Method for preparing nano ZnO / silver-loaded zirconium phosphate composite antibacterial agent through self-assembly

Abstract

The invention relates to the technical field of antibacterial materials, and discloses a method for preparing a nano ZnO / silver-loaded zirconium phosphate composite antibacterial agent through self-assembly, and the method comprises the following steps: S1, reacting zinc salt with alkali in ethylene glycol to generate nano ZnO, so as to obtain a ZnO-ethylene glycol dispersion liquid; s2, dispersing silver-loaded zirconium phosphate into ethylene glycol to obtain silver-loaded zirconium phosphate dispersion liquid; and S3, dropwise adding the ZnO-ethylene glycol dispersion liquid into the silver-loaded zirconium phosphate dispersion liquid, carrying out self-assembly under the condition that the pH value is 6-7, and separating out a product, thereby obtaining the nano ZnO / silver-loaded zirconium phosphate composite antibacterial agent with better antibacterial property.

Description

Technical Field

[0001] This invention relates to the field of antibacterial materials technology, and in particular to a method for self-assembling a nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent. Background Technology

[0002] Based on their chemical composition, antibacterial agents are mainly divided into three categories: natural, organic, and inorganic. Natural antibacterial agents, including chitosan and propolis, are safe and environmentally friendly, but their heat resistance and other stability are relatively poor. Organic antibacterial agents, such as quaternary ammonium salts and triclosan, are easy to prepare, but are easily lost due to their solubility and have poor heat resistance. Their practical application is limited during polymer melt processing due to poor temperature resistance and long-term effectiveness. Among inorganic antibacterial agents, whether metal ion releasing type (such as Ag...)... + Zn 2+ Whether it is photocatalytic (such as ZnO2, TiO2) or composite (such as Ag / ZnO), they all have advantages such as high stability and broad antibacterial spectrum, and are generally not prone to inducing bacterial resistance, and have good safety. Therefore, they show obvious advantages in fields where long-lasting antibacterial effects are required.

[0003] In inorganic antibacterial agents, nano-zinc oxide antibacterial agents generate reactive oxygen species (ROS, such as ·OH, O2·) through photocatalysis. - Zinc oxide nanoparticles exhibit multiple antibacterial mechanisms, including zinc ion release and defective state antibacterial activity, enabling them to broadly kill both Gram-positive and Gram-negative bacteria. However, the photocatalytic antibacterial mechanism of zinc oxide nanoparticles has a narrow light response range (requiring ultraviolet irradiation), limiting its practical applications. Furthermore, the high surface energy of nanoparticles makes them prone to agglomeration, forming micron-sized aggregates and reducing the active surface area. Therefore, further improving the antibacterial properties of zinc oxide nanoparticles under dark conditions, while maintaining their specific size, is of significant practical importance.

[0004] Patent CN119791133A discloses a method for preparing a nano-zinc oxide composite silver ion antibacterial agent. The method involves dispersing nano-zinc oxide powder synthesized using the sol-gel method in deionized water, adding an activator and surfactant, stirring for 3-5 minutes, then adding silver-loaded sodium zirconium phosphate powder, stirring for another 30-60 minutes, filtering, drying the resulting precipitate, and then removing the surfactant and activator through calcination to obtain a composite antibacterial agent composed of nano-zinc oxide and silver-loaded sodium zirconium phosphate. This patent reduces the aggregation of nano-zinc oxide by composited on the surface of cubic crystals of silver-loaded sodium zirconium phosphate, and utilizes the difference in antibacterial mechanisms between zinc oxide and silver ions to produce a synergistic antibacterial effect, thus improving the antibacterial efficacy. However, this patented method suffers from problems such as abnormal growth of nano-zinc oxide during calcination and insufficient improvement in antibacterial activity. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for self-assembling a nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent. Using this method, the prepared nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent can exhibit better antibacterial properties.

[0006] The specific technical solution of this invention is as follows: A method for self-assembling a nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent, comprising the following steps: S1: Nano-ZnO is generated in ethylene glycol by reacting zinc salt with alkali to obtain ZnO-ethylene glycol dispersion; S2: Disperse silver-loaded zirconium phosphate in ethylene glycol to obtain a silver-loaded zirconium phosphate dispersion; S3: Add ZnO-ethylene glycol dispersion to silver-loaded zirconium phosphate dispersion, and allow self-assembly to occur at pH 6-7. Separate the product to obtain nano ZnO / silver-loaded zirconium phosphate composite antibacterial agent.

