Deodorizing particles based on core-shell structure and preparation method and application thereof

Abstract

The application relates to the technical field of daily chemical products, and discloses deodorizing particles based on a core-shell structure and a preparation method and application thereof, wherein the deodorizing particles sequentially comprise, from inside to outside, a core layer composed of porous zinc oxide microspheres, an inner isolation layer coated on the surface of the core layer, a functional shell layer coated on the surface of the inner isolation layer, wherein the functional shell layer contains submicron particle-coated biological enzymes, natural plant source deodorizing and bacteriostatic agents and microcapsule fragrances, and an outer isolation layer coated on the surface of the functional shell layer. Through the ingenious four-layer structure design, the inner isolation layer effectively solves the problems of incompatibility between zinc oxide and enzymes, adsorption of fragrances and the like; the outer isolation layer realizes slow release of the fragrances; the functional shell layer and the core layer cooperatively provide multiple deodorizing mechanisms of physical adsorption, chemical neutralization, enzyme catalytic decomposition, organic chemical reaction and bacteriostasis; the deodorizing particles can realize broad-spectrum, high-efficiency and long-lasting hierarchical deodorization, and have the functions of bacteriostasis and long-acting fragrance.

Description

Technical Field

[0001] This invention relates to the field of daily chemical products technology, and in particular to a deodorizing granule based on a core-shell structure, its preparation method, and its application. Background Technology

[0002] With the improvement of living standards, people have placed higher demands on the odor comfort of their living environment and consumer products. The unpleasant odors generated in daily life, such as body odor, foot odor, pet odor, and the smell of rotting kitchen waste, have complex and diverse chemical compositions. According to the standard GB / T 33610.1-2019 "Determination of Deodorizing Performance of Textiles Part 1: General Rules", the main odor chemical components include ammonia (alkaline), acetic acid and isovaleric acid (acidic), hydrogen sulfide and methanethiol (sulfur-containing), 2-nonenal (long-chain unsaturated aldehyde), and indole (nitrogen-containing heterocyclic compounds). These odor-causing substances have vastly different chemical properties, and a single deodorization mechanism, such as simple physical adsorption, acid-base neutralization, or enzyme-catalyzed decomposition, is often insufficient to achieve broad-spectrum, rapid, and long-lasting efficient removal.

[0003] In existing technologies, combining porous zinc oxide (which possesses excellent acid-base neutralization and physical adsorption capabilities) with bio-enzymes (which have specific catalytic decomposition capabilities) is a common approach to improve the broad-spectrum deodorization effect. However, when porous zinc oxide and bio-enzymes coexist in the same system, the metal ions (Zn) on the zinc oxide surface... 2+ The slow dissolution of enzymes can lead to irreversible denaturation and inactivation of enzyme proteins, severely shortening the product's shelf life and preventing the two from coexisting stably and working synergistically in the same system. Meanwhile, in traditional deodorization technologies, fragrance molecules are easily captured by porous adsorbents (such as porous zinc oxide) and lose their volatility, resulting in a poor fragrance experience; furthermore, the functional components compete and interfere with each other in a simple mixed system, lacking the ability to systematically treat multiple odors.

[0004] Therefore, developing a hierarchical deodorizing material that can achieve stable coexistence of multiple components, orderly synergy of functions, and broad-spectrum high efficiency is a technical problem that urgently needs to be solved in the current field of daily chemical deodorization. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a deodorizing particle based on a core-shell structure, its preparation method, and its application, aiming to solve the problem of Zn in the coexistence of porous zinc oxide and biological enzymes in the prior art. 2+ Technical problems include enzyme inactivation due to dissolution, loss of volatility due to the capture of fragrance molecules by porous adsorbents, and disordered competition and mutual interference among various functional components.

[0006] The technical solution of the present invention is as follows: A core-shell structure-based deodorizing granule, wherein the deodorizing granule comprises, from the inside out: The core layer is composed of porous zinc oxide microspheres; An inner isolation layer covers the surface of the core layer; A functional shell layer is formed on the surface of the inner isolation layer. The functional shell layer contains submicron-sized particles encapsulating biological enzymes, natural plant-derived deodorizing and antibacterial agents, and microcapsule fragrances. An outer isolation layer is applied to the surface of the functional shell layer.

