Composite nanomaterial, preparation method and application thereof

Abstract

The application relates to the technical field of sewage disinfection, and discloses a composite nanometer material and a preparation method and application thereof. The composite nanometer material comprises copper oxide and zinc oxide in a blending form, the composite nanometer material has a copper oxide / zinc oxide heterostructure inside, and the surface of the composite nanometer material has a nano thorn structure. The application provides a novel composite nanometer material which has high sterilization performance, good environmental compatibility and a low-energy-consumption preparation process, and provides an innovative, efficient and practical technical scheme for solving the challenge of resistant pathogenic bacteria and antibiotic resistance gene transmission in the current sewage deep disinfection field.

Description

Technical Field

[0001] This invention relates to the field of wastewater disinfection technology, and in particular to a composite nanomaterial, its preparation method, and its application. Background Technology

[0002] In the traditional fields of water treatment and wastewater disinfection, technologies such as chlorination, ultraviolet (UV) irradiation, and ozone oxidation have been widely used to inactivate pathogenic microorganisms in water bodies and ensure water quality safety. However, with in-depth research into microbial tolerance and environmental resistance, existing technologies have gradually revealed their limitations. Single disinfection methods (such as chlorination, UV irradiation, or ozone treatment) are often insufficient to completely inactivate resistant pathogenic bacteria present in wastewater, such as *Pseudomonas aeruginosa*. Pseudomonas aeruginosa Bacillus subtilis ( Bacillus subtilis ) and mycobacteria ( Mycobacterium These resistant strains, such as spp., can not only survive the disinfection process but may also become potential hosts for antibiotic resistance genes (ARGs), further spreading their ongoing threat to public health in the urban water cycle.

[0003] In recent years, multimodal synergistic antibacterial strategies have gradually become a key research approach for the efficient inactivation of multidrug-resistant pathogens. These strategies significantly improve inactivation efficiency through multiple mechanisms, such as coupling physical damage and chemical kinetics. In this field, metal-based nanomaterials (e.g., nanosystems containing elements such as copper, zinc, iron, silver, and molybdenum) show promising application prospects. These materials typically rely on the internalization of metal ions within cells and, under external energy excitation such as ultraviolet photocatalysis, generate reactive oxygen species (ROS), such as hydroxyl radicals (·OH) and singlet oxygen (·OH). 1 O2), thereby destroying and inactivating the bacterial structure.

[0004] However, in the complex environment of actual wastewater treatment, the disinfection efficiency of metal-based nanomaterials is often constrained by a variety of factors. Organic pollutants, inorganic ions, and suspended particulate matter in wastewater easily interact with nanomaterials, obscuring their active sites, consuming generated free radicals, or reducing photocatalytic efficiency, leading to a significant decrease in sterilization performance. To achieve ideal disinfection results, it is often necessary to significantly increase the dosage of the material or enhance external energy input (such as enhanced ultraviolet irradiation), which not only increases operating costs but also affects the practicality and sustainability of the technology. Furthermore, some metal nanomaterials (such as silver and molybdenum) may cause the release and accumulation of heavy metal ions under high-dose conditions, posing a potential risk to the aquatic ecosystem and subsequent water reuse processes, thus limiting the feasibility of their large-scale application.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a composite nanomaterial, its preparation method and application, aiming to solve the efficiency bottleneck problem of traditional metal-based nanomaterials in the field of wastewater disinfection.

[0007] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a composite nanomaterial comprising copper oxide and zinc oxide in a blended form, wherein the composite nanomaterial has a copper oxide / zinc oxide heterostructure internally and a nano-spiky structure on its surface.

[0008] Optionally, the surface of the composite nanomaterial carries a positive charge.

[0009] Optionally, in the composite nanomaterial, the molar ratio of copper oxide to zinc oxide is (3-6):1.

[0010] A second aspect of the present invention provides a method for preparing a composite nanomaterial, the method comprising the following steps: The copper source and zinc source are dissolved in the first solvent to obtain the precursor solution; A pH adjuster is added to the precursor solution to adjust the pH of the precursor solution to 8.0-9.0; A second solvent was added to the precursor solution after pH adjustment, and the mixture was subjected to ultrasonic treatment to obtain the composite nanomaterial in the form of a brownish-black powder.

[0011] Optionally, in the precursor solution, the molar concentration ratio of copper source to zinc source is (3-6):1.

[0012] Optionally, the copper source includes one of copper acetate, copper chloride, copper nitrate, and copper sulfate, and the zinc source includes one of zinc acetate, zinc chloride, zinc nitrate, and zinc sulfate.

[0013] Optionally, the first solvent includes one of water, deionized water, and ultrapure water.

[0014] Optionally, the pH adjuster includes either sodium hydroxide or ammonia.

