active sites and thus reducing material performance. This invention achieves uniform distribution and effective loading of bimetallic nanozymes in composite materials by optimizing coordination precipitation and in-situ reduction processes.

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

[0048] Thirdly, this invention provides an application of bimetallic MOF composite materials in the preparation of antibacterial materials and in the treatment of wastewater.

[0049] The antibacterial material preferably inhibits at least one of the following bacterial species: Pseudomonas aeruginosa drug and methicillin-resistant Staphylococcus aureus.

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

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

[0052] (1) Highly Effective Antibacterial Properties: Traditional single-function antibacterial materials struggle to cope with complex pathogen infection scenarios. This invention organically integrates the peroxidase-mimicking activity and antibacterial ion release function of bimetallic nanozymes (CuO-CeO2@ZIF-8 composite particles) with the protective and catalytically enhancing properties of the matrix material, forming a multi-synergistic antibacterial mechanism and improving overall performance. The bimetallic MOF composite material of this invention achieves excellent antibacterial properties by introducing silver nanoparticles (AgNPs) and bimetallic nanozymes (CuO and CeO2). Silver nanoparticles have broad-spectrum antibacterial activity, capable of killing bacteria by disrupting bacterial cell walls and inhibiting cell metabolism; CuO and CeO2 bimetallic nanozymes catalyze the generation of reactive oxygen species (such as hydroxyl radicals) in a hydrogen peroxide environment, further enhancing the antibacterial effect. The synergistic effect of both enables the material to exhibit significant inhibitory effects against common Gram-positive bacteria, Gram-negative bacteria, and some drug-resistant bacteria.

[0053] (2) Highly efficient degradation of PPCPs pollutants: In the bimetallic MOFs composite material of the present invention, the active oxygen generated by CuO and CeO2 bimetallic nanozymes in the hydrogen peroxide environment can efficiently degrade sulfamethoxazole (SMX), a pollutant in personal care products (PPCPs), which is beneficial to the treatment of water pollution and ecological restoration. It is of great significance for further protecting ecological water sources and the ecological environment of pure water bodies.

[0054] (3) High efficiency and stability: Traditional antibacterial agents typically rely on a single bactericidal mechanism, making it difficult to effectively inhibit drug-resistant strains. Furthermore, their performance is easily degraded in complex environments (such as high temperatures and strong oxidizing media), further limiting their practical applications. This invention aims to develop a bimetallic nanozyme composite material with multiple antibacterial mechanisms. Through the synergistic catalytic effect of bimetallic nanozymes, combined with the stability and protective effect of the material structure, it can maintain high-efficiency antibacterial activity even in complex environments, breaking through the resistance barrier of drug-resistant bacteria and improving the applicability of the material in various practical scenarios. This composite material maintains good antibacterial performance and structural stability even in complex environments (such as high temperatures or high salt concentrations). The porous structure of ZIF-8 provides a stable carrier, offering not only excellent chemical stability but also effectively preventing the aggregation of silver nanoparticles and the inactivation of bimetallic nanozymes.

[0055] (4) Environmental friendliness: Many current nanomaterial preparation processes rely on complex, expensive, or environmentally unfriendly reagents and processes, hindering their large-scale application. The composite material of this invention employs a green chemical method, avoiding high-temperature, high-pressure conditions and the use of highly toxic reagents. Silver nanoparticles are prepared via in-situ reduction, reducing the risk of silver ion loss and environmental pollution. Furthermore, the composite material does not release harmful byproducts during use, making it suitable for applications with high environmental safety requirements, such as medical wastewater treatment and food packaging.

[0056] (5) Scalability and Application Potential: The composite material of this invention has a simple preparation process. By adjusting the ratio of bimetallic nanozymes, silver nanoparticles, and ZIF-8 crystals, different antibacterial requirements can be met. The material's high-efficiency antibacterial properties make it suitable for various scenarios, including antibacterial coatings for medical device surfaces, wastewater treatment, food packaging, and daily necessities. Its good performance and economy give it broad market prospects and application potential.

[0057] (6) High cost-effectiveness: By using bimetallic nanozymes to replace part of the precious metal antibacterial agents, this invention significantly reduces material costs. Simultaneously, the introduction of the ZIF-8 matrix improves the utilization efficiency of silver nanoparticles and reduces waste of antibacterial components. Furthermore, the bimetallic MOF composite material of this invention is reusable. Compared with traditional antibacterial materials, this invention achieves a good balance between cost and performance, making it a highly efficient and economical antibacterial solution. Attached Figure Description

[0058] Figure 1 The image shows the morphology of CuO-CeO2 nanoparticles in Example 1.

[0059] Figure 2 The image shows the morphology of the CuO-CeO2@ZIF-8 composite particles in Example 1.

[0060] Figure 3 The image shows the morphology of the CuO-CeO2@ZIF-8 / AgNPs composite material in Example 1.

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

[0062] Figure 5 The image shows a scanning electron microscope image of the CeO2 metal nanozyme particles prepared in step (1) of Comparative Example 5.

[0063] Figure 6 Here is a scanning electron microscope image of the AgNPs material prepared in Comparative Example 7;

[0064] Figure 7 The morphological changes of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus before and after one antibacterial treatment in Example 1 are shown in the figures: 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

[0065] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0066] Unless otherwise specified, the temperatures in the examples and comparative examples refer to those conducted at room temperature, which is 20-40°C.