[0007] The deodorizing granules based on a core-shell structure, wherein the core layer accounts for 20-50% of the total mass of the deodorizing granules, the inner isolation layer accounts for 2-8% of the total mass of the deodorizing granules, the functional shell layer accounts for 30-60% of the total mass of the deodorizing granules, and the outer isolation layer accounts for 1-3% of the total mass of the deodorizing granules.

[0008] The deodorizing particles based on a core-shell structure, wherein the porous zinc oxide microspheres have a diameter of 0.5-8 μm and a BET specific surface area of ​​40-100 m². 2 / g, with a pore size distribution of 2-15nm mesopores and 30-100nm macropores in a bimodal pattern.

[0009] The deodorizing particles based on a core-shell structure, wherein the inner isolation layer is selected from at least one of cyclodextrin-based materials and modified starch materials.

[0010] The deodorizing particles based on a core-shell structure, wherein the outer insulating layer is composed of porous silica.

[0011] The deodorizing particles based on a core-shell structure, wherein the submicron-sized particles are coated with urease and / or lipase; and the submicron-sized particles coated with the bioenzymes use modified cellulose as the wall material.

[0012] The deodorizing particles based on a core-shell structure, wherein the natural plant-derived deodorizing and antibacterial agent is selected from at least one of phenolic plant-derived components, terpenoid plant-derived components, and alkaloid plant-derived components.

[0013] The deodorizing particles based on a core-shell structure, wherein the natural plant-derived deodorizing and antibacterial agent is selected from one or more of the following: persimmon tannin, tea tree oil, sophora flavescens extract, coptis chinensis extract, eugenol, thymol, cinnamaldehyde, citral, carvacrol, 1,8-cineole, menthol, rosemary extract, grapefruit peel extract, honeysuckle extract, scutellaria baicalensis extract, and artemisia argyi oil.

[0014] A method for preparing deodorizing particles based on a core-shell structure as described in this invention, comprising the steps of: Porous zinc oxide microspheres were prepared in advance by a hydrothermal-calcination method, and the porous zinc oxide microspheres served as the core layer. The porous zinc oxide microspheres are dispersed in an inner isolation layer material solution and dried to form an inner isolation layer on the surface of the porous zinc oxide microspheres. The functional shell material is mixed and coated onto the surface of the inner isolation layer, and then dried to form the functional shell. The deodorizing particles based on the core-shell structure are obtained by coating the surface of the functional shell layer with an outer isolation layer and drying it.

[0015] An application of core-shell structure-based deodorizing particles as described in this invention, wherein the deodorizing particles are used to prepare air fresheners, fabric deodorizers, shoe and sock deodorizers, pet deodorizers, laundry detergent deodorizers, or refrigerator deodorizers.

[0016] Beneficial effects: This invention constructs a physical barrier between the core-layer porous zinc oxide microspheres and the functional shell layer by setting an inner isolation layer, effectively blocking Zn. 2+ The fragrance diffuses into the functional shell, thus protecting the activity of the enzymes within it and preventing denaturation and inactivation due to metal ion dissolution. Simultaneously, the inner isolation layer prevents fragrance molecules from diffusing into the porous core structure and being permanently adsorbed, preserving the fragrance's volatility. The outer isolation layer acts as a diffusion barrier, controlling the rate of fragrance release and achieving long-lasting sustained release. The functional shell encapsulates submicron-sized particles containing enzymes, natural plant-derived deodorizing and antibacterial agents, and microencapsulated fragrance compounds. The combination of the outer layer and the porous zinc oxide core layer forms a hierarchical deodorization system that progresses from the outside in: the outer isolation layer enriches odor molecules through pore size sieving; the functional shell layer removes odor-producing microorganisms at the source through enzymatic decomposition, multiple chemical reactions of plant-derived deodorizing and antibacterial agents (such as neutralization of phenolic hydroxyl groups, hydrogen bonding, inclusion, etc.), and antibacterial effects; and the core layer thoroughly removes residual small-molecule acidic and alkaline gases through physical adsorption of porous zinc oxide and acid-base neutralization / Lewis acid coordination complexation. The three mechanisms complement each other and synergistically enhance each other, achieving highly efficient and broad-spectrum removal of various odors. Furthermore, the submicron-sized particles encapsulating the bio-enzyme have a high specific surface area, allowing for efficient contact with gaseous odor-generating substances even in a dry state, improving deodorization efficiency under dry conditions. Therefore, this invention effectively achieves a comprehensive effect of stable enzyme activity maintenance, long-lasting sustained release of fragrance, and synergistic and orderly deodorization by multiple components. Attached Figure Description

[0017] Figure 1 The present invention provides a flowchart of a method for preparing deodorizing particles based on a core-shell structure.

