A BiO 2-x @Fe composite nanomaterial preparation method and its application in antibacterial field

Abstract

The application relates to a BiO 2‑x @Fe composite nanomaterial preparation method and application thereof in the antibacterial field. The nanomaterial contains rich oxygen defect sites, can realize electron capture and separation, reduces the recombination of photo-generated electrons and holes, and promotes the generation of photo-catalytic active oxygen free radicals; the surface-loaded macromolecular substance PVP improves the water dispersibility and biocompatibility of the nanoparticles, and simultaneously strengthens the adsorption of the nanomaterial on the bacterial surface, thereby providing a good foundation for realizing better antibacterial capacity; the loaded Fe ions help to form a Fenton reaction in water to improve the photo-catalytic active oxygen free radical generation capacity; the nanomaterial has unique near-infrared light absorption capacity, exhibits effective photothermal reaction after light absorption, improves the local water molecular thermal motion, makes the electrons more fully interact with water molecules to accelerate the generation of active oxygen free radicals, further enhances the catalytic activity, and finally realizes high-efficiency antibacterial effect.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic antibacterial materials technology, specifically to a BiO2 material. 2-x Preparation methods of Fe composite nanomaterials and their application in the field of antibacterial agents. Background Technology

[0002] In recent years, with the rapid expansion of urban industrial and residential areas, bacterial pollution in water bodies has become an increasingly serious problem. Since the late 17th century, humanity has been exploring and combating bacteria. Early antibacterial methods, based on penicillin antibiotics first discovered by bacteriologist Alexander Fleming, provided a good approach to antibacterial treatment and were considered the most effective method for treating pathogens. However, with the excessive clinical use of antibiotics, bacterial resistance has increased dramatically, weakening or even eliminating the effectiveness of this back-end treatment-based approach. Therefore, finding a highly effective antibacterial method that can overcome drug resistance has become a crucial issue in the field of antibacterial medicine.

[0003] Reactive oxygen species, such as hydroxyl radicals (·OH) and superoxide radicals (·O2), are generated by semiconductor photocatalytic nanomaterials. - This material possesses strong oxidizing and reducing properties, allowing it to penetrate cell walls and disrupt cell membranes, thereby effectively killing bacteria. Applying this material to environmental wastewater antibacterial treatment can control the number of bacteria in water at its source. Compared to environmental antibacterial methods such as chlorination and ultraviolet irradiation, it does not require active external energy input, making it a promising front-end water antibacterial method. However, due to problems such as poor visible light response, easy recombination of photogenerated carriers, and high charge migration resistance, the application of photocatalytic technology in environmental antibacterial treatment remains limited.

[0004] Among numerous photocatalytic nanomaterial systems, BiO2 nanomaterials have attracted widespread attention and research in recent years due to their unique atomic structure, excellent optical properties, low manufacturing cost, and good biocompatibility. However, BiO2 with its single structure and morphology only has ultraviolet and partial visible light absorption capabilities, and its near-infrared light absorption capability is poor. This seriously hinders the light absorption and utilization efficiency of solar energy and is not conducive to the sterilization application of nanomaterials under natural conditions.

[0005] Therefore, in order to enhance the antibacterial application potential of BiO2 nanomaterials, it is of great significance to construct a reasonable and effective BiO2 nanomaterial through effective regulation. Summary of the Invention

[0006] The purpose of this invention is to provide a spherical oxygen-deficient bismuth-based composite nanomaterial with relatively uniform morphology and surface loading of PVP and Fe. This nanomaterial can absorb more light energy, has relatively good biocompatibility, more effective surface adsorption capacity and higher reactive oxygen free radical yield, thereby achieving highly efficient antibacterial properties.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A BiO 2-x @Fe composite nanomaterials, comprising internal nanospheres and a surface structure supported on the surface of the internal nanospheres; the internal nanospheres are oxygen-deficient BiO. 2-x Nanospheres, wherein 0 < x < 0.5; the surface structure comprises PVP and Fe.

[0009] The BiO provided by this invention 2-x In Fe composite nanomaterials, the central nanospheres are single compounds containing oxygen vacancies, namely BiO. 2-x By using BiO 2-x Using this substrate, light absorption in the visible light region was achieved, improving its near-infrared light absorption characteristics compared to wide-bandgap nanomaterials. Simultaneously, oxygen defects also contribute to improving the photogenerated hole and electron separation performance of traditional BiO2 semiconductors.