[0007] This invention utilizes the principles of colloidal hydrogen bonding and electrostatic self-assembly to achieve conformal coating of nano-zinc oxide and silver-loaded zirconium phosphate. Specifically, by synthesizing nano-zinc oxide in ethylene glycol, hydrogen bonds can be formed between the hydroxyl groups in ethylene glycol and the surface of nano-zinc oxide. During the assembly process, another hydroxyl group in the ethylene glycol molecule further forms hydrogen bonds with the silver-loaded zirconium phosphate. The nano-zinc oxide and the silver-loaded zirconium phosphate are connected by a chemical bridging of high-boiling-point small molecules (ethylene glycol). Simultaneously, due to the dissociation characteristics of the phosphate groups on the surface of the silver-loaded zirconium phosphate, its isoelectric point is 2.5~5.0, and it carries a negatively charged interfacial kinetic potential at pH=6~7. The nano-zinc oxide, due to the protonation of the hydroxyl groups on its surface, has an isoelectric point of 8~9, and it carries a positively charged interfacial kinetic potential at pH=6~7. Therefore, the silver-loaded zirconium phosphate and the nano-zinc oxide can be directionally assembled through electrostatic adsorption driven by Coulomb forces, forming a stable composite structure with the silver-loaded zirconium phosphate as the core and the nano-zinc oxide as the shell.

[0008] In the nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent prepared in this invention, a dual effect of photocatalysis and ion slow release can be formed. The reactive oxygen species (ROS) generated by the photocatalysis of nano-zirconia and the silver ions released by the silver-loaded zirconium phosphate form a synergistic pathway of "oxidative damage + membrane damage". The photogenerated electrons generated by nano-zirconia are captured by silver ions, allowing more photogenerated holes to participate in the dye degradation reaction, thereby enhancing the antibacterial efficiency and enabling the composite antibacterial agent to kill Gram-positive and Gram-negative bacteria (such as Escherichia coli and Staphylococcus aureus) with a broad spectrum. It is effective in both light and dark environments, covering antibacterial needs in all scenarios. Furthermore, by utilizing the specific shape of zirconium phosphate, coating its surface with nano-zirconia can limit the particle size of nano-zirconia and improve the dispersion stability of nano-zirconia in resin and other matrices. In addition, in the silver-loaded zirconium phosphate, silver exists in the intercalation of zirconium phosphate in ionic form, thus avoiding the problem of dark color in silver-based antibacterial agents, and can be used in light-colored textiles.

[0009] This invention utilizes the principles of colloidal hydrogen bonding and electrostatic self-assembly to composite ZnO with silver-loaded zirconium phosphate, eliminating the need for calcination and avoiding the abnormal growth of nano-zinc oxide during calcination. This results in a composite material with superior antibacterial properties. Furthermore, bridging ZnO and silver-loaded zirconium phosphate with ethylene glycol achieves the following effects: firstly, the hydroxyl groups in ethylene glycol form hydrogen bonds with the hydroxyl groups on the surfaces of ZnO and silver-loaded zirconium phosphate, which can regulate Ag... + With Zn 2+ Slow release and maintenance of effective antibacterial concentration achieve broad-spectrum synergistic antibacterial activity while ensuring a short interfacial distance between the two, promoting photogenerated electron transfer in ZnO and generating more reactive oxygen species, thus exerting a better antibacterial effect. On the other hand, the ethylene glycol carbon chain can form a spatial barrier, inhibiting ZnO aggregation, retaining a high specific surface area and active sites, while the hydroxyl groups promote ZnO aggregation through weak coordination. 2+ Released in the dark, it induces ZnO to generate oxygen vacancies to produce dark-state reactive oxygen species, thus compensating for its narrow light response range and giving the nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent better antibacterial properties.

[0010] Building upon this, before loading ZnO onto silver-loaded zirconium phosphate, the present invention first disperses the silver-loaded zirconium phosphate in ethylene glycol. This surface pretreatment of the silver-loaded zirconium phosphate enables in-situ nucleation of ZnO at specific sites on the surface of the silver-loaded zirconium phosphate during subsequent self-assembly, reducing nano-ZnO agglomeration and enhancing interfacial bonding. Furthermore, the method of the present invention can also control the orientation of ZnO crystal planes, preferentially exposing highly active crystal planes to enhance ROS generation.