[0018] Figure 2 The image shows the porous zinc oxide microspheres prepared in Example 1 of this invention at a scale of 30 μm.

[0019] Figure 3The image shows the porous zinc oxide microspheres prepared in Example 1 of this invention at a scale of 10 μm.

[0020] Figure 4 This is an electron microscope image of the porous zinc oxide microspheres prepared in Example 1 of this invention at the 8 μm scale.

[0021] Figure 5 The image shows the porous zinc oxide microspheres prepared in Example 1 of this invention at a scale of 5 μm. Detailed Implementation

[0022] This invention provides deodorizing particles based on a core-shell structure, their preparation method, and applications. 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 merely illustrative and not intended to limit the invention.

[0023] This invention provides a core-shell structure-based deodorizing particle, wherein the deodorizing particle comprises, from the inside out: a core layer composed of porous zinc oxide microspheres; an inner isolation layer covering the surface of the core layer; a functional shell layer covering the surface of the inner isolation layer, the functional shell layer containing submicron-sized particles encapsulating bio-enzymes, natural plant-derived deodorizing and antibacterial agents, and microcapsule fragrances; and an outer isolation layer covering the surface of the functional shell layer. The submicron-sized particles encapsulating bio-enzymes refer to particles formed by loading bio-enzymes into submicron-scale carrier particles or encapsulating them with polymer wall materials through physical or chemical means; the natural plant-derived deodorizing and antibacterial agents refer to components derived from plants that possess both odor-eliminating and microbial growth-inhibiting functions; and the microcapsule fragrances refer to tiny capsules formed by embedding fragrances using wall materials.

[0024] The deodorizing particles based on a core-shell structure provided by this invention treat odor molecules in an orderly process from the outside in, progressively advancing to the inside, thereby achieving synergistic effects of multiple deodorizing mechanisms: First stage (outer isolation layer): Odor gas molecules first come into contact with the porous SiO2 outer isolation layer. This layer allows small molecule gases (NH3, H2S, etc.) to pass through preferentially through the pore size sieving effect, while large molecule organic matter is initially intercepted and enriched. Second level (functional shell): Odor molecules entering the shell face the synergistic effect of multiple deodorization mechanisms: a) Enzymatic decomposition: In spray application scenarios, the submicron-sized particles coated with enzymes swell upon contact with water, urease catalyzes the hydrolysis of urea, and lipase catalyzes the hydrolysis of short-chain fatty acid esters, specifically decomposing organic odor-causing substances into odorless small molecules; b) Multiple effects of plant-derived deodorizing and antibacterial agents: When persimmon tannin is used, its abundant phenolic hydroxyl groups capture alkaline gases such as ammonia through neutralization reactions, capture neutral molecules such as hydrogen sulfide through hydrogen bonding, and fix organic amines and thiols through inclusion, achieving comprehensive organic chemical reaction removal of different types of odor-causing molecules; at the same time, persimmon tannin and / or other plant-derived antibacterial ingredients kill odor-producing microorganisms (such as Staphylococcus aureus and Escherichia coli), blocking the path of microbial decomposition of organic matter to produce odor from the source; c) Fragrance release: Microcapsule fragrance continuously releases a pleasant fragrance, providing a refreshing sensory experience; The third stage (core layer): After multiple treatments in the shell layer, residual small-molecule acidic and alkaline gases (NH3, H2S, acetic acid, etc.) eventually diffuse to the core layer and are completely removed by porous zinc oxide through the following mechanisms: 1) Physical adsorption: High specific surface area (40-100m²) 2 / g) and hierarchical porous structure provide abundant adsorption sites; 2) acid-base neutralization reaction: H2S+ZnO→ZnS+H2O; 3) Lewis acid coordination complexation: NH3 with coordinated unsaturated Zn 2+ Coordination.

[0025] In the aforementioned multi-tiered treatment process, the physical / inorganic chemical adsorption of the core layer, the organic chemical reaction (persimmon tannin) in the functional shell layer, and the bio-enzyme catalytic decomposition form a complementary and synergistic deodorization network. Specifically, porous zinc oxide enriches odor molecules through physical adsorption, forming high-concentration micro-regions within the particles; persimmon tannin is locked and transformed within these micro-regions through chemical reactions; and bio-enzymes specifically decompose particular organic substrates. These three mechanisms function independently and do not conflict with each other, collectively achieving a broad-spectrum and highly efficient deodorization effect far exceeding that of any single deodorization technology.