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

[0068] Example 1

[0069] (1) Preparation of CuO-CeO2 nanoparticles

[0070] 0.01 mol of copper nitrate trihydrate (Cu(NO3)2·3H2O) and 0.03 mol of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) were dissolved in 100 mL of deionized water. The solution was stirred at 300 rpm for 30 minutes at 25 °C to form a homogeneous, clear solution. Then, 10 mL of 0.5 M sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 9.0, forming a precipitate of bimetallic hydroxide. This precipitate was heated at 180 °C for 12 hours, then separated by centrifugation at 8000 rpm for 8 minutes. The precipitate was washed four times with deionized water to remove residual ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain CuO-CeO2 nanoparticles.

[0071] (2) Synthesis of ZIF-8 and encapsulation with CuO-CeO2

[0072] 10g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 20g of 2-methylimidazole were added as ZIF-8 precursors to 50ml of methanol, followed by the addition of polyvinylpyrrolidone (PVP) at 5% of the zinc salt mass as a dispersant to prepare a ZIF-8 precursor solution. 0.5g of the prepared CuO-CeO2 nanoparticles were dispersed in the ZIF-8 precursor solution and ultrasonically assisted for 20 minutes at a power of 250W to ensure uniform particle distribution. The mixture was then stirred at 400rpm for 18 hours to allow the CuO-CeO2 nanoparticles to be uniformly coated with ZIF-8 crystals. After the reaction, the product was separated by centrifugation at 10000rpm for 8 minutes and washed four times with methanol to remove unreacted components. Finally, the product was dried at 80℃ for 8 hours to obtain CuO-CeO2@ZIF-8 composite particles.

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

[0074] 0.5 g of the obtained CuO-CeO2@ZIF-8 composite particles were dispersed in 50 mL of deionized water and dispersed using ultrasound at 22 °C for 20 minutes with a power of 200 W. Then, 4.62 mL of 0.05 M silver nitrate (AgNO3) solution was slowly added to achieve a silver ion to CuO-CeO2@ZIF-8 composite particle mass ratio of 1:20. Next, 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 carried out at 30 °C and stirred at 300 rpm for 6 hours to allow silver ions to be reduced in situ on the surface of the composite particles, forming silver nanoparticles (AgNPs). After the reaction was completed, the product was separated by centrifugation at 10,000 rpm for 8 minutes and washed four 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 bimetallic MOF composite material (i.e., CuO-CeO2@ZIF-8 / AgNPs composite material).

[0075] The scanning electron microscope image of CuO-CeO2 nanoparticles prepared in step (1) of Example 1 is shown below. Figure 1 As shown, the scanning electron microscope image of the CuO-CeO2@ZIF-8 composite particle material prepared in step (2) is as follows. Figure 2 As shown, the scanning electron microscope image of the CuO-CeO2@ZIF-8 / AgNPs composite material prepared in step (3) is as follows. Figure 3 As shown.

[0076] Example 2

[0077] (1) Preparation of CuO-CeO2 nanoparticles

[0078] CuO-CeO2 nanoparticles were prepared according to the method in Example 1, with the only difference being that the copper source was changed from copper nitrate trihydrate (Cu(NO3)2·3H2O) to copper chloride (CuCl2), while the amount remained the same, i.e., 0.01 mol.

[0079] (2) Synthesis of ZIF-8 and encapsulation with CuO-CeO2

[0080] The procedure was carried out exactly as described in Example 1.

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

[0082] The procedure was carried out exactly as described in Example 1.

[0083] The difference between Example 2 and Example 1 is that the copper source is changed from copper nitrate trihydrate to copper chloride.

[0084] Example 3

[0085] (1) Preparation of CuO-CeO2 nanoparticles

[0086] The procedure was carried out exactly as described in Example 1.

[0087] (2) Synthesis of ZIF-8 and encapsulation with CuO-CeO2

[0088] The procedure was carried out exactly as described in Example 1.

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

[0090] The method of Example 1 was followed, except that the reducing agent was replaced with a sodium hydroxide complex (NaBH4) instead of ascorbic acid (VC), and the amount added was kept at 0.162 g, i.e., 0.078 M.

[0091] The difference from Example 1 is that the reducing agent is changed from ascorbic acid to a sodium hydroxide complex (NaBH4).

[0092] Example 4

[0093] (1) Preparation of CuO-CeO2 nanoparticles

[0094] The method is the same as in Example 1, except that the molar ratio of copper in the copper source to cerium in the cerium source is changed from 1:3 to 1:2. Specifically, 0.01 mol of copper nitrate trihydrate and 0.02 mol of cerium nitrate hexahydrate are dissolved in 100 mL of deionized water, with the remaining steps unchanged.

[0095] (2) Synthesis of ZIF-8 and encapsulation with CuO-CeO2

[0096] The procedure was carried out exactly as described in Example 1.

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

[0098] The procedure was carried out exactly as described in Example 1.

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

[0100] Example 5

[0101] (1) Preparation of CuO-CeO2 nanoparticles

[0102] The procedure was carried out according to Example 1, except that the alkaline precipitant was replaced with 0.5M ammonia water (NH3·H2O) instead of 0.5M sodium hydroxide (NaOH) solution, while the amount added and other conditions remained the same.