[0011] Preferably, step S1 includes: adding an ethylene glycol solution of alkali dropwise into an ethylene glycol solution of zinc salt, and reacting at 60-120°C for 2-3 hours.

[0012] Preferably, in step S1, the molar ratio of the zinc salt to the alkali is 1:(1~10).

[0013] Preferably, the concentration of the zinc salt in the ethylene glycol solution is 0.25~3 mol / L; and the concentration of the alkali in the ethylene glycol solution is 1~8 mol / L.

[0014] Preferably, the ethylene glycol solution of the zinc salt also contains water, wherein the volume ratio of ethylene glycol to water is 10:0.5~1.

[0015] Preferably, in step S1, the zinc salt is zinc acetate and the alkali is sodium hydroxide.

[0016] Preferably, in step S2, the method of dispersing the silver-loaded zirconium phosphate into ethylene glycol is stirring and ultrasonic dispersion; the mass ratio of the silver-loaded zirconium phosphate to ethylene glycol is (1~5):10.

[0017] Preferably, in step S3, the mass ratio of ZnO to silver-loaded zirconium phosphate is 1:(11~20) based on zinc element.

[0018] Preferably, in step S3, the dropping rate of the ZnO-ethylene glycol dispersion into the silver-loaded zirconium phosphate dispersion is 0.05~1.2 mL / s.

[0019] Preferably, in step S3, the self-assembly process involves stirring at 60~120℃ for 40~80 min.

[0020] Preferably, in step S3, the process of separating the product includes: centrifuging to collect the precipitate, washing the precipitate, and drying it.

[0021] Compared with the prior art, the present invention has the following advantages: (1) In the nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent prepared by the present invention, the silver-loaded zirconium phosphate can reduce the aggregation of nano-zinc oxide, and the released silver ions can bind to the bacterial cell membrane and destroy the cell structure. It can synergize with the ROS effect of nano-zinc oxide, thereby enhancing the antibacterial efficiency, achieving a broad-spectrum bactericidal effect, and having a better bactericidal effect in both light and dark environments.

[0022] (2) This invention utilizes the principles of colloidal hydrogen bonding and electrostatic self-assembly to form a composite material by bridging ZnO and silver-loaded zirconium phosphate with ethylene glycol. This method can reduce the aggregation of nano-ZnO and also regulate Ag + and Zn 2+ Slow release and maintenance of effective antibacterial concentration, and expansion of the photoresponse range of nano-ZnO, thereby improving the antibacterial properties of the composite material.

[0023] (3) Before loading ZnO onto silver-loaded zirconium phosphate, the present invention first disperses the silver-loaded zirconium phosphate in ethylene glycol, which enables in-situ nucleation of ZnO at specific sites on the surface of the silver-loaded zirconium phosphate, reduces the aggregation of nano ZnO and enhances the interfacial bonding, thereby further improving the antibacterial properties of the composite material. Attached Figure Description

[0024] Figure 1 This is a scanning electron microscope image of the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent prepared in Example 2.

[0025] Figure 2 This is a scanning electron microscope image of the nano-zinc oxide prepared in Example 1.

[0026] Figure 3 These are scanning electron microscope (SEM) images of the silver-loaded zirconium phosphate used in the various embodiments and comparative examples.

[0027] Figure 4 This is the particle size distribution curve of the zinc oxide / silver-loaded zirconium phosphate-ethylene glycol dispersion prepared in Example 2.

[0028] Figure 5 This is an X-ray diffraction pattern of nano zinc oxide, silver-loaded zirconium phosphate (Ag-ZrP), and zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent (ZnO / Ag-ZrP) in Example 2.

[0029] Figure 6 This is the curve showing the change in absorbance of Rhodamine B under ultraviolet light over time for nano zinc oxide and zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent (ZnO / Ag-ZrP) in Example 2.

[0030] Figure 7 The image shows the UV-Vis absorption spectrum of the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent prepared in Example 2.

[0031] Figure 8 This is a comparison of the antibacterial effects of nano zinc oxide, silver-loaded zirconium phosphate (Ag-ZrP), and zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent (ZnO / Ag-ZrP) after 15 min of shaking contact culture with bacteria in Example 2. Detailed Implementation

[0032] The present invention will be further described below with reference to embodiments.