[0026] Although the inner barrier layer does not directly participate in the deodorization reaction, its physical isolation function is crucial for the long-term stable operation of the entire system. It ensures that the core layer (ZnO) and the functional shell layer (enzymes, persimmon tannins, etc.), two functionally complementary but chemically incompatible components, can coexist in the same particle. Its physical barrier function is key to the stable operation of the entire system, effectively preventing the dissolution of Zn from the core layer ZnO. 2+ Diffusion into the functional shell protects the activity of biological enzymes and also prevents fragrance molecules from diffusing into the core pores and being permanently adsorbed, thus ensuring the stability of each functional component in long-term coexistence.

[0027] In some embodiments, the porous zinc oxide microspheres have a diameter of 0.5-8 μm, a BET specific surface area of ​​40-100 m² / g, and a bimodal pore size distribution of 2-15 nm mesopores and 30-100 nm macropores.

[0028] In this embodiment, porous zinc oxide microspheres with high specific surface area and bimodal pore distribution provide abundant adsorption sites and rapid diffusion channels for odor molecules. Mesopores exhibit strong adsorption capacity for small and medium-sized molecules (such as NH3 and H2S), while macropores help reduce mass transfer resistance and improve the overall diffusion rate of gas molecules. In a specific example, porous zinc oxide microspheres prepared by a hydrothermal-calcination method achieved a BET specific surface area of ​​68 m² / g and exhibited typical mesoporous and macroporous structures. Compared to ordinary zinc oxide (specific surface area of ​​only about 5 m² / g), this structure increased the 2-hour dark-state removal rates of ammonia and hydrogen sulfide from 85% and 84% to 95% and 96%, respectively. Through this design, this embodiment effectively achieves efficient adsorption and conversion of residual small-molecule acidic and alkaline odor gases in the core layer, providing a strong guarantee for the core deodorization effect.

[0029] In some embodiments, the core layer accounts for 20%-50% of the total particle mass, the inner isolation layer accounts for 2%-8% of the total particle mass, the functional shell layer accounts for 30%-60% of the total particle mass, and the outer isolation layer accounts for 1%-3% of the total particle mass. This specific mass distribution ensures that the integrity of each functional layer and their synergistic effect are not unbalanced due to any one layer being too thick or too thin. Further optimization of the mass proportions is necessary to achieve better particle stability and deodorization performance while maintaining the functional integrity of each layer. Preferably, the core layer accounts for 30%-45% of the total particle mass, the inner isolation layer accounts for 3%-6% of the total particle mass, the functional shell layer accounts for 40%-55% of the total particle mass, and the outer isolation layer accounts for 1.5%-2.5% of the total particle mass. This optimized range ensures that the core layer has sufficient mass to provide adequate adsorption capacity (30%-45%), the inner isolation layer (3%-6%) and the outer isolation layer (1.5%-2.5%) form a continuous and effective barrier membrane, and the functional shell layer (40%-55%) can load sufficient active ingredients. Taking a particle with a target particle size D50 of 12.5 μm as an example, if its core layer mass is 38%, the inner isolation layer is 5%, the functional shell layer is 55%, and the outer isolation layer is 2%, the layers can achieve a good physical match, avoiding easy detachment due to excessive shell thickness or excessively rapid particle settling due to excessive core layer density. Through this optimization scheme, the resulting particles not only show improved deodorization performance (such as the combined removal rate of ammonia and acetic acid) over a wider range of conditions, but also exhibit a more stable enzyme activity retention rate in accelerated aging tests.

[0030] In some embodiments, the inner isolation layer is selected from at least one of cyclodextrin-based materials and modified starch materials, but is not limited thereto.