[0010] In BiO 2-x The PVP coating on the surface of the Fe composite nanomaterial further enhances the dispersibility and biocompatibility of the nanomaterial in water. It can also serve as a bridging layer to modify nanoparticles or as a second shell by chemically linking amino acids and / or other corresponding functional compounds to further improve particle properties and enhance their application performance.

[0011] In BiO 2-x The Fe coating on the surface of the @Fe composite nanomaterial provides Fenton reaction sites, which helps to achieve a more efficient photocatalytic reactive oxygen free radical yield and improve the antibacterial properties of the environment.

[0012] Furthermore, the BiO provided by the present invention 2-x @Fe composite nanomaterials exhibit a relatively uniform particle size distribution, with a morphology that is basically spherical, and an average particle size of 250–350 nm.

[0013] Furthermore, the average molecular weight of the PVP described in this invention can be 5,000 to 30,000, and the PVP includes, but is not limited to, its derivatives, such as amino or carboxylated PVP.

[0014] Another object of the present invention is to provide a simple, convenient and quick BiO 2-xA method for preparing Fe composite nanomaterials, the method comprising the following steps:

[0015] Bi(NO3)3·5H2O and PVP were dissolved in anhydrous ethanol, ethylene glycol was added, and the mixture was ultrasonically vibrated for 10 min to ensure homogeneity. The mixture was then transferred to a reaction vessel and reacted at 160℃ for 6 h. After natural cooling to room temperature, the solution was washed and centrifuged to obtain a Bi2O3 suspension. A 5 mg / mL Bi2O3 suspension was prepared, and a 1 mg / mL FeCl3 solution was added. After stirring for 20 min, a 1 mg / mL NaBH4 solution was added, and stirring continued until a black mixture was formed. The mixture was then centrifuged and dried to obtain BiO2. 2-x @Fe composite nanomaterials.

[0016] Furthermore, the molar ratio of Bi(NO3)3·5H2O to PVP is 20:27.

[0017] Furthermore, during the centrifugation process, the centrifugation speed is 8000-10000 rpm.

[0018] Furthermore, deionized water is preferred for preparing the solution or as the reaction medium, and the reaction products can also be washed several times with deionized water and / or 75% ethanol to remove any impurities.

[0019] Another object of the present invention is to provide such BiO 2-x The application of @Fe composite nanomaterials in the field of environmental antibacterial, wherein the application is as a photocatalyst for any one or more of the following technologies: environmental water treatment, urban sewage treatment, and medical wastewater treatment.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. This invention provides a BiO 2-x @Fe composite nanomaterials are suitable for photocatalytic antibacterial activity with broad-spectrum light absorption response. Compared with traditional antibiotics, they do not produce drug resistance, reduce the secondary pollution problems caused by antibiotics, and reduce the active external energy input.

[0022] 2. This nanomaterial contains abundant oxygen defect sites, enabling electron capture and separation, reducing the recombination of photogenerated electrons and holes, and promoting the generation of photocatalytic reactive oxygen species. The surface-loaded macromolecular material PVP improves the water dispersibility and biocompatibility of the nanoparticles, while also enhancing the BiO2 content. 2-x The adsorption capacity of Fe composite nanomaterials on bacterial surfaces provides a good foundation for better antibacterial capabilities; the loaded Fe ions help to form a Fenton reaction in water to enhance the photocatalytic generation of reactive oxygen species; the constructed BiO... 2-x@Fe composite nanomaterials have unique near-infrared light absorption capabilities. After absorbing light, they exhibit effective photothermal reactions, which enhance the local thermal motion of water molecules. This allows their electrons to interact more fully with water molecules, accelerating the generation of reactive oxygen free radicals, further enhancing catalytic activity, and ultimately achieving highly efficient antibacterial effects.

[0023] 3. This material possesses the advantages of nanomaterials, and its corresponding outer structure can endow it with different functions, providing convenience for multimodal and efficient antibacterial applications. With more functions, it has greater potential for application in the field of environmental antibacterial. Compared with existing nanomaterials, this material has a simple and convenient preparation method, mild reaction conditions, inexpensive raw materials, good biological properties, and can be synthesized in large quantities without high costs and complex processes.