[0033] A method for self-assembling a nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent, comprising the following steps: S1: Nano-ZnO is generated in ethylene glycol by reacting zinc salt with alkali to obtain ZnO-ethylene glycol dispersion; S2: Disperse silver-loaded zirconium phosphate in ethylene glycol to obtain a silver-loaded zirconium phosphate dispersion; S3: Add ZnO-ethylene glycol dispersion to silver-loaded zirconium phosphate dispersion, and allow self-assembly to occur at pH 6-7. Separate the product to obtain nano ZnO / silver-loaded zirconium phosphate composite antibacterial agent.

[0034] In the above preparation method, the conformal coating of nano-zinc oxide and silver-loaded zirconium phosphate is achieved by utilizing the principles of colloidal hydrogen bonding and electrostatic self-assembly. Specifically, by synthesizing nano-zinc oxide in ethylene glycol, hydrogen bonds can be formed between the hydroxyl groups in ethylene glycol and the surface of nano-zinc oxide. During the assembly process, another hydroxyl group in the ethylene glycol molecule forms a hydrogen bond with the silver-loaded zirconium phosphate. The nano-zinc oxide and the silver-loaded zirconium phosphate are connected by a chemical bridge of high-boiling-point small molecules (ethylene glycol). At the same time, due to the dissociation characteristics of the phosphate groups on the surface of the silver-loaded zirconium phosphate, its isoelectric point is 2.5~5.0, and it carries a negatively charged interfacial kinetic potential at pH=6~7. The nano-zinc oxide, due to the protonation of the hydroxyl groups on its surface, has an isoelectric point of 8~9, and it carries a positively charged interfacial kinetic potential at pH=6~7. Therefore, the silver-loaded zirconium phosphate and the nano-zinc oxide can be directionally assembled through electrostatic adsorption driven by Coulomb forces to form a stable composite structure with the silver-loaded zirconium phosphate as the core and the nano-zinc oxide as the shell.

[0035] In some specific embodiments, step S1 includes: adding an ethylene glycol solution of an alkali dropwise to an ethylene glycol solution of a zinc salt, and reacting at 60-120°C for 2-3 hours. The concentration of the ethylene glycol solution of the zinc salt is 0.25-3 mol / L; the concentration of the ethylene glycol solution of the alkali is 1-8 mol / L. The ethylene glycol solution of the zinc salt also contains water, wherein the volume ratio of ethylene glycol to water is 10:0.5-1.

[0036] In some specific embodiments, in step S1, the molar ratio of the zinc salt to the alkali is 1:(1~10).

[0037] In some specific embodiments, in step S1, the zinc salt is zinc acetate; and the alkali is sodium hydroxide.

[0038] In some specific embodiments, in step S2, the method of dispersing the silver-loaded zirconium phosphate into ethylene glycol is stirring and ultrasonic dispersion; the mass ratio of the silver-loaded zirconium phosphate to ethylene glycol is (1~5):10.

[0039] In some specific embodiments, in step S3, the mass ratio of ZnO to silver-loaded zirconium phosphate is 1:(11~20) based on zinc element.

[0040] In some specific embodiments, in step S3, the dropping rate of the ZnO-ethylene glycol dispersion into the silver-loaded zirconium phosphate dispersion is 0.05~1.2 mL / s.

[0041] In some specific embodiments, in step S3, the self-assembly process involves stirring at 60~120℃ for 40~80 minutes.

[0042] In some specific embodiments, step S3, the process of separating the product includes: centrifuging to collect the precipitate, washing the precipitate, and drying it.

[0043] The present invention will now be described through specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0044] Example 1: Preparation of nano zinc oxide Nano-zinc oxide was synthesized in ethylene glycol according to the following steps: 4.59 g of zinc acetate was weighed and dissolved in 50 mL of ethylene glycol, and 5 mL of deionized water was added to aid dissolution, yielding a zinc acetate solution. 2 g of sodium hydroxide was weighed and dissolved in 50 mL of ethylene glycol, yielding a sodium hydroxide solution. The sodium hydroxide solution was then slowly added dropwise to the zinc acetate solution at a rate of 1.2 mL / s, and the reaction was carried out at 80 °C with a stirring speed of 600 rpm for 2.0 h. After the reaction was complete, the solution was ultrasonically dispersed in an ultrasonic bath for 30 min to obtain a zinc oxide-ethylene glycol dispersion.

[0045] The scanning electron microscope image of the nano-zinc oxide obtained in this embodiment is as follows: Figure 2 As shown, the particle size of the nano zinc oxide is about 15 nm, and it has good dispersibility.