[0015] Optionally, the second solvent includes one of anhydrous ethanol, isopropanol, methanol, and ethylene glycol.

[0016] Optionally, the volume ratio of the second solvent to the pH-adjusted precursor solution is (8.0-9.0):1.

[0017] Optionally, the process parameters of the ultrasonic treatment include: ultrasonic amplitude of 50%, ultrasonic power of 20-30 W, and ultrasonic time of 30-45 min.

[0018] Optionally, after ultrasonic treatment, the process further includes the steps of centrifuging, washing, and drying the product obtained after ultrasonic treatment.

[0019] Optionally, the process parameters for the centrifugation treatment include: a centrifugation speed of 8000-10000 rpm and a centrifugation time of 3-5 min.

[0020] Optionally, the washing process specifically includes the following steps: first washing with water once, and then washing with anhydrous ethanol twice.

[0021] Optionally, the process parameters for the drying process include: a vacuum drying temperature of 60°C and a drying time of 12-24 hours.

[0022] A third aspect of the present invention provides the application of the above-described composite nanomaterials in the field of wastewater disinfection.

[0023] Optionally, the wastewater includes hospital wastewater, industrial wastewater, or surface water.

[0024] The present invention has the following beneficial effects: This invention discloses a composite nanomaterial, its preparation method, and its application. Compared with existing technologies, the composite nanomaterial, its preparation method, and its application provided by this invention have the following significant advantages and beneficial effects: 1. Achieving a highly efficient multi-mode synergistic disinfection mechanism: The composite nanomaterial provided by this invention, through its unique nano-spiky surface structure, can rapidly adsorb and physically puncture bacterial cell membranes; simultaneously, its built-in CuO / ZnO heterojunction interface, under visible light excitation, efficiently separates photogenerated carriers and continuously catalyzes the generation of singlet oxygen (…). 1 O2) and superoxide radicals (•O2) -1. Reactive oxygen species such as Pseudomonas aeruginosa and Bacillus subtilis. This highly efficient synergy between physical damage and chemical oxidation kinetics overcomes the limitations of single disinfection modes, achieving complete inactivation of common resistant pathogenic bacteria in wastewater (such as Pseudomonas aeruginosa and Bacillus subtilis). 2. Breakthrough in efficiency bottleneck of traditional metal-based nanomaterials: Thanks to the above synergistic mechanism, the composite nanomaterial of this invention can achieve excellent sterilization effect at a low dosage, significantly reducing the amount of material added and the potential environmental release risk. At the same time, its unique surface structure endows the material with strong resistance to biofouling, and it can still maintain high disinfection activity in complex wastewater matrices, effectively overcoming the problems of traditional nanomaterials being easily affected by water quality and experiencing efficiency decline. 3. Simple, green and low-energy-consumption preparation process: The preparation method of this invention is based on a room temperature ultrasonic co-precipitation strategy. The operation steps are simple, requiring no high-temperature heat treatment or complex post-treatment, significantly reducing energy input and equipment requirements in the production process, and has good process feasibility and potential for large-scale application. 4. Expanded the application spectrum of photocatalytic disinfection: By constructing a CuO / ZnO heterojunction, the light response range of the material is effectively broadened, enabling it to effectively utilize visible light, reducing dependence on specific ultraviolet light sources, and improving the feasibility and economy of solar energy utilization. 5. Excellent bacterial adsorption and enrichment capabilities: The spiky morphology on the material surface not only provides physical puncture sites but also greatly enhances its adsorption capacity and rate for negatively charged pathogenic bacteria, achieving rapid capture and enrichment of target microorganisms, creating prerequisites for subsequent efficient inactivation.

[0025] In summary, this invention provides a novel composite nanomaterial that combines high-efficiency sterilization performance, good environmental compatibility, and low-energy preparation process. It offers an innovative, efficient, and promising technical solution to address the challenges of the spread of resistant pathogens and antibiotic resistance genes in the current field of deep wastewater disinfection. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the synthesis steps of the composite nanomaterial in Example 1.

[0027] Figure 2 XRD and XPS diagrams of the composite nanomaterials prepared in Example 1: Figure 2 In the diagram, 'a' represents the XRD pattern of the composite nanomaterial. Figure 2 Figure b shows an XPS diagram of oxygen in the composite nanomaterial. Figure 2 In the middle, c is an XPS diagram of zinc in the composite nanomaterial. Figure 2 In the figure, d is an XPS diagram of copper in the composite nanomaterial.

[0028] Figure 3 Surface structure feature diagram of the composite nanomaterial prepared in Example 1: Figure 3 In the middle, 'a' is a low-resolution TEM schematic diagram of the composite nanomaterial. Figure 3 Image b is a high-resolution TEM schematic diagram of the composite nanomaterial. Figure 3 In the middle, c represents the BET specific surface area analysis diagram of the composite nanomaterial. Figure 3 In the diagram, d represents the pore distribution of the composite nanomaterial.