[0103] (2) Synthesis of ZIF-8 and encapsulation with CuO-CeO2

[0104] The procedure was carried out exactly as described in Example 1.

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

[0106] The procedure was carried out exactly as described in Example 1.

[0107] The difference from Example 1 is that the alkaline precipitant is changed from sodium hydroxide solution to ammonia.

[0108] Example 6

[0109] (1) Preparation of CuO-CeO2 nanoparticles

[0110] The procedure was carried out exactly as described in Example 1.

[0111] (2) Synthesis of ZIF-8 and encapsulation with CuO-CeO2

[0112] The procedure was carried out exactly as described in Example 1.

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

[0114] The method of Example 1 was followed, except that the mass ratio of silver ions to CuO-CeO2@ZIF-8 composite particles was adjusted from 1:20 to 1:15, i.e., the amount of silver ions increased, requiring adjustments to the volume and concentration of the AgNO3 solution to achieve the new mass ratio. The amount of 0.05M silver nitrate (AgNO3) solution was increased from 4.62 mL to 6.18 mL. All other steps remained unchanged.

[0115] The difference between Example 6 and Example 1 is that the mass ratio of silver ions to CuO-CeO2@ZIF-8 composite particles is adjusted from 1:20 to 1:15.

[0116] Example 7

[0117] (1) Preparation of CuO-CeO2 nanoparticles

[0118] The procedure was carried out exactly as described in Example 1.

[0119] (2) Synthesis of ZIF-8 and encapsulation with CuO-CeO2

[0120] The method of Example 1 is followed, except that the dispersant is replaced by polyethylene glycol (PEG) (molecular weight 4000 Da) instead of polyvinylpyrrolidone (PVP), and the amount of dispersant added is kept at 5% of the mass of zinc salt.

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

[0122] The procedure was carried out exactly as described in Example 1.

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

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

[0125]

[0126] Comparative Example 1: CuO-CeO2 nanoparticles

[0127] CuO-CeO2 nanoparticles were synthesized using copper and cerium sources without the addition of ZIF-8 and AgNPs.

[0128] 0.01 mol of copper nitrate trihydrate (Cu(NO3)2·3H2O) and 0.03 mol of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) were dissolved in 100 mL of deionized water. The solution was stirred at 300 rpm for 30 minutes at 25 °C to form a homogeneous, clear solution. Then, 10 mL of 0.5 M sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 9.0, forming a precipitate of bimetallic hydroxide. This precipitate was heated at 180 °C for 12 hours, then separated by centrifugation at 8000 rpm for 8 minutes. The precipitate was washed four times with deionized water to remove residual ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain CuO-CeO2 nanoparticles.

[0129] Comparative Example 2: CuO-CeO2 / AgNPs composite material

[0130] 0.01 mol of copper nitrate trihydrate (Cu(NO3)2·3H2O) and 0.03 mol of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) were dissolved in 100 mL of deionized water. The solution was stirred at 300 rpm for 30 minutes at 25 °C to form a homogeneous, 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. The precipitate was heated at 180 °C for 12 hours, then separated by centrifugation at 8000 rpm for 8 minutes. The precipitate was washed four times with deionized water to remove residual ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain CuO-CeO2 nanoparticles.

[0131] 0.5 g of the obtained CuO-CeO2 nanoparticles were dispersed in 50 mL of deionized water and dispersed using ultrasound at 22 °C for 20 min with a power of 200 W. Then, 4.62 mL of 0.05 M silver nitrate (AgNO3) solution was slowly added to achieve a silver ion to CuO-CeO2 nanoparticle mass ratio of 1:20. Next, 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 carried out at 30 °C and stirred at 300 rpm for 6 hours to allow silver ions to be reduced in situ on the surface of CuO-CeO2 nanoparticles to form silver nanoparticles (AgNPs). After the reaction, the product was separated by centrifugation at 10000 rpm for 8 min and washed four 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 CuO-CeO2 / AgNPs composite material.

[0132] Comparative Example 3: CuO-CeO2@ZIF-8 composite material

[0133] (1) Preparation of CuO-CeO2 nanoparticles

[0134] 0.01 mol of copper nitrate trihydrate (Cu(NO3)2·3H2O) and 0.03 mol of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) were dissolved in 100 mL of deionized water. The solution was stirred at 300 rpm for 30 minutes at 25 °C to form a homogeneous, 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. The precipitate was heated at 180 °C for 12 hours, then separated by centrifugation at 8000 rpm for 8 minutes. The precipitate was washed four times with deionized water to remove residual ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain CuO-CeO2 nanoparticles.

[0135] (2) Synthesis of ZIF-8 and encapsulation with CuO-CeO2

[0136] 10g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 20g of 2-methylimidazole were added to 50ml of methanol, followed by the addition of polyvinylpyrrolidone (PVP) at 5% of the zinc salt mass as a dispersant to prepare a ZIF-8 precursor solution. 0.5g of the prepared CuO-CeO2 nanoparticles were dispersed in the ZIF-8 precursor solution and ultrasonically assisted for 20 minutes at a power of 250W to ensure uniform particle distribution. The reaction was then stirred at 400rpm for 18 hours to allow the CuO-CeO2 nanoparticles to be uniformly coated with ZIF-8 crystals. After the reaction, the product was separated by centrifugation at 10000rpm for 8 minutes and washed four times with methanol to remove unreacted components. Finally, the product was dried at 80℃ for 8 hours to obtain the CuO-CeO2@ZIF-8 composite material.