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, technical features and beneficial effects of the present invention more obvious and understandable, the following preferred embodiments are described in detail with reference to the accompanying drawings. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 BiO in Embodiment 1 of the present invention 2-x Scanning electron microscope image of Fe composite nanomaterials;

[0027] Figure 2 BiO in Embodiment 1 of the present invention 2-x Transmission electron microscope image of Fe composite nanomaterials;

[0028] Figure 3 BiO in Embodiment 1 of the present invention 2-x TEM lattice spacing diagram of Fe composite nanomaterials;

[0029] Figure 4 BiO in Embodiment 1 of the present invention 2-x X-ray energy dispersive spectroscopy elemental imaging analysis of Fe composite nanomaterials;

[0030] Figure 5 BiO in Embodiment 1 of the present invention 2-x and BiO 2-xX-ray diffraction comparison of Fe;

[0031] Figure 6 BiO in Embodiment 1 of the present invention 2-x Ultraviolet absorption spectrum of Fe composite nanomaterials;

[0032] Figure 7 BiO in Embodiment 1 of the present invention 2-x Infrared spectrum of Fe composite nanomaterials;

[0033] Figure 8 BiO in Embodiment 2 of the present invention 2-x Scanning electron microscope image of the antibacterial effect of Fe composite nanomaterials;

[0034] Figure 9 BiO in Embodiment 2 of the present invention 2-x and BiO 2-x Comparison of bacterial culture dish results for @Fe. Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments to make its features and advantages clearer. However, it should be noted that the embodiments are for understanding the concept of the invention, and the scope of the invention is not limited to the embodiments listed herein. The technical solution of the present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0037] Example 1

[0038] 2 mmol of Bi(NO3)3·5H2O and 0.3 g of PVP were dissolved in 20 mL of anhydrous ethanol, and 25 mL of ethylene glycol were added. The mixture was ultrasonically vibrated for 10 min to ensure homogeneity, then transferred to a 50 mL reactor and reacted at 160 °C for 6 h. After natural cooling to room temperature, the resulting suspension after washing and centrifugation was Bi2O3. 30 mL of a 5 mg / mL Bi2O3 suspension was prepared, and 1 mg / mL FeCl3 was added. After stirring for 20 min, 5 mL of a 1 mg / mL NaBH4 solution was added, and stirring continued until a black mixture was formed. The mixture was then centrifuged and dried to obtain BiO2. 2-x @Fe composite nanomaterials;

[0039] The BiO 2-x The scanning electron microscope and transmission electron microscope results of Fe composite nanomaterials are as follows: Figure 1 and Figure 2 As shown, the synthesized BiO 2-x The average particle size of the Fe composite nanomaterials is relatively uniform, ranging from approximately 250 to 350 nm.

[0040] To further analyze its lattice characteristics, BiO 2-x Transmission electron microscopy results of Fe composite nanomaterials are as follows: Figure 3 As shown, it is proven that its main structure is composed of BiO. 2-x constitute.

[0041] BiO 2-x X-ray energy dispersive spectroscopy elemental analysis results of Fe composite nanomaterials are as follows: Figure 4 As observed, the constituent elements include Bi, O, Fe, N, and C, indicating that BiO 2-x The surface structure of the Fe composite nanomaterial contains PVP and Fe.

[0042] Further analysis of its chemical structure and composition using X-ray diffraction yielded the following results: Figure 5 As shown, the chemical structure of the synthesized nanoparticles was determined to be BiO. 2-x @Fe.

[0043] BiO 2-x The light absorption properties of Fe composite nanomaterials are as follows: Figure 6 As shown, the absorption range extends from visible light to near-infrared light, indicating that BiO2... 2-x @Fe composite nanomaterials have good light absorption capabilities and can also achieve photocatalytic activity under near-infrared light irradiation.

[0044] For the synthesis of BiO 2-x The surface molecular structure properties of Fe composite nanomaterials were studied, such as... Figure 7 As shown, the surface partial group strength and position are slightly shifted, indicating the effective functional group loading of Fe.

[0045] Example 2

[0046] The BiO obtained above 2-x The Fe composite nanomaterial was used in an antibacterial experiment involving photothermal conversion combined with photocatalysis, with Escherichia coli as the bacteria used. The selected laser wavelength was 808nm near-infrared light, and the selected BiO₂... 2-x The concentration of the Fe composite nanomaterial was 0.2 mg / mL. The laser power density used in the experiment was approximately 1.5 W / cm². 2 The irradiated field area is approximately 0.5 cm². 2 The irradiation time is about 10 minutes.

[0047] The experimental results were observed directly using an electron microscope, such as... Figure 8As shown, under near-infrared light alone, bacteria grow normally, their structure remains largely intact, and there is no large-scale bacterial death. However, when BiO2 is added... 2-x After co-incubation with Fe composite nanomaterials and cultivation under near-infrared light, the bacterial structure was extensively destroyed, indicating that the material has a significant antibacterial effect under light irradiation, leading to bacterial death.