[0029] Figure 4 This is a schematic diagram illustrating the verification of the optimized synthesis conditions for the composite nanomaterials prepared in Examples 1-7: Figure 4 In the figure, 'a' represents the difference in inactivation efficiency when the pH of the precursor solution is changed. Figure 4 In the figure, b represents the difference in inactivation efficiency of the synthesized product when the ultrasonic reaction time (energy consumption) is changed.

[0030] Figure 5 A schematic diagram illustrating the photocatalytic properties of the composite nanomaterial prepared in Example 1: Figure 5 In the diagram, 'a' represents a schematic diagram of the UV-Vis of the composite nanomaterial. Figure 5 Figure b shows a schematic diagram of EPR (Excitation-Reduction) of singlet oxygen excited by composite nanomaterials under visible light catalysis. Figure 5 Figure c shows a schematic diagram of EPR (Excitation-Reduction) of superoxide radicals excited by composite nanomaterials under visible light catalysis. Figure 5 In the diagram, d represents the Baader charge transfer obtained from DFT calculation. Figure 5 In the diagram, e represents the free energy step diagram obtained from the DFT calculation.

[0031] Figure 6 A schematic diagram illustrating the sterilization efficiency of the composite nanomaterial prepared in Example 1: Figure 6 Figure a shows a schematic diagram illustrating the inactivation efficiency of composite nanomaterials at different concentrations against E. coli under dark / light conditions. Figure 6 Figure b shows a schematic diagram illustrating the inactivation efficiency of composite nanomaterials at different concentrations against Bacillus subtilis under dark / light conditions. Figure 6 A schematic diagram illustrating the inactivation efficiency of composite nanomaterials at a concentration of 50 mg / L against Escherichia coli under dark / light conditions in actual wastewater. Figure 6 The diagram in Figure d shows the inactivation efficiency of composite nanomaterials at a concentration of 50 mg / L in actual wastewater against native bacteria under dark / light conditions.

[0032] Figure 7 A schematic diagram illustrating the antifouling properties of the composite nanomaterial prepared in Example 1: Figure 7 In the figure 'a', it indicates that 1-50 mg / L of ammonium ions in R2A medium has almost no effect on the inhibition of Escherichia coli by 50 mg / L of the material. Figure 7 In the figure b, it indicates that 1-50 mg / L of phosphate ions in R2A medium has almost no effect on the inhibition of Escherichia coli by 50 mg / L material. Figure 7 The 'c' indicates that 10-70 mg / L of ammonium ions in R2A medium has almost no effect on the inhibition of Escherichia coli by 50 mg / L of material. Detailed Implementation

[0033] This invention provides a composite nanomaterial, its preparation method, and its application. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0034] This invention provides a composite nanomaterial comprising copper oxide and zinc oxide in a blended form, wherein the composite nanomaterial has a copper oxide / zinc oxide heterostructure inside and a nano-spiky structure on the surface.

[0035] The highly efficient disinfection function of the composite nanomaterials provided in this invention stems from a physicochemical synergistic mechanism determined by their structure: 1. Physical damage mechanism: The surface of the nano-spiky material provides sharp physical action sites. Under the interaction of van der Waals forces and other mechanisms, the densely packed nano-spiky surfaces can effectively pierce or destroy the cell wall / membrane structure of bacteria, causing leakage of contents and achieving physical inactivation. 2. Chemical oxidation kinetics mechanism: The CuO / ZnO heterojunction constructed inside the composite nanomaterial is the core of its photocatalytic activity. Under visible light irradiation, the heterojunction interface can effectively promote photogenerated electrons (electrons). - ) and holes (h + The separation and migration of charge carriers significantly inhibit their recombination. The separated charge carriers react with substances such as water and oxygen on the surface of the composite nanomaterial and in the environment, sustainably and efficiently catalyzing the generation of highly oxidizing reactive oxygen species, mainly including singlet oxygen (…). 1 O2) and superoxide radicals (•O2) - These reactive oxygen species can attack bacterial cellular components (such as lipids, proteins, and DNA), triggering oxidative stress, leading to cellular metabolic disorders and death.