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

[0138] (1) Preparation of CuO nanoparticles

[0139] 0.01 mol of copper nitrate trihydrate (Cu(NO3)2·3H2O) was dissolved in 100 mL of deionized water. The solution was stirred at 300 rpm for 30 minutes at 25 °C to form a homogeneous, clear solution. Then, 10 mL of 0.5 M sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 9.0, forming a precipitate of metal hydroxide. The precipitate was heated at 180 °C for 12 hours, then separated by centrifugation at 8000 rpm for 8 minutes. The precipitate was washed four 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 CuO encapsulation

[0141] 10g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 20g of 2-methylimidazole were added to 50ml of methanol as ZIF-8 precursors. Then, polyvinylpyrrolidone (PVP) at 5% of the zinc salt mass was added as a dispersant to prepare a ZIF-8 precursor solution. 0.5g of CuO nanoparticles prepared above were dispersed in the ZIF-8 precursor solution and ultrasonically assisted for 20 minutes using 250W power to ensure uniform particle distribution. The reaction was then stirred at 400rpm for 18 hours to ensure uniform coating of CuO nanoparticles with ZIF-8 crystals. After the reaction, the product was separated by centrifugation at 10000rpm for 8 minutes and washed four times with methanol to remove unreacted components. Finally, the product was dried at 80℃ 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 dispersed using ultrasound at 22 °C for 20 minutes with a power of 200 W. Then, 4.62 mL of 0.05 M silver nitrate (AgNO3) solution was slowly added to achieve a silver ion to CuO@ZIF-8 composite particle mass ratio of 1:20. Next, 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 carried out at 30 °C and stirred at 300 rpm for 6 hours to allow silver ions to be reduced in situ on the surface of the CuO@ZIF-8 composite particles, forming silver nanoparticles (AgNPs). After the reaction, the product was separated by centrifugation at 10000 rpm for 8 minutes and washed four 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 CuO@ZIF-8 / AgNPs composite material.

[0144] The scanning electron microscope image of CuO nanoparticles prepared in step (1) of Comparative Example 4 is shown below. Figure 4 As shown.

[0145] Comparative Example 5: CeO2@ZIF-8 / AgNPs composite material

[0146] (1) Preparation of CeO2 nanoparticles

[0147] 0.01 mol of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) was dissolved in 100 mL of deionized water. The solution was stirred at 300 rpm for 30 minutes at 25 °C to form a homogeneous, clear solution. Then, 10 mL of 0.5 M sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 9.0, forming a precipitate of metal hydroxide. The precipitate was heated at 180 °C for 12 hours, then separated by centrifugation at 8000 rpm for 8 minutes. The precipitate was washed four times with deionized water to remove residual ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain CeO2 nanoparticles.

[0148] (2) Synthesis of ZIF-8 and encapsulation with CeO2

[0149] 10g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 20g of 2-methylimidazole were added to 50ml of methanol as ZIF-8 precursors. Then, polyvinylpyrrolidone (PVP) at 5% of the zinc salt mass was added as a dispersant to prepare a ZIF-8 precursor solution. 0.5g of CeO2 nanoparticles prepared above were dispersed in the ZIF-8 precursor solution and ultrasonically assisted for 20 minutes using 250W power to ensure uniform particle distribution. The reaction was then stirred at 400rpm for 18 hours to ensure uniform coating of CeO2 particles with ZIF-8 crystals. After the reaction, the product was separated by centrifugation at 10000rpm for 8 minutes and washed four times with methanol to remove unreacted components. Finally, the product was dried at 80℃ for 8 hours to obtain CeO2@ZIF-8 composite particles.

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

[0151] 0.5 g of the obtained CeO2@ZIF-8 composite particles were dispersed in 50 mL of deionized water and dispersed using ultrasound at 22 °C for 20 minutes with a power of 200 W. Then, 4.62 mL of 0.05 M silver nitrate (AgNO3) solution was slowly added to achieve a silver ion to CeO2@ZIF-8 composite particle mass ratio of 1:20. Next, 0.75 g of ascorbic acid (VC) was added as a reducing agent, and 0.05 M sodium hydroxide (NaOH) solution was added to adjust the pH of the solution to 9.0. The reaction was carried out at 30 °C and stirred at 300 rpm for 6 hours to allow silver ions to be reduced in situ on the surface of the CeO2@ZIF-8 composite particles, forming silver nanoparticles (AgNPs). After the reaction, the product was separated by centrifugation at 10000 rpm for 8 minutes and washed four 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 CeO2@ZIF-8 / AgNPs composite material.

[0152] The scanning electron microscope image of CeO2 nanoparticles prepared in step (1) of Comparative Example 5 is shown below. Figure 5 As shown.