[0046] Example 2: Preparation of nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent The following steps were followed to prepare a self-assembled nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent: S1: Preparation of zinc oxide-ethylene glycol dispersion 9.173 g of zinc acetate was weighed and dissolved in 50 mL of ethylene glycol, and 5 mL of deionized water was added to aid dissolution, yielding a zinc acetate solution. 4 g of sodium hydroxide was weighed and dissolved in 50 mL of ethylene glycol, yielding a sodium hydroxide solution. Subsequently, the sodium hydroxide solution was slowly added dropwise to the zinc acetate solution at a rate of 1.2 mL / s, and the reaction was carried out at 60 °C with a stirring speed of 600 rpm for 2.0 h. After the reaction was completed, the solution was ultrasonically dispersed in an ultrasonic bath for 30 min to obtain a zinc oxide-ethylene glycol dispersion.

[0047] S2: Preparation of composite antibacterial agents 10 g of silver-loaded zirconium phosphate (commercially available, SEM image as shown) was used. Figure 3As shown, the silver-loaded zirconium phosphate (which has a regular cubic morphology and relatively uniform particle size, at the submicron scale) was dispersed in 100 mL of ethylene glycol by stirring and ultrasonication to obtain a silver-loaded zirconium phosphate dispersion. The zinc oxide-ethylene glycol dispersion obtained in step S1 was added dropwise to the silver-loaded zirconium phosphate dispersion at a rate of 1.0 mL / s, and the pH of the system was adjusted and maintained at 6-7. The mixture was stirred and reacted at 80℃ for 80 min to obtain a zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent-ethylene glycol dispersion. The zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent-ethylene glycol dispersion was centrifuged, washed until neutral, and dried to obtain the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent.

[0048] The SEM image of the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent prepared in this embodiment is as follows: Figure 1 As shown. With Figure 3 In contrast to the silver-loaded zirconium phosphate, it can be seen that Figure 1 The particles in the study were covered with fine zinc oxide nanostructures, which made the originally relatively regular cubic surface rough and produced island-like and granular protrusions. No free zinc oxide nanocrystals or uncoated silver-loaded zirconium phosphate were observed, indicating that the two formed a strong chemical bond.

[0049] The particle size distribution curve of the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent-ethylene glycol dispersion prepared in this embodiment is as follows: Figure 4 As shown, the average particle size of the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent is approximately 750 nm, with a narrow particle size distribution. No size distribution corresponding to 15 nm zinc oxide was observed.

[0050] In this embodiment, the XRD patterns of nano-zinc oxide, the silver-loaded zirconium phosphate (Ag-ZrP) used in step S2, and the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent (ZnO / Ag-ZrP) prepared in step S2 are as follows: Figure 5 As shown, the composite antibacterial agent prepared in this embodiment contains two phases: zinc oxide and silver-loaded zirconium phosphate.

[0051] In this embodiment, the photocatalytic degradation performance of Rhodamine B by the nano-zinc oxide prepared in step S1 and the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent (ZnO / Ag-ZrP) prepared in step S2 is as follows: Figure 6As shown. The detection method for the photocatalytic degradation performance of the sample is as follows: 200 mL of 30 mg / L Rhodamine B solution was prepared, and 100 mg of the sample to be tested was added; firstly, the reaction system was placed in a dark environment for a 30 min dark adsorption experiment; then, the reaction system was irradiated under a 20 W, 365 nm UV lamp, and sampling was performed every 6 min; the sample was centrifuged to remove nanoparticles; finally, the absorbance of Rhodamine B in the supernatant was measured using a UV-Vis infrared spectrometer. Figure 6 The results show that, compared with nano zinc oxide, the photocatalytic degradation efficiency of the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent is significantly improved. This is because the photogenerated electrons generated by nano zinc oxide are captured by silver ions, and more photogenerated holes participate in the dye degradation reaction. It also indirectly indicates that the composite antibacterial agent can generate more reactive oxygen free radicals, which helps to improve its antibacterial performance.

[0052] The UV-Vis absorption spectrum of the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent prepared in this embodiment is as follows: Figure 7 As shown, the composite antibacterial agent exhibits significant absorption in the 300-400 nm ultraviolet band, corresponding to the intrinsic absorption of nano-zinc oxide itself. Meanwhile, since the silver-loaded zirconium phosphate contains not only silver ions but also elemental silver nanoparticles, it produces weak absorption in the visible light region (400-600 nm) due to the local surface plasmon resonance effect, which broadens the photoresponse range to a certain extent.