[0036] Based on the above synergistic mechanism, the composite nanomaterials provided in this invention exhibit the following outstanding effects when used for wastewater disinfection: 1. Low-dose, high-efficiency sterilization: The synergistic effect of physical adsorption-puncture and chemical oxidation significantly improves the disinfection efficiency of a single mode. Therefore, even with a low material dosage, highly efficient inactivation of resistant pathogenic bacteria such as Pseudomonas aeruginosa and Bacillus subtilis in wastewater can be achieved, overcoming the limitations of traditional metal-based nanomaterials, which require high dosages and are easily affected by water quality. 2. Excellent antifouling and environmental adaptability: The positively charged nano-spiky surface effectively adsorbs bacteria while exhibiting different interaction characteristics with some organic impurities in wastewater. Furthermore, the active oxygen generated during the photocatalytic process helps decompose some of the attached substances, thus making the material more resistant to fouling in complex water conditions and able to maintain surface activity for a longer period. 3. Broad spectral response and energy saving: The heterogeneous structure endows the material with good visible light response capabilities, reducing dependence on ultraviolet light sources and allowing the use of a wider solar spectrum, resulting in more economical energy utilization.

[0037] In summary, the composite nanomaterial claimed in the embodiments of the present invention, through its unique coupling design of heterojunction interface and nano-spiky surface, successfully integrates a dual sterilization mode of physical damage and chemical oxidation kinetics, becoming a novel disinfection material suitable for complex wastewater environments, with high efficiency, low environmental load and good application prospects.

[0038] In some embodiments, the surface of the composite nanomaterial carries a positive charge.

[0039] The composite nanomaterials have a positively charged surface, while the vast majority of bacteria in wastewater have a negatively charged surface. This electro-attraction, combined with the high specific surface area and adsorption capacity of the composite nanomaterials, enables them to rapidly and massively adsorb and enrich bacteria. This achieves the rapid capture and enrichment of target microorganisms, creating a prerequisite for subsequent efficient inactivation.

[0040] In some embodiments, the molar ratio of copper oxide to zinc oxide in the composite nanomaterial is (3-6):1.

[0041] An optimized molar ratio of copper oxide as the main component and zinc oxide as the auxiliary component is more conducive to the growth of surface spiky structures and optimizes the charge distribution, thus establishing the structural basis for the composite nanomaterial to capture bacteria.

[0042] This invention provides a method for preparing composite nanomaterials, the method comprising the following steps: The copper source and zinc source are dissolved in the first solvent to obtain the precursor solution; A pH adjuster is added to the precursor solution to adjust the pH of the precursor solution to 8.0-9.0; A second solvent was added to the precursor solution after pH adjustment, and the mixture was subjected to ultrasonic treatment to obtain the composite nanomaterial in the form of a brownish-black powder.

[0043] The preparation method provided in this invention, through ingenious step design, achieves the controllable synthesis of CuO / ZnO composite materials with heterojunction and nanospike structures at room temperature. Its core process and underlying mechanism are as follows: S1: Precursor solution preparation: Dissolve the copper and zinc sources in the first solvent and stir thoroughly to form a homogeneous and clear mixed metal ion precursor solution. The selected raw materials are inexpensive, readily available, and environmentally friendly.

[0044] S2: Alkaline coprecipitation and heterogeneous nucleation: A pH adjuster is slowly added dropwise to the precursor solution to precisely adjust and maintain the pH of the system at 8.0-9.0. Under these alkaline conditions, zinc ions (Zn)... 2+ ) and hydroxide ions (OH) - ) combined, because of its solubility product constant (K sp Due to its properties, it precipitates first, forming zinc hydroxide (Zn(OH)₂) crystal nuclei. Subsequently, copper ions (Cu) precipitate first. 2+ Using these initial zinc hydroxide particles as a substrate, secondary nucleation and co-precipitation occur to generate copper hydroxide (Cu(OH)2). This process forms a heterogeneous composite precursor with zinc hydroxide as the core and copper hydroxide growing on the periphery, laying the foundation for the anisotropic growth of the final product.

[0045] In addition, it should be noted that in the preparation method of this invention, the adjustment of the pH value of the precursor solution is a key parameter affecting the morphology, structure, and properties of the final product. Experiments have shown that when the pH value is precisely controlled to approximately 8.0-9.0, the resulting composite nanomaterials exhibit optimal bacterial inactivation performance.