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

[0154] (1) Synthesis of ZIF-8

[0155] 10 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 20 g of 2-methylimidazole were added to 50 ml of methanol, followed by the addition of polyvinylpyrrolidone (PVP) at 5% of the zinc salt mass as a dispersant to prepare a ZIF-8 precursor solution. The solution was dispersed using ultrasound at 250 W for 20 minutes to ensure uniform particle distribution. The reaction was then 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 four 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 using ultrasound at 22 °C for 20 minutes with a power of 200 W. Then, 4.62 mL of 0.05 M silver nitrate (AgNO3) solution was slowly added to achieve a silver ion to ZIF-8 particle mass ratio of 1:20. Next, 0.75 g of ascorbic acid (VC) was added as a reducing agent, and 0.05 M sodium hydroxide (NaOH) solution was added to adjust the pH of the solution to 9.0. The reaction was carried out at 30 °C and 300 rpm for 6 hours, allowing silver ions to be reduced in situ on the surface of the 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 four 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] 4.62 mL of a 0.05 M silver nitrate (AgNO3) solution was taken, and 0.75 g of ascorbic acid (VC) was added as a reducing agent. Then, 0.05 M sodium hydroxide (NaOH) solution was added to adjust the pH of the solution to 9.0. The reaction was carried out at 30 °C and stirred at 300 rpm for 6 hours to reduce silver ions into silver nanoparticles (AgNPs). After the reaction was completed, the product was separated by centrifugation at 10,000 rpm for 8 minutes and washed four 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 AgNPs material.

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

[0161] Comparative Example 8: ZIF-8 material

[0162] 10 g of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 20 g of 2-methylimidazole were added to 50 ml of methanol, followed by the addition of polyvinylpyrrolidone (PVP) at 5% of the zinc salt mass as a dispersant to prepare a ZIF-8 precursor solution. The solution was dispersed using ultrasound at 250 W for 20 minutes to ensure uniform particle distribution. The reaction was then 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 four 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] 0.01 mol of copper nitrate trihydrate (Cu(NO3)2·3H2O) and 0.03 mol of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) were dissolved in 100 mL of deionized water. The solution was stirred at 300 rpm for 30 minutes at 25 °C to form a homogeneous, clear solution. Then, 10 mL of 0.5 M sodium hydroxide (NaOH) solution was slowly added dropwise to adjust the pH to 9.0, forming a precipitate of bimetallic hydroxide. The precipitate was heated at 180 °C for 12 hours, then separated by centrifugation at 8000 rpm for 8 minutes. The precipitate was washed four times with deionized water to remove residual ions and impurities. Finally, the product was dried at 80 °C for 8 hours to obtain NiO-CuO nanoparticles.

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

[0167] The procedure was carried out exactly as described in Example 1, except that the CuO-CeO2 nanoparticles in Example 1 were replaced with NiO-CuO nanoparticles.

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

[0169] The procedure was carried out exactly as described in Example 1.

[0170] In Comparative Example 9, CuO-CeO2 nanoparticles were replaced with NiO-CuO nanoparticles.

[0171] Comparative Example 10: CuO-CeO2@MOF-5 / AgNPs composite material

[0172] (1) Preparation of CuO-CeO2 nanoparticles

[0173] The procedure was carried out exactly as described in Example 1.

[0174] (2) Synthesis of MOF-5 and encapsulation with CuO-CeO2

[0175] The procedure was carried out exactly as described in Example 1, except that 20g of 2-methylimidazole in the precursor solution of Example 1 was replaced with 20g of phthalic acid (BDC), while the other steps remained unchanged.

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

[0177] The procedure was carried out exactly as described in Example 1.

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

[0179] Comparative Example 11: CuO-CeO2@ZIF-8 / FeNPs composite material

[0180] (1) Preparation of CuO-CeO2 nanoparticles

[0181] The procedure was carried out exactly as described in Example 1.

[0182] (2) Synthesis of ZIF-8 and encapsulation with CuO-CeO2

[0183] The procedure was carried out exactly as described in Example 1.

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

[0185] The procedure was exactly the same as in Example 1, except that the 4.62 mL of 0.05 M silver nitrate (AgNO3) solution in Example 1 was replaced with 4.62 mL of 0.05 M ferric nitrate (Fe(NO3)3) solution. All other steps were the same as in Example 1.

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

[0187] Test Example 1 Antibacterial Effect

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

[0189] Tested bacterial species: Pseudomonas aeruginosa (ATCC 15442), methicillin-resistant Staphylococcus aureus (ATCC43300).

[0190] Test conditions: The initial concentration of both *Pseudomonas aeruginosa* and methicillin-resistant *Staphylococcus aureus* was 3 × 10⁻⁶. 7The bacterial concentration was CFU / mL, the bacterial culture volume was 50 ml, and the sample material dosage was 0.4 g / L. The bacterial concentration before and after the experiment was obtained by plate counting, and the test results were obtained by comparison.

[0191] Table 2. Test results of different materials in removing Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus.

[0192]

[0193] Based on the above experimental data and Figure 7 As shown, the comparison between the examples and comparative examples clearly demonstrates that the CuO-CeO2@ZIF-8 / AgNPs composite material of our invention exhibits significant advantages in the antibacterial field. Experimental results show that the composite material in Example 1 achieved an antibacterial rate of up to 99% against *Pseudomonas aeruginosa* and 97% against methicillin-resistant *Staphylococcus aureus*. In contrast, Comparative Example 1 (CuO-CeO2 nanoparticles) showed antibacterial rates of only 55.2% and 50.3%, significantly lower than that of Example 1. Furthermore, the antibacterial rates of Comparative Example 2 (CuO-CeO2 / AgNPs composite material) were 74.9% and 71.6%, also far lower than that of Example 1, further proving that the synergistic effect of the components in the composite material is crucial for its antibacterial effect. Experimental results also show that before and after the antibacterial experiment, *Pseudomonas aeruginosa* and methicillin-resistant *Staphylococcus aureus* underwent significant mineralization and fragmentation (e.g., Figure 7 As shown in the figure, this further verifies the superior antibacterial properties of the material.