[0053] In this embodiment, the antibacterial test results of nano zinc oxide, silver-loaded zirconium phosphate (Ag-ZrP) used in step S2, and the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent (ZnO / Ag-ZrP) prepared in step S2 are as follows: Figure 8 As shown in Table 1. The detection method for the photocatalytic degradation performance of the samples refers to Appendix A, the oscillation method, of the national standard GB / T 21510-2024 "Test Methods and Evaluation of Antibacterial Properties of Nano-Inorganic Materials". The specific operation is as follows: (1) Activation of bacterial strains: In a clean bench, use an inoculation loop to inoculate Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) onto nutrient agar slants and place them in a constant temperature incubator at 37°C for 18-24 hours to obtain the second-generation bacterial strains. Take one loopful of the second-generation activated bacterial strains and inoculate them onto nutrient agar slants using the above method, and incubate them at 37°C for 18-24 hours to obtain the third-generation bacterial strains.

[0054] (2) Preparation of bacterial suspension: Take the activated bacterial strain and add it to a sterilized conical flask containing an appropriate amount of PBS buffer. Mix well to prepare a suspension with a concentration of 1×10⁻⁶. 5 ~5×10 5A bacterial suspension of cfu / mL.

[0055] (3) Preparation of sample solution: Add 0.5 g of control sample, Ag-ZrP, ZnO, and ZnO / Ag-ZrP to four Erlenmeyer flasks, each containing 95 mL of phosphate buffer containing 0.1% (mass fraction) Tween-80, and then add 5 mL of bacterial suspension.

[0056] (4) "0" contact time viable count: Before shaking, take 1 mL of control sample solution and count it to determine whether the concentration of bacterial suspension meets the requirements.

[0057] (5) Shaking contact culture: Place all sample solutions on a constant temperature shaker and shake contact culture at 37℃ with a rotation speed of 150 r / min. Select a shaking contact culture time of 15 min (all under natural light conditions).

[0058] (6) Viable bacteria count after shaking for a certain period of time: After shaking, take 1 mL of bacterial suspension from each sample solution and dilute it 10 times to the appropriate concentration. Use a pipette to take 0.1 mL and drop it onto the surface of the solidified beef extract peptone agar medium plate. Spread it evenly with a sterile glass rod. Inoculate two culture dishes in parallel for each sample solution. Cover the culture dishes and then invert them and place them in a 37℃ constant temperature incubator for 18~24 h.

[0059] (7) Antibacterial rate (R) calculation: The average number of bacteria recovered after the control sample was in contact with the test bacteria for 15 min (in CFU / mL) was recorded as A, and the average number of bacteria recovered after the test sample was in contact with the test bacteria for 15 min (in CFU / mL) was recorded as B. The antibacterial rate (R) was calculated according to (AB) / A×100%.

[0060] Repeat the above method three times and take the average of the three experiments.

[0061] Figure 8 As shown in Table 1, the zinc oxide / silver-loaded zirconium phosphate complex exhibited superior antibacterial activity against Escherichia coli and Staphylococcus aureus within 15 minutes compared to both silver-loaded zirconium phosphate and nano zinc oxide.

[0062] Table 1. Antibacterial rates of different antibacterial agents against Staphylococcus aureus and Escherichia coli Antibacterial agents R (E. coli) R (S. aureus) Ag-ZrP 88.8% 60.6% ZnO 61.2% 63.6% ZnO / Ag-ZrP >99.9% >99.9% Example 3: Preparation of Nano-ZnO / Silver-loaded Zirconium Phosphate Composite Antibacterial Agent The following steps were followed to prepare a self-assembled nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent: S1: Preparation of zinc oxide-ethylene glycol dispersion 9.173 g of zinc acetate was weighed and dissolved in 50 mL of ethylene glycol, and 2.5 mL of deionized water was added to aid dissolution, yielding a zinc acetate solution. 8 g of sodium hydroxide was weighed and dissolved in 25 mL of ethylene glycol, yielding a sodium hydroxide solution. Subsequently, the sodium hydroxide solution was slowly added dropwise to the zinc acetate solution at a rate of 0.5 mL / s, and the reaction was carried out at 80 °C with a stirring speed of 800 rpm for 2.0 h. After the reaction was complete, the solution was ultrasonically dispersed in an ultrasonic bath for 30 min to obtain a zinc oxide-ethylene glycol dispersion.