[0046] When the pH of the reaction system is below 8.0 or above 9.0, the sterilization efficiency of the prepared materials decreases significantly. This phenomenon can be reasonably explained by the following nucleation and growth mechanisms: 1. Adverse effects of excessively low pH (e.g., <8.0): Under acidic or weakly alkaline conditions, hydroxide ions (OH-)... - Insufficient concentration of copper ions (Cu) leads to 2+ ) and zinc ions (Zn 2+ The precipitation reaction of copper hydroxide and zinc hydroxide is incomplete. Specifically, the solubility product (K0.05) of copper hydroxide and zinc hydroxide is... sp This determines its lower OH content. -At certain concentrations, effective precipitation is difficult, or only a small amount of amorphous precipitate is formed. This results in a lack of sufficient initial crystal nuclei with well-defined structures in the system, failing to provide a sufficient substrate for subsequent heterogeneous nucleation and anisotropic growth. Ultimately, this leads to poor crystallinity and irregular morphology of the product (such as tending towards spherical or amorphous agglomeration). Its physical puncture resistance and heterojunction interface quality are both unsatisfactory, thus weakening the sterilization effect. 2. Adverse effects of excessively high pH (e.g., >9.0): Under strongly alkaline conditions, OH... - Excessive concentration leads to an excessively rapid precipitation rate of copper and zinc ions. This results in the instantaneous, large-scale, and uniform nucleation and rapid aggregation of copper hydroxide and zinc hydroxide, forming thermodynamically stable spherical or blocky precipitates, rather than the kinetically controlled, slow growth process required by this invention. This rapid precipitation mechanism inhibits the preferential growth of crystals along specific crystal orientations, making it impossible to form a "spiky" morphology with sharp edges and hierarchical structures. Simultaneously, excessively rapid co-precipitation is also detrimental to the ordered and tight interfacial contact and lattice matching between the copper and zinc hydroxide phases, making it difficult to construct high-quality CuO / ZnO heterojunctions.

[0047] S3: Solvent Regulation and Ultrasonic-Induced Crystallization: A second solvent is added to the above reaction system, followed by ultrasonic treatment. This step is crucial for achieving the final morphology and structure of the composite nanomaterials. Its mechanism involves two aspects: 1. The "anti-solvent effect" of the second solvent and directional crystal growth: The addition of the second solvent significantly reduces the polarity of the aqueous system, causing a sharp decrease in the solubility of zinc hydroxide and copper hydroxide (i.e., the "anti-solvent effect"), resulting in a highly supersaturated system. This greatly promotes the rapid and preferential growth of crystals along specific crystal orientations, providing a driving force for the formation of anisotropic structures. 2. The multiple effects of ultrasonic cavitation: Continuous ultrasonic treatment not only ensures the uniform mixing of reactants and solvents, but the resulting cavitation effect, through local extreme high temperature, high pressure, and strong fluid shear force, plays the following core roles: ① Breakup and Reassembly: Breaking up the initially formed micron-sized aggregates creates conditions for reassembly at the nanoscale. ② Directional Adhesion and Dendrite Growth: Cavitation microjets and shock waves drive the orderly directional adhesion of nanoparticles, combined with the aforementioned rapid crystal growth, ultimately inducing the formation of a multi-level, multi-directional array of nanospikes on the surface. ③ Heterojunction Interface Construction: The high-energy microenvironment generated by the cavitation effect promotes close contact and lattice matching between the copper hydroxide and zinc hydroxide phases. During the ultrasonic process and subsequent slight oxidation (partial dehydration and oxidation of hydroxides at room temperature), a stable and continuous CuO / ZnO pn heterojunction interface is constructed in situ.

[0048] After the reaction was complete, the solid product in the system was a brownish-black powder, indicating that copper oxide / zinc oxide composite nanomaterials had been formed. The final product could be obtained by simple centrifugation, washing, and drying.

[0049] Through the above preparation method, this invention achieves the following beneficial technical effects: 1. One-step in-situ construction of complex structures: This method, under single reaction vessel and room temperature conditions, simultaneously achieves the in-situ construction of the surface morphology of nanospikes and the interface structure of heterojunctions through the coupling of co-precipitation-solvent regulation-ultrasonic treatment. The process is extremely simple, requiring no high-temperature calcination, template agents, or complex post-processing steps. 2. Controllable morphology and structure: By precisely controlling the pH value, the addition of the second solvent, and the ultrasonic parameters (power, time), the density and size of the nanospikes and the interface quality of the heterojunctions can be effectively controlled, thereby optimizing the final performance of the material. 3. Energy-saving and efficient, suitable for scale-up: The entire preparation process is carried out at room temperature and pressure, with extremely low energy input. The reagents used are conventional, the equipment requirements are simple, and it has good process stability and potential for large-scale production.

[0050] In summary, the preparation method claimed in the embodiments of the present invention is an efficient, energy-saving, and controllable synthetic route that can stably prepare CuO / ZnO composite nanomaterials with unique physical structures (nanospins) and electronic structures (heterojunctions), providing a reliable material basis and production guarantee for their application in fields such as wastewater disinfection.

[0051] In some embodiments, the molar concentration ratio of copper source to zinc source in the precursor solution is (3-6):1.

[0052] In some embodiments, the copper source includes one of copper acetate, copper chloride, copper nitrate, and copper sulfate, and the zinc source includes one of zinc acetate, zinc chloride, zinc nitrate, and zinc sulfate.

[0053] In some embodiments, the first solvent includes one of water, deionized water, and ultrapure water.

[0054] In some embodiments, the pH adjuster includes either sodium hydroxide or ammonia.

[0055] In some embodiments, the second solvent includes one of anhydrous ethanol, isopropanol, methanol, and ethylene glycol.

[0056] In some embodiments, the volume ratio of the second solvent to the pH-adjusted precursor solution is (8.0-9.0):1.

[0057] In some embodiments, the process parameters of the ultrasonic treatment include: ultrasonic amplitude of 50%, ultrasonic power of 20-30 W, and ultrasonic time of 30-45 min.

[0058] In one specific embodiment of the present invention, in order to achieve controllable growth of specific morphologies and structures of composite nanomaterials, the process parameters of the ultrasonic treatment step were optimized.

[0059] The ultrasonic treatment is preferably performed in an ultrasonic cell disruptor, which can provide highly focused mechanical energy to create a local microenvironment of instantaneous high temperature, high pressure, and high shear force in the reaction system through intense cavitation effects (including rapid bubble formation, growth, and violent collapse). The specific process parameters are set as follows: ultrasonic amplitude of 50%, ultrasonic power of 20W to 30W, and ultrasonic time of 30-45 min.

[0060] The above parameter ranges are set based on systematic experimental results of material growth kinetics and final performance. Specifically: 1. Power and amplitude settings: A 50% amplitude and 20-30W power provide moderate energy input. This energy level is sufficient to drive uniform mixing of the reaction system and generate sufficient cavitation energy to achieve: ① Crystal growth drive: Promotes the directional adhesion and preferential growth of zinc hydroxide and copper hydroxide crystals, thereby guiding the formation of multi-level nanospike structures. ② Structure stabilization: Promotes close contact and lattice matching between CuO and ZnO phases at the interface, which is beneficial to the formation of stable pn heterojunctions. ③ Prevention of excessive fragmentation: At the same time, avoids excessive physical damage to the initially formed nanostructures caused by excessive energy. 2. Determination of processing time: A 30-minute ultrasonic time is a key technical optimization point. This duration is the window period for achieving the best balance between material morphological integrity and final sterilization performance. The technical principle is: ① Staged growth: Within a timescale of approximately 30 minutes, the crystal undergoes a sufficient nucleation-directional growth-structure stabilization process, which is sufficient to form a nanospike array with a rich surface and robust structure. ② Balance between performance and morphology: Experiments have shown that if the ultrasonic time is too short (e.g., <30 minutes), the reaction is insufficient, the heterojunction interface is not fully constructed, and the growth of nanospikes is inadequate, resulting in the material's physical adsorption and photocatalytic activity not reaching their optimal levels. Conversely, if the ultrasonic time is too long (e.g., >45 minutes), the continuous high-energy cavitation effect will have an "over-processing" effect on the already formed fine nanospike structure, leading to blunting of the spike tips, structural damage, or even aggregation, which in turn destroys its physical puncture ability and effective specific surface area, thus resulting in a decrease in the inactivation rate.

[0061] Therefore, the ultrasonic processing parameter combination of 50% ultrasonic amplitude, 20-30 W ultrasonic power, and 30-45 min ultrasonic time determined in this embodiment is not a conventional choice in the art, but rather a golden process window determined after creative experimental optimization. Under these parameters, the "anti-solvent effect" and "cavitation effect" can be most effectively synergistically combined, maximizing the physical-chemical synergistic inactivation efficiency of the material against pathogenic bacteria while ensuring the formation of an ideal spiny heterostructure.

[0062] In some preferred embodiments, the process parameters of the ultrasonic treatment include: ultrasonic amplitude of 50%, ultrasonic power of 25 W, and ultrasonic time of 30 min.

[0063] In some embodiments, after ultrasonic treatment, the steps further include: centrifuging, washing and drying the product obtained after ultrasonic treatment in sequence.

[0064] In some embodiments, the process parameters for the centrifugation treatment include: a centrifugation speed of 8000-10000 rpm and a centrifugation time of 3-5 min.

[0065] In some embodiments, the washing process specifically includes the following steps: washing once with water and then washing twice with anhydrous ethanol.

[0066] Water washing removes loosely adsorbed sodium ions (when the pH adjuster is sodium hydroxide), unreacted metal salts, hydroxide ions, etc., preventing the subsequent formation of alkaline impurities. It also avoids excessive washing, which could lead to rehydration of the material surface and dulling of the spiky structure. Anhydrous ethanol washing rapidly replaces the hydration layer on the precursor surface, preventing collapse / adhesion during drying. Finally, gentle dehydration stabilizes and solidifies the crystal structure.

[0067] In some embodiments, the process parameters for the drying process include: a drying temperature of 60°C and a drying time of 12-24 h.

[0068] This invention provides the application of the above-mentioned composite nanomaterials in the field of wastewater disinfection.

[0069] The composite nanomaterials provided in this invention can rapidly destroy the bacterial cell membrane structure through an adsorption-puncture process under dark conditions. This physical inactivation mechanism has strong anti-interference capabilities, resisting interference from common inorganic ions and organic nutrients in wastewater, and selectively inactivating bacteria. Under visible light irradiation, singlet oxygen and superoxide radicals are further generated through CuO / ZnO heterojunction catalysis, which efficiently and thoroughly inactivate resistant bacteria by destroying their cell membranes, proteins, and DNA at multiple targets.

[0070] In some embodiments, the wastewater includes hospital wastewater, industrial wastewater, or surface water.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0072] The following detailed description uses specific examples.

[0073] Example 1 The preparation process of a composite nanomaterial is shown in the flowchart below. Figure 1This includes the following steps: S1: Dissolve anhydrous copper acetate and anhydrous zinc acetate in deionized water to obtain a homogeneous precursor solution with a molar ratio of 3:1. S2: Slowly add sodium hydroxide solution dropwise to the precursor solution to adjust the pH to 8.0; S3: Add anhydrous ethanol for continuous ultrasonic treatment. The volume ratio of anhydrous ethanol to the precursor solution is 9:1. The ultrasonic treatment process parameters include: ultrasonic amplitude of 50%, ultrasonic power of 25W, and ultrasonic time of 30 min. S4: Centrifugation, washing, and drying yield fine brownish-black powder, which is the composite nanomaterial. The centrifugation speed is 9000 rpm for 5 min, followed by washing with water once and anhydrous ethanol twice, and finally vacuum drying at 60℃ for 12 hours.

[0074] Example 2 The preparation of a composite nanomaterial is basically the same as that in Example 1, except that in step S2, sodium hydroxide solution is slowly added dropwise to the precursor solution to adjust the pH to 7.

[0075] Example 3 The preparation of a composite nanomaterial is basically the same as that in Example 1, except that in step S2, sodium hydroxide solution is slowly added dropwise to the precursor solution to adjust the pH to 9.

[0076] Example 4 The preparation of a composite nanomaterial is basically the same as that in Example 1, except that in step S2, sodium hydroxide solution is slowly added dropwise to the precursor solution to adjust the pH to 10.

[0077] Example 5 The preparation of a composite nanomaterial is basically the same as that in Example 1, except that in step S2, sodium hydroxide solution is slowly added dropwise to the precursor solution to adjust the pH to 11.

[0078] Example 6 The preparation of a composite nanomaterial is basically the same as that in Example 1, except that the ultrasonic time in step S3 is 45 min.

[0079] Example 7 The preparation of a composite nanomaterial is basically the same as that in Example 1, except that the ultrasonic time in step S3 is 60 min.

[0080] Performance testing Figure 2XRD and XPS diagrams of the composite nanomaterials prepared in Example 1: Figure 2 In the diagram, 'a' represents the XRD pattern of the composite nanomaterial. Figure 2 Figure b shows an XPS diagram of oxygen in the composite nanomaterial. Figure 2 In the middle, c is an XPS diagram of zinc in the composite nanomaterial. Figure 2 In the figure, d is an XPS diagram of copper in the composite nanomaterial.

[0081] Figure 3 Surface structure feature diagram of the composite nanomaterial prepared in Example 1: where Figure 3 In the middle, 'a' is a low-resolution TEM schematic diagram of the composite nanomaterial. Figure 3 Image b is a high-resolution TEM schematic diagram of the composite nanomaterial. Figure 3 In the middle, c represents the BET specific surface area analysis diagram of the composite nanomaterial. Figure 3 In the diagram, d represents the pore distribution of the composite nanomaterial. From... Figure 3 As can be seen from the above, the composite nanomaterial prepared in Example 1 has a nano-spiky surface and a copper oxide / zinc oxide heterostructure.

[0082] Figure 4 This is a schematic diagram illustrating the verification of the optimized synthesis conditions for the composite nanomaterials prepared in Examples 1-7: where... Figure 4 In the figure, 'a' represents the difference in inactivation efficiency when the pH of the precursor solution is changed. Figure 4 In Figure b, the difference in inactivation efficiency during synthesis is achieved by varying the ultrasonic reaction time (energy consumption). From... Figure 4 As can be seen, the sterilization effect is best when the final pH is close to 8.0. The experiment found that lower or higher pH is not conducive to the sterilization of spiky nanomaterials. 30 minutes has been experimentally proven to be the optimal time point for balancing morphology and inactivation rate.

[0083] Figure 5 A schematic diagram illustrating the photocatalytic properties of the composite nanomaterial prepared in Example 1: Figure 5 In the diagram, 'a' represents a schematic diagram of the UV-Vis of the composite nanomaterial. Figure 5 Figure b shows a schematic diagram of EPR (Excitation-Reduction) of singlet oxygen excited by composite nanomaterials under visible light catalysis. Figure 5 Figure c shows a schematic diagram of EPR (Excitation-Reduction) of superoxide radicals excited by composite nanomaterials under visible light catalysis. Figure 5 In the diagram, d represents the Baader charge transfer obtained from DFT calculation. Figure 5 In the diagram, e represents the free energy step diagram obtained from the DFT calculation.

[0084] The inactivation efficacy of the composite nanomaterials prepared in Example 1 in ultrapure water, R2A culture medium, and actual wastewater was tested. Step 1: Incubate Escherichia coli and Bacillus subtilis overnight in liquid culture medium until the logarithmic phase.

[0085] Step 2: Disperse CuO / ZnO of different masses evenly into different matrices using an ultrasonic homogenizer, and add bacteria to adjust the concentration to 10. 7 CFU / mL.

[0086] Step 3: Perform sterilization tests with / without applying visible light.

[0087] like Figures 6-7 The diagram shows a performance evaluation of composite nanomaterials in inactivating *Escherichia coli* and *Bacillus subtilis*. From... Figure 6 It can be observed that under dark conditions, composite nanomaterials can rapidly inactivate more than 3 log bacteria within 1 minute by virtue of their physical damage mechanism, which is an advantage in inactivation rate compared with previously reported metal-based nanomaterials. Under light irradiation, the composite nanomaterials further enhance the inactivation rate through their physical damage-chemical oxidation synergistic mechanism, completely inactivating 7 log bacteria within 3 min at a relatively low dose (10 mg / L), far exceeding the sterilization effect of similar catalysts (Defect-richgraphene stabilized atomically dispersed Cu3 clusters with enhanced oxidase-like activity for antibacterial applications (dose 100 mg / L, average inactivation rate 0.4 log / min); Catalytic disinfection: Quasi-dynamically monitoring bacteriasterilization based on CuNPs / ZnIn2S4 disinfectants and in-situ CuNPs regeneration (dose 100 mg / L, average inactivation rate 0.066-0.1 log / min); Zinc–SilverNitroprusside Nanocomposites: Synthesis, Characterization, and Antibacterial Properties with Cytocompatibility (dose 500 mg / L, average inactivation rate 0.00625 log / min)). Figure 7In the range of 1-50 mg / L, inorganic ammonium ions and phosphate and sulfate ions in the range of 10-70 mg / L had almost no significant inhibitory effect on the antibacterial effect of the composite nanomaterials. At the same time, the rapid inactivation effect of the composite nanomaterials in wastewater was hardly affected (more than 3 log bacteria were inactivated within 1 min).

[0088] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A composite nanomaterial, characterized in that, The composite nanomaterial comprises copper oxide and zinc oxide in a blended form, and the composite nanomaterial has a copper oxide / zinc oxide heterostructure inside and a nano-spiky structure on the surface.

2. The composite nanomaterial according to claim 1, characterized in that, The surface of the composite nanomaterial carries a positive charge.

3. The composite nanomaterial according to claim 1, characterized in that, In the composite nanomaterial, the molar ratio of copper oxide to zinc oxide is (3-6):

1.

4. A method for preparing the composite nanomaterial according to any one of claims 1-3, characterized in that, The preparation method includes the following steps: The copper source and zinc source are dissolved in the first solvent to obtain the precursor solution; A pH adjuster is added to the precursor solution to adjust the pH of the precursor solution to 8.0-9.0; A second solvent was added to the precursor solution after pH adjustment, and the mixture was subjected to ultrasonic treatment to obtain the composite nanomaterial in the form of a brownish-black powder.

5. The method for preparing composite nanomaterials according to claim 4, characterized in that, In the precursor solution, the molar concentration ratio of copper source to zinc source is (3-6):1; The copper source includes one of copper acetate and copper chloride, and the zinc source includes one of copper acetate and zinc chloride.

6. The method for preparing composite nanomaterials according to claim 4, characterized in that, The first solvent includes one of water, deionized water, and ultrapure water; The pH adjuster includes either sodium hydroxide or ammonia.

7. The method for preparing composite nanomaterials according to claim 4, characterized in that, The second solvent includes one of anhydrous ethanol, isopropanol, methanol, and ethylene glycol; The volume ratio of the second solvent to the pH-adjusted precursor solution is (8.0-9.0):

1.

8. The method for preparing composite nanomaterials according to claim 4, characterized in that, The process parameters for the ultrasonic treatment include: ultrasonic amplitude of 50%, ultrasonic power of 20-30 W, and ultrasonic time of 30-45 min.

9. The method for preparing composite nanomaterials according to claim 4, characterized in that, After ultrasonic treatment, the process also includes the following steps: centrifugation, washing, and drying of the product obtained after ultrasonic treatment.

10. The application of the composite nanomaterial described in claims 1-3 in the field of wastewater disinfection.

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