[0194] Example 1 (using the synergistic effect of ZIF-8 support material and silver nanoparticles) demonstrated optimal antibacterial effect and material stability. Changing the copper source (Example 2) and reducing agent (Example 3) affected the solubility and reactivity of metal ions, as well as the formation rate and uniformity of silver nanoparticles, leading to a decrease in antibacterial effect. Adjusting the molar ratio of copper to cerium (Example 4) and changing the alkaline precipitant (Example 5) somewhat affected the antibacterial effect, but still maintained a high level (greater than 90%). Changing the dispersant (Example 7) affected the dispersibility and stability of the material, resulting in a decrease in antibacterial effect. Although Example 6 increased the silver nanoparticle content, the antibacterial effect was still lower than that of Example 1. This is because excessive silver nanoparticles may lead to excessive silver aggregation, uneven or excessive release of silver ions, and changes in the material structure, thereby reducing the antibacterial effect. An appropriate amount of silver nanoparticles can achieve the best antibacterial effect, while too much may have side effects. Overall, the synergistic effect of ZIF-8 and silver nanoparticles, and a suitable reducing agent and copper-cerium ratio are key factors in improving the antibacterial effect.

[0195] The above results fully demonstrate the superior efficacy of the composite material against two typical pathogens. In contrast, Comparative Example 1 (CuO-CeO2 nanoparticles only) and other comparative groups showed significantly lower antibacterial effects, indicating that a single catalyst lacks sufficient antibacterial activity. Although Comparative Examples 2, 3, 4, and 5 added silver nanoparticles or ZIF-8 to the composite material, their antibacterial effects were still lower than those of Example 1 due to the lack of a reasonable synergistic effect. In particular, in Comparative Example 2, the antibacterial effect of the system combining CuO-CeO2 nanoparticles and AgNPs was only 74.9% and 71.6%, respectively. This was mainly due to the lack of ZIF-8 support, resulting in poor material stability and dispersibility, thus reducing its antibacterial performance. In Comparative Examples 4 and 5, after removing CeO2 or CuO, the antibacterial effect against Pseudomonas aeruginosa decreased to 60.7% and 61.2%, and the antibacterial effect against methicillin-resistant Staphylococcus aureus decreased to 56.5% and 57.9%, further demonstrating the synergistic effect of bimetallic nanozymes in the antibacterial process.

[0196] In Comparative Example 8, the antibacterial rate using ZIF-8 alone was extremely low (4.2% and 3.7%), indicating that ZIF-8 itself has a weak antibacterial effect on the tested bacteria, mainly acting as a carrier and structural support. In Comparative Example 9 (NiO-CuO@ZIF-8 / AgNPs) and Comparative Example 11 (CuO-CeO2@ZIF-8 / FeNPs), the antibacterial rate was lower than that of the main example sample, indicating that the addition of other metal oxides (such as NiO) and other metal nanoparticles (such as FeNPs) failed to effectively improve the antibacterial performance, and may even have slightly inhibited it due to the interaction between metals. The antibacterial rate of Comparative Example 10 (CuO-CeO2@MOF-5 / AgNPs) was 72.1% and 69.8%, respectively. Compared with the Example 1 sample using ZIF-8, the antibacterial effect was reduced, further demonstrating that ZIF-8 has a better antibacterial synergistic effect in this composite material.

[0197] In summary, our invention significantly enhances the antibacterial effect through multiple synergistic mechanisms (including bimetallic catalysis, silver ion release, ZIF-8 support, and a highly efficient reduction process), maintaining an antibacterial rate above 90% even under various experimental conditions. This remarkable advantage demonstrates the immense application potential of the CuO-CeO2@ZIF-8 / AgNPs composite material in the field of antibacterial applications, effectively combating common pathogens such as Escherichia coli and Staphylococcus aureus. This material not only exhibits good stability but also, through rational component design, possesses strong prospects for industrial applications, suitable for multiple fields such as medical devices, wastewater treatment, and food packaging.

[0198] Test Example 2 Security Test

[0199] Test subject: Material of Example 1 (CuO-CeO2@ZIF-8 / AgNPs).

[0200] Test item: CCK-8 assay for the cytotoxicity of composite materials

[0201] Test conditions:

[0202] L929 fibroblasts were used as a model in 96-well plates at a concentration of 10... 5 Cells were seeded at a density of 1 cell / well and incubated at 37°C and 5% CO2 for 24 hours. The culture medium was discarded, and culture medium was added to the blank control group. Different concentrations of test samples were added to the test groups. After 24 hours of incubation, the cells were removed, and three replicates were set up for each concentration. After 24 hours of treatment, 10 μL of CCK-8 reagent was added to each well, and incubation continued for 2 hours. The OD value was measured at 450 nm using a microplate reader, and the cell viability was calculated using this value.