[0063] S2: Preparation of composite antibacterial agents 10 g of silver-loaded zirconium phosphate (commercially available, SEM image as shown) was used. Figure 3 As shown, the silver-loaded zirconium phosphate (which has a regular cubic morphology and relatively uniform particle size, at the submicron scale) was dispersed in 100 mL of ethylene glycol by stirring and ultrasonication to obtain a silver-loaded zirconium phosphate dispersion. The zinc oxide-ethylene glycol dispersion prepared in step S1 was added dropwise to the silver-loaded zirconium phosphate dispersion at a rate of 1.2 mL / s. The pH of the system was adjusted and maintained at 6-7, and the reaction was carried out by stirring at 80 °C for 80 min. The resulting product was centrifuged, washed until neutral, and dried to obtain a zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent.

[0064] Following the method in Example 2, the antibacterial properties of the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent prepared in this example were tested, and it was found that its antibacterial rate against Escherichia coli and Staphylococcus aureus was >99.9% within 15 minutes.

[0065] Example 4: Preparation of Nano-ZnO / Silver-loaded Zirconium Phosphate Composite Antibacterial Agent The following steps were followed to prepare a self-assembled nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent: S1: Preparation of zinc oxide-ethylene glycol dispersion 18.346 g of zinc acetate was weighed and dissolved in 50 mL of ethylene glycol, and 5 mL of deionized water was added to aid dissolution, yielding a zinc acetate solution. 4 g of sodium hydroxide was weighed and dissolved in 50 mL of ethylene glycol, yielding a sodium hydroxide solution. Subsequently, the sodium hydroxide solution was slowly added dropwise to the zinc acetate solution at a rate of 1.0 mL / s, and the reaction was carried out at 70 °C with a stirring speed of 800 rpm for 2.0 h. After the reaction was completed, the solution was ultrasonically dispersed in an ultrasonic bath for 30 min to obtain a zinc oxide-ethylene glycol dispersion.

[0066] S2: Preparation of composite antibacterial agents 30 g of silver-loaded zirconium phosphate (commercially available, SEM image as shown) was used. Figure 3As shown, the silver-loaded zirconium phosphate (which has a regular cubic morphology and relatively uniform particle size, at the submicron scale) was dispersed in 600 mL of ethylene glycol by stirring and ultrasonication to obtain a silver-loaded zirconium phosphate dispersion. The zinc oxide-ethylene glycol dispersion prepared in step S1 was added dropwise to the silver-loaded zirconium phosphate dispersion at a rate of 1.0 mL / s, and the pH of the system was adjusted and maintained at 6-7. The reaction was stirred at 80 °C for 80 min. The resulting product was centrifuged, washed until neutral, and dried to obtain a zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent.

[0067] Following the method in Example 2, the antibacterial properties of the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent prepared in this example were tested, and it was found that its antibacterial rate against Escherichia coli and Staphylococcus aureus was >99.9% within 15 minutes.

[0068] Comparative Example 1: Preparation of Nano-ZnO / Silver-loaded Zirconium Phosphate Composite Antibacterial Agent The only difference between this comparative example and Example 2 is that the composite of nano-ZnO and silver-loaded zirconium phosphate is achieved according to the method described in patent CN119791133A. Specifically, this comparative example prepares the nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent according to the following steps: S1: Preparation of nano-zinc oxide 9.173 g of zinc acetate was weighed and dissolved in 50 mL of ethylene glycol, with 5 mL of deionized water added to aid dissolution, yielding a zinc acetate solution. 4 g of sodium hydroxide was weighed and dissolved in 50 mL of ethylene glycol, yielding a sodium hydroxide solution. Subsequently, the sodium hydroxide solution was slowly added dropwise to the zinc acetate solution at a rate of 1.2 mL / s, and the reaction was carried out at 60 °C with a stirring speed of 600 rpm for 2.0 h. After the reaction was complete, the precipitate was collected by centrifugation, washed twice with water, and dried to obtain nano-zinc oxide.