[0031] In this embodiment, cyclodextrin has a hollow cylindrical molecular cavity, and modified starch (such as sodium octenyl succinate starch) has good film-forming properties and hydrophobicity. Both can form a dense barrier layer on the core layer surface through physical coating. The main function of this structure is to block the dissolution of Zn from the zinc oxide in the core layer. 2+ The design allows for diffusion into the functional shell; secondly, it prevents fragrance molecules in the functional shell from diffusing into the porous structure of the core layer and being permanently adsorbed, thus losing volatility; and finally, it provides hydrophilic microdomains similar to the natural environment for the bioenzymes in the functional shell. Assuming the inner isolation layer material is sodium octenyl succinate starch, its coating thickness on the surface of the porous zinc oxide microspheres is approximately 50-300 nm, which is sufficient to effectively slow down ion migration. Accelerated aging experiments verified that the lipase activity retention rate in particles containing this inner isolation layer reached 86%, while the retention rate of the control sample without the inner isolation layer was only 51%. Through the above design, this embodiment effectively ensures the long-term activity of the bioenzymes in the functional shell, solving the core problem of the inability of ZnO and enzymes to coexist stably. For example, the cyclodextrin material is selected from at least one of β-cyclodextrin and hydroxypropyl-β-cyclodextrin, and the modified starch material is sodium octenyl succinate starch, but is not limited to these.

[0032] In some embodiments, the submicron-sized particles coated with bioenzymes are urease and / or lipase; and the submicron-sized particles coated with bioenzymes use modified cellulose as the wall material. In this embodiment, the urease can specifically catalyze the hydrolysis of urea to produce ammonia and carbon dioxide, thereby decomposing urea-related odor-producing substances at the source; the lipase can decompose oily pollutants and short-chain fatty acid esters (such as isovalerates) in odor sources; the modified cellulose, such as hydroxypropyl methylcellulose (HPMC) or ethyl cellulose, is suitable as a wall material for nano-spray drying due to its good film-forming properties, biocompatibility, and protection of enzyme proteins. For example, using HPMC as the wall material to coat a mixture of urease and lipase, the submicron-sized particles prepared by nano-spray drying can achieve an enzyme activity retention rate of 90% (urease) and 87% (lipase). The wall material not only protects the activity of the enzymes during drying and coating processes, but also rapidly swells upon contact with water, releasing enzyme molecules and ensuring rapid functioning in humid environments.

[0033] In some embodiments, the natural plant-derived deodorizing and antibacterial agent is selected from at least one of phenolic plant-derived components, terpenoid plant-derived components, and alkaloid plant-derived components, but is not limited thereto. Phenolic plant-derived components (such as persimmon tannin) mainly rely on abundant phenolic hydroxyl groups to achieve chemical reactions such as neutralization, hydrogen bonding, and inclusion; terpenoid plant-derived components (such as tea tree oil and citral) have strong antibacterial and reactive activities due to the double bonds and functional groups in their molecular structure; alkaloid plant-derived components (such as matrine in Sophora flavescens extract) can exert antibacterial effects by interfering with microbial metabolism. This limitation based on the category of chemical components ensures that the selected plant-derived components have clear chemical action sites and functional orientation. For example, in scenarios targeting mixed odor sources (such as ammonia, indole, and odor-producing bacteria), using a combination of phenolic and terpenoid components can synergistically treat different types of odor sources from both chemical reaction and antibacterial perspectives.

[0034] In some specific embodiments, the natural plant-derived deodorizing and antibacterial agent is selected from one or more of the following: persimmon tannin, tea tree oil, sophora flavescens extract, coptis chinensis extract, eugenol, thymol, cinnamaldehyde, citral, carvacrol, 1,8-cineole, menthol, rosemary extract, grapefruit peel extract, honeysuckle extract, scutellaria baicalensis extract, and artemisia argyi oil. To further improve the broad-spectrum deodorizing and antibacterial effects, the ingredients can be optimized and compounded according to the target odor source and applicable scenario. For example, persimmon tannin, due to its high molecular weight condensation structure rich in phenolic hydroxyl groups, has excellent chemical reaction removal capabilities for both nitrogen-containing (such as ammonia and indole) and sulfur-containing (such as hydrogen sulfide and methanethiol) malodorous molecules, and also possesses strong antibacterial properties. When this persimmon tannin is loaded onto a porous starch carrier to form a powder and applied to the functional shell layer, its 2-hour dark-state removal rates for methanethiol and indole can reach 82% and 78%, respectively. In this embodiment, the natural plant-derived deodorizing and antibacterial agent is usually present in the functional shell in powder form. It can be made into powder particles with a particle size of 0.5-5μm by adsorption onto porous starch or cyclodextrin carrier.