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

[0204]

[0205]

[0206] According to experimental data, the CuO-CeO2@ZIF-8 / AgNPs material exhibited good biocompatibility with L929 cells at different concentrations. At a concentration of 10 μg / mL, the cell viability was 97%, close to 100%, with almost no significant toxic effects on the cells, indicating that the material has very good biocompatibility at low concentrations and is suitable for low-dose biomedical applications. As the concentration increased to 50 μg / mL, the cell viability decreased slightly to 93%, but remained at a high level, indicating that the material has very little impact on cells at moderate concentrations and has good safety. At a concentration of 100 μg / mL, the cell viability decreased to 84%, which, although a decrease, still met the safety standards for biomaterials. Overall, the CuO-CeO2@ZIF-8 / AgNPs material exhibited low toxicity to L929 cells in the concentration range of 10-100 μg / mL, indicating good biocompatibility at these concentrations and suitability for various biomedical applications, especially as a carrier material or antibacterial material.

[0207] Test Example 3: Degradation Test of PPCPs

[0208] my country is a major agricultural country with a large livestock and poultry farming industry. To treat and prevent livestock and poultry diseases or promote their growth, antibiotics and bactericides are often added to feed, resulting in a large amount of personal care product (PPCP) pollutants in livestock wastewater. Existing studies have shown that the ecotoxicity of residual PPCPs in the environment is diverse, and they exhibit significant bioaccumulation in organisms and humans, thus posing a potential threat to the ecological environment and human health. This test uses sulfamethoxazole (SMX), a representative PPCP, as the target pollutant to explore the effectiveness of bimetallic MOF composite materials in degrading PPCPs.

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

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

[0211]

[0212]

[0213] Example 1 demonstrated a 92.30% degradation rate of sulfamethoxazole (SMX), showcasing the high efficiency of the CuO-CeO2@ZIF-8 / AgNPs composite material in catalytic degradation. This result indicates that the synergistic effect of CuO, CeO2, ZIF-8, and AgNPs in the composite material plays a crucial role in the degradation reaction. In contrast, while the degradation rates of other examples decreased slightly, they generally remained at a high level (88.50%-91.50%), suggesting that optimizing different factors (such as copper source, reducing agent, and silver ion concentration) can improve the degradation effect.

[0214] Comparing Examples 2 and 3, we observed that the changes in the copper source (replacing copper nitrate with copper chloride) and the choice of reducing agent (ascorbic acid and sodium hydroxide complex) had a certain impact on the degradation rate. Although these changes slightly reduced the catalytic performance, the degradation rate was still higher than that of general catalysts, indicating that the basic catalytic performance of the material remained good.

[0215] In Examples 4 and 5, variations in the component ratio and the precipitant affected the catalytic effect. Adjusting the Cu:Ce molar ratio and using different precipitants altered the structure of the composite material and the distribution of catalytic sites, leading to changes in the catalytic effect and a slight decrease in degradation efficiency. However, overall, the degradation rates in all examples remained high, demonstrating strong catalytic stability and potential.

[0216] In Example 6, increasing the silver content resulted in a degradation rate of 91.50%, close to the baseline level, indicating that silver nanoparticles promote the catalytic reaction, especially in photocatalysis and silver ion release. However, excessive AgNPs may have covered the catalytic sites, leading to a decrease in catalytic performance and failing to further improve the degradation effect.

[0217] Example 7 used PEG as a dispersant to improve the dispersibility of the material, achieving a degradation rate of 89.80%. Although this was an improvement, it did not reach the expected performance enhancement. This indicates that the dispersant has limited effect on improving the catalytic effect, and its main role is in the stability and dispersibility of the material.

[0218] The comparative groups (Comparative Examples 1-11) showed that all samples not using the CuO-CeO2@ZIF-8 / AgNPs composite material generally had low degradation rates, especially Comparative Example 8, which had a degradation rate of only 7.40%. This result verifies the high efficiency and unique role of the CuO-CeO2@ZIF-8 / AgNPs composite material in the degradation of sulfamethoxazole. Comparative Examples 4 and 5 (65.10% and 67.30%, respectively) demonstrated the low efficiency of single catalytic components (such as CuO or CeO2) lacking synergistic effects, further emphasizing the synergistic effect of different components in the composite material on improving the catalytic effect.

[0219] For other comparative examples (such as Comparative Example 2, Comparative Example 3, and Comparative Example 4), although the degradation rates were lower, they still demonstrated 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 effect of AgNPs in improving catalytic performance, while Comparative Example 4 (65.10%) reflected the lack of CeO2, indicating that the synergistic effect of metal nanoparticles (i.e., metal nanozymes) and ZIF-8 was not fully manifested.

[0220] Furthermore, the degradation rates of Comparative Examples 9 and 10 (62.50% and 78.00%, respectively) were relatively high, possibly due to certain specific conditions playing a stronger role in these materials, but still could not match the effect of the composite material in the examples. Overall, the CuO-CeO2@ZIF-8 / AgNPs composite material exhibited significant catalytic performance in the degradation of sulfamethoxazole, and the individual components in the composite material (CuO, CeO2, ZIF-8, and AgNPs) significantly enhanced the catalytic effect through synergistic action. In contrast, the catalytic effect of using CuO, CeO2, ZIF-8, or AgNPs alone was significantly lower than that of the composite material, demonstrating the overall efficiency of the composite material. Although adjusting different material compositions (such as copper source, reducing agent, silver content, etc.) can optimize catalytic performance, increments exceeding certain parameters may lead to efficiency saturation, failing to significantly improve the catalytic effect. Ultimately, the optimal catalytic effect in the examples, especially in terms of silver content and catalyst ratio, demonstrates the high potential and innovation of this material in catalytic degradation.