[0048] Further antibacterial experiments were conducted. Figure 9 The image shows the optical results of *E. coli* treated with different methods in solid LB medium. The results show that in the control group under single light exposure, colonies formed abundantly, and the bacteria grew rapidly, almost covering the entire culture area. For BiO2... 2-x In the photocatalytically treated experimental group, colony growth was slightly inhibited. For the group with BiO₂… 2-x In the Fe photocatalyst experimental group, a significant reduction in bacterial colonies and a marked inhibition of bacterial growth were observed, demonstrating a good antibacterial effect.

[0049] In summary, this invention provides a BiO 2-x @Fe composite nanomaterials are suitable for broad-spectrum photocatalytic antibacterial activity, exhibiting no drug resistance compared to traditional antibiotics, reducing secondary pollution issues associated with antibiotics, and minimizing active external energy input. These nanomaterials contain abundant oxygen defect sites, enabling electron capture and separation, reducing the recombination of photogenerated electrons and holes, and promoting the generation of photocatalytic reactive oxygen species. The surface-loaded macromolecular material PVP improves the water dispersibility and biocompatibility of the nanoparticles, while also enhancing the BiO2 content. 2-x The adsorption capacity of Fe composite nanomaterials on bacterial surfaces provides a good foundation for better antibacterial capabilities; the loaded Fe ions help to form a Fenton reaction in water to enhance the photocatalytic generation of reactive oxygen species; the constructed BiO... 2-x @Fe composite nanomaterials possess unique near-infrared light absorption capabilities, exhibiting effective photothermal reactions after light absorption. This enhances the local thermal motion of water molecules, allowing their electrons to interact more fully with water molecules, accelerating the generation of reactive oxygen free radicals, further enhancing catalytic activity, and ultimately achieving highly efficient antibacterial effects. This material leverages the advantages of nanomaterials; its corresponding outer structure can impart different functions, facilitating multimodal and highly efficient antibacterial applications. Its enhanced functionality makes it more promising for use in environmental antibacterial fields. Compared to existing nanomaterials, this material's preparation method is simple and convenient, with mild reaction conditions, inexpensive raw materials, and good biological properties. It can be synthesized in large quantities without high costs and complex processes.

[0050] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A BiO 2-x The method for preparing Fe composite nanomaterials is characterized by... The process includes the following steps: Bi(NO3)3·5H2O and PVP are dissolved in anhydrous ethanol, ethylene glycol is added, and the mixture is ultrasonically vibrated for 10 min to ensure homogeneity. The mixture is then transferred to a reaction vessel and reacted at 160℃ for 6 h. After natural cooling to room temperature, the mixture is washed and centrifuged to obtain a Bi2O3 suspension. A 5 mg / mL Bi2O3 suspension is prepared, and a 1 mg / mL FeCl3 solution is added. After stirring for 20 min, a 1 mg / mL NaBH4 solution is added, and stirring continues until a black mixture is formed. The mixture is then centrifuged and dried to obtain BiO2. 2-x @Fe composite nanomaterials, the BiO 2-x The Fe composite nanomaterial comprises internal nanospheres and a surface structure supported on the surface of the internal nanospheres; the internal nanospheres are oxygen-deficient BiO₂. 2-x Nanospheres, wherein 0 < x < 0.5; the surface structure comprises PVP and Fe.

2. The BiO as described in claim 1 2-x The method for preparing Fe composite nanomaterials is characterized by... The molar ratio of Bi(NO3)3·5H2O to PVP is 20:

27.

3. The BiO as described in claim 1 2-x The method for preparing Fe composite nanomaterials is characterized by... During the centrifugation process, the centrifugation speed is 8000-10000 rpm.

4. The BiO as described in claim 1 2-x The method for preparing Fe composite nanomaterials is characterized by... The BiO 2-x The average particle size of the Fe composite nanomaterial is 250–350 nm.

5. The BiO as described in claim 1 2-x The method for preparing Fe composite nanomaterials is characterized by... The molecular weight of the PVP is 5000 to 30000.

6. The BiO as described in any one of claims 1 to 5 2-x Application of Fe composite nanomaterials in environmental photocatalytic antibacterial activity.

7. The application as described in claim 6, characterized in that, The application is a photocatalyst used in any one or more of the following technologies: environmental water treatment, urban sewage treatment, and medical wastewater treatment.

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