[0035] In some embodiments, the microcapsule flavor refers to a flavor inclusion complex prepared by a saturated aqueous solution method using β-cyclodextrin as the wall material, with a flavor encapsulation rate of 60-85% and a particle size of 0.5-3 μm, but it is not limited to this.

[0036] In some embodiments, the functional shell layer further includes a shell matrix material; the shell matrix material accounts for 5%-15% of the mass of the functional shell layer. The shell matrix material (such as sodium alginate or sodium carboxymethyl cellulose) acts as a binder, its core function being to firmly bond submicron-sized particles containing various functional components such as bioenzymes, natural plant-derived deodorizing and antibacterial agents, and microcapsule fragrances together, forming a mechanically stable integral shell layer to prevent detachment during use (such as spraying or friction). For example, when the concentration of sodium alginate is controlled at 10 wt% and applied to fluidized bed coating via bottom spraying, it can form a uniform and dense shell film on the surface of the core layer wrapped by the inner isolation layer, effectively embedding the aforementioned functional components within it. If the amount of matrix material is too low (e.g., <5%), the shell layer bonding force is weak and it is prone to pulverization; if the amount is too high (e.g., >15%), it will over-fill the shell layer pores, hindering the diffusion of odor molecules into the components inside the shell layer.

[0037] In this embodiment, the shell matrix material is selected from one or more of sodium alginate and sodium carboxymethyl cellulose. Sodium alginate is a natural polysaccharide with excellent film-forming properties and biocompatibility, and can form a high-viscosity solution after dissolving in aqueous solution; sodium carboxymethyl cellulose has good water solubility and dispersion stability. Both can provide suitable viscosity to fix the functional components. In a specific implementation, a 10wt% sodium alginate aqueous solution is selected as a binder, and the composite functional powder (enzyme particles, deodorizing and antibacterial powder, fragrance microcapsules) is uniformly coated on the core particles with an inner isolation layer by bottom spraying using a fluidized bed coating machine. The gel-like matrix formed by sodium alginate not only provides structural support, but its hydrophilicity also helps to provide a hydration environment for the enzymes in the shell under spray application conditions, promoting the recovery of enzyme protein activity.

[0038] In some embodiments, the outer insulating layer is composed of porous silica with a thickness of 20-100 nm and a pore size of 1-5 nm. The porous silica outer insulating layer is deposited on the surface of the functional shell using a sol-gel method. Its nanoscale thickness (20-100 nm) and small pore size (1-5 nm) form a porous thin-film barrier. This structure primarily allows small molecule odor gases (such as NH3, with a molecular dynamic diameter of approximately 0.26 nm; H2S, approximately 0.36 nm) to preferentially pass through through the pore size sieving effect, while simultaneously slowing down the outward diffusion rate of microcapsule fragrances in the functional shell to a certain extent, thus achieving a long-lasting sustained release of the fragrance.

[0039] In some embodiments, the submicron-sized particles coating the bioenzyme have a particle size D50 of 1-3 μm. This submicron size endows the enzyme particles with an extremely high specific surface area (up to 5-20 m²). 2Compared to conventional millimeter-sized enzyme particles, its specific surface area is increased by hundreds of times (per g). This characteristic significantly increases the contact area and reaction probability between the enzyme particles and gaseous odor-producing substances (such as methanethiol and indole) in a dry state, making it particularly suitable for air purification and fabric deodorization applications in non-humid environments. For urea hydrolysis scenarios, using urease particles with a D50 of 1.8 μm significantly improves the accessibility of its catalytic active sites, thereby enabling efficient decomposition of odor-producing substances from urea in a short time.

[0040] The microcapsule fragrance has a particle size of 0.5-3 μm. This smaller particle size helps the fragrance particles disperse evenly within the functional shell, reducing localized accumulation and ensuring consistent fragrance release. Simultaneously, this particle size range is suitable for spray applications, preventing deposition or clogging during spraying due to excessively large particles. Assuming the use of β-cyclodextrin as the wall material to encapsulate citrus fragrance microcapsules with a particle size distribution of 0.5-3 μm and an encapsulation efficiency of approximately 75%, these microcapsules can be uniformly mixed with other functional powders (such as enzyme particles and natural plant-derived deodorizing / antibacterial agents) during fluidized bed coating to jointly construct the functional shell.

[0041] In some embodiments, the average particle size D50 of the deodorizing particles is 10-15 μm, and D90 ≤ 20 μm. Controlling the overall particle size distribution is crucial for ensuring performance in end products, especially aerosol products. A D50 within the 10-15 μm range ensures that the particles have sufficient aerodynamic diameter to settle and cover the target surface (such as fabric) without causing them to settle too quickly or clog the nozzle (orifice diameter is typically 0.5-1 mm) during spraying due to excessively large particle size. The limitation of D90 ≤ 20 μm further ensures the concentration of the particle size distribution, avoiding the presence of a small number of large particles.

[0042] In some embodiments, a method for preparing deodorizing particles based on a core-shell structure is also provided, such as... Figure 1 As shown, it includes the following steps: S10. Porous zinc oxide microspheres are prepared in advance by hydrothermal-calcination method, wherein the porous zinc oxide microspheres serve as the core layer; S20. The porous zinc oxide microspheres are dispersed in an inner isolation layer material solution and dried to form an inner isolation layer on the surface of the porous zinc oxide microspheres. S30. The functional shell material is mixed and coated onto the surface of the inner isolation layer, and then dried to form a functional shell. S40. An outer isolation layer is coated on the surface of the functional shell layer, and the deodorizing particles based on the core-shell structure are obtained after drying.

[0043] Specifically, in step S10, zinc acetate is used as the zinc source and hexamethylenetetramine as the alkali-releasing agent, and the reaction is carried out in a hydrothermal reactor in the presence of sodium citrate template agent. The temperature of the hydrothermal reaction is controlled at 100-160 ℃, which is conducive to the nucleation and self-assembly of ZnO nanosheets. After the reaction is completed, the nanosheets are washed, dried, and then calcined in air at 350-500 ℃ for 2-4 hours to remove the template agent and crystallize, finally obtaining zinc oxide microspheres with a hierarchical porous structure. In this embodiment, the calcination temperature and time directly affect the crystal form, specific surface area, and pore structure of zinc oxide, thereby affecting its adsorption performance.

[0044] In step S20, the inner isolation layer material solution is an aqueous solution of cyclodextrin or modified starch, with a concentration of 5-15 wt% to ensure sufficient adhesion and film-forming properties. The porous zinc oxide microspheres are dispersed in an aqueous solution containing 5-15 wt% cyclodextrin or modified starch, ultrasonically dispersed evenly, and the solvent is slowly evaporated to a viscous paste under stirring at 60-80°C. The mixture is then vacuum dried at 40-60°C, ground, and sieved to obtain the core layer particles coated with the inner isolation layer (ZnO@inner isolation layer).

[0045] Before step S30, submicron-sized particles coated with bio-enzymes and natural plant-derived deodorizing and antibacterial powder are first prepared. The preparation of submicron-sized particles coated with bio-enzymes includes the following steps: urease and lipase are dissolved in a pH 7.0 phosphate buffer at a mass ratio of 1:0.5-2 to prepare a solution with a total protein concentration of 3-8 wt%; hydroxypropyl methylcellulose is dissolved in an ethanol-water mixed solvent (volume ratio 1:0.5-2) to prepare a 2-5 wt% solution; the enzyme solution and HPMC solution are mixed evenly at a mass ratio of 1:1-3; spray drying is performed using a nano-spray dryer (e.g., BÜCHI B-90): inlet air temperature 100-120℃, atomization frequency 100-120kHz, outlet air temperature 60-75℃, and submicron-sized particles coated with enzyme are collected, with a particle size D50 of 1-3 μm and an enzyme activity retention rate ≥85%. The preparation of natural plant-derived deodorizing and antibacterial powder includes the following steps: Plant-derived deodorizing and antibacterial agents (such as persimmon tannin extract, a compound of tea tree oil and sophora flavescens extract, eugenol, cinnamaldehyde, etc.) are loaded onto a porous carrier via adsorption. Specifically, the plant-derived deodorizing / antibacterial agent is dissolved in an appropriate amount of ethanol or water, uniformly sprayed onto a porous starch or β-cyclodextrin carrier, stirred evenly, vacuum dried at 40-60℃, ground and sieved to obtain a deodorizing / antibacterial powder with a particle size of 0.5-5 μm. In step S30, the submicron-sized particles coated with bio-enzymes, natural plant-derived deodorizing and antibacterial agents, and microcapsule fragrances are mixed at a mass ratio of 1:(0.5-2):(1-3) to obtain a composite functional powder. The core particles coated with the inner isolation layer