[0221] Test Example 4: Recyclability Test

[0222] Test subject: Material of Example 1 (CuO-CeO2@ZIF-8 / AgNPs).

[0223] Test items: antibacterial effect and antibiotic degradation cycle performance test.

[0224] Test conditions:

[0225] The antibacterial effect test conditions were the same as in Test 1, and the antibiotic degradation effect test conditions were the same as in Test 3. After each test, the sample was centrifuged and washed with distilled water. The precipitated particles were then collected and tested again, and the cycle was repeated ten times.

[0226] Table 5 Example 1 Antibacterial and Degradative Antibiotic Cyclic Performance Test

[0227]

[0228] The CuO-CeO2@ZIF-8 / AgNPs material maintained a high level of antibacterial efficacy after ten cycles of use. Although the bactericidal rate and antibiotic degradation rate decreased—the bactericidal rate against Pseudomonas aeruginosa decreased from 99.3% to 87.7%, against methicillin-resistant Staphylococcus aureus from 97.8% to 83.5%, and against sulfamethoxazole from 92.30% to 86.3%—it still exhibited strong reusability. The decrease in efficacy may be due to a reduction in silver ion release and loss of surface-active components. However, the material still maintains a high antibacterial rate and antibiotic degradation efficiency, demonstrating its long-lasting effectiveness and stability in practical applications, making it suitable for continued use in environments requiring multiple applications.

[0229] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. The application of bimetallic MOF composite materials in wastewater treatment, characterized by: The bimetallic MOFs composite material is prepared by the following steps: (1) Dissolve copper and cerium sources in water, then add an alkaline precipitant to form a bimetallic hydroxide precipitate, and then heat to react, wash and dry to obtain CuO-CeO2 nanoparticles; (2) The CuO-CeO2 nanoparticles were dispersed in a ZIF-8 precursor solution, stirred and reacted, and after the reaction was completed, they were washed and dried to obtain CuO-CeO2@ZIF-8 composite particles; (3) Disperse the CuO-CeO2@ZIF-8 composite particles in water, then add silver nitrate solution and reducing agent, mix evenly and adjust pH to 8.0-10.0, stir to react, wash and dry after reaction to obtain bimetallic MOFs composite material; The wastewater in question contains PPCPs (Polypropylene Carbonate Powders).

2. The application of the bimetallic MOFs composite material according to claim 1 in wastewater treatment, 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 copper in the copper source to cerium in the cerium source is 1:1 to 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 0.1-1 M; The pH of the reaction solution is adjusted to 8.0-10.5 after the alkaline precipitant is added; In the heating reaction, the heating time is 10-15 hours, and the stirring temperature is 160-200℃.

3. The application of the bimetallic MOFs composite material according to claim 1 in wastewater treatment, characterized in that: In step (2): The ZIF-8 precursor solution comprises 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 zinc in the zinc salt in the ZIF-8 precursor solution is 0.1-1.0 M. The organic framework comprises 2-methylimidazole, and the concentration of the organic framework in the ZIF-8 precursor solution is 50-500 mg / L; The dispersant includes at least one of polyvinylpyrrolidone, sodium dodecyl sulfate, and polyethylene glycol, and the amount of the dispersant added is 1%-10% of the mass of the zinc salt; The solvent includes at least one of ethanol, methanol, dimethyl thionamide, and N,N-dimethylformamide.

4. The application of the bimetallic MOFs composite material according to claim 1 in wastewater treatment, characterized in that: In step (2): The mass ratio of the CuO-CeO2 nanoparticles to the total mass of zinc salt, organic framework, and dispersant in the ZIF-8 precursor solution is 1:10-1:

80. The dispersion includes ultrasonic-assisted dispersion, wherein the power of the ultrasonic-assisted dispersion is 200-300W and the time is 15-30 minutes; The stirring rate during the reaction is 300-500 rpm, the temperature is 20-45℃, and the time is 12-24 hours.

5. The application of the bimetallic MOFs composite material according to claim 1 in wastewater treatment, characterized in that: In step (3): The mass ratio of CuO-CeO2@ZIF-8 composite particles to water is 1:50-1:200; The concentration range of the silver nitrate solution is 0.01-0.1 M, and the mass ratio of silver ions to the CuO-CeO2@ZIF-8 composite particles is 1:10-1:

50. The reducing agent includes at least one of dopamine, ascorbic acid, and sodium hydroxide complex, and the amount of reducing agent added satisfies the requirement that the concentration of the reducing agent in the uniformly mixed solution is 0.01-0.1 M; The pH adjustment refers to adjusting the pH by adding at least one of sodium hydroxide solution, ammonia water, and sodium carbonate solution. The stirring reaction rate is 200-500 rpm, the reaction time is 4-8 hours, and the stirring temperature is 25-40℃.

6. The application of the bimetallic MOFs composite material according to claim 1 in wastewater treatment, characterized in that: In steps (1)-(3): Each cleaning process is relatively independent and includes washing with a solvent, wherein the solvent includes at least one of water, methanol, and ethanol, and the number of cleaning cycles is 3-5. The drying temperature is 60-100℃ and the drying time is 6-12 hours.

7. The application of the bimetallic MOFs composite material according to claim 1 in wastewater treatment, characterized in that: The wastewater in question is wastewater containing sulfamethoxazole.

Images