[0069] S2: Preparation of composite antibacterial agents The nano-zinc oxide obtained in step S1 was dispersed in deionized water, stearic acid and sodium dodecyl sulfate were added, and the mixture was stirred for 5 min. Then, 10 g of silver-loaded zirconium phosphate (commercially available, SEM image as shown) was added. Figure 3 As shown, the silver-loaded zirconium phosphate exhibits a regular cubic morphology with relatively uniform particle size (submicron scale). After stirring for 45 min, a mixed solution was obtained, in which the mass fractions of nano-zinc oxide, stearic acid, and sodium dodecyl sulfate were 2%, 0.2%, and 0.3%, respectively. The mixed solution was filtered, the resulting precipitate was dried, and calcined at 600℃ for 3 h to obtain the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent.

[0070] Following the method in Example 2, the antibacterial properties of the zinc oxide / silver-loaded zirconium phosphate composite antibacterial agent prepared in this comparative example were tested. The antibacterial rates against *Escherichia coli* and *Staphylococcus aureus* were measured to be 95.2% and 93.1%, respectively, after 15 minutes. The antibacterial rate test results showed that the antibacterial performance of the composite material prepared in this comparative example was significantly lower than that in Example 2. The reason for this is that during the calcination process in Comparative Example 1, nano-zinc oxide is prone to abnormal growth, resulting in a weakened antibacterial effect, while Example 2 does not require a calcination process. Furthermore, in Example 2, ZnO and silver-loaded zirconium phosphate are bridged by ethylene glycol. On the one hand, the hydroxyl groups in ethylene glycol form hydrogen bonds with the hydroxyl groups on the surface of ZnO and silver-loaded zirconium phosphate, which can regulate the Ag... + With Zn 2+ Slow release and maintenance of effective antibacterial concentration achieve broad-spectrum synergistic antibacterial activity while ensuring a short interfacial distance between the two, promoting photogenerated electron transfer in ZnO and generating more reactive oxygen species, thus exerting a better antibacterial effect. On the other hand, the ethylene glycol carbon chain can form a spatial barrier, inhibiting ZnO aggregation, retaining a high specific surface area and active sites, while the hydroxyl groups promote ZnO aggregation through weak coordination. 2+ Released in the dark, it induces ZnO to generate oxygen vacancies to produce dark-state reactive oxygen species, thus compensating for its narrow light response range and giving the nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent better antibacterial properties.

Claims

1. A method for self-assembling a nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent, characterized in that the steps include... include: S1: Nano-ZnO is generated in ethylene glycol by reacting zinc salt with alkali to obtain ZnO-ethylene glycol dispersion; S2: Disperse silver-loaded zirconium phosphate in ethylene glycol to obtain a silver-loaded zirconium phosphate dispersion; S3: Add ZnO-ethylene glycol dispersion to silver-loaded zirconium phosphate dispersion, and allow self-assembly to occur at pH 6-7. Separate the product to obtain nano ZnO / silver-loaded zirconium phosphate composite antibacterial agent.

2. The method according to claim 1, characterized in that, The specific process of step S1 includes: adding the ethylene glycol solution of the alkali dropwise into the ethylene glycol solution of the zinc salt, and reacting at 60~120℃ for 2~3 h.

3. The method according to claim 1 or 2, characterized in that, In step S1, the molar ratio of the zinc salt to the alkali is 1:(1~10).

4. The method according to claim 2, characterized in that, The concentration of the zinc salt in the ethylene glycol solution is 0.25~3 mol / L; the concentration of the alkali in the ethylene glycol solution is 1~8 mol / L.

5. The method according to claim 2 or 4, characterized in that, The zinc salt ethylene glycol solution also contains water, wherein the volume ratio of ethylene glycol to water is 10:0.5~1.

6. The method according to claim 1 or 2, characterized in that, In step S1, the zinc salt is zinc acetate; the alkali is sodium hydroxide.

7. The method according to claim 1, characterized in that, In step S2, the method of dispersing silver-loaded zirconium phosphate into ethylene glycol is stirring and ultrasonic dispersion; the mass ratio of silver-loaded zirconium phosphate to ethylene glycol is (1~5):

10.

8. The method according to claim 1, characterized in that, In step S3, the mass ratio of Zn to silver-loaded zirconium phosphate in the nano-ZnO / silver-loaded zirconium phosphate composite antibacterial agent is 1:(11~20).

9. The method according to claim 1, characterized in that, In step S3, the ZnO-ethylene glycol dispersion is added to the silver-loaded zirconium phosphate dispersion at a dropping rate of 0.05~1.2 mL / s.

10. The method according to claim 1, characterized in that, In step S3, the self-assembly process involves stirring at 60~120℃ for 40~80 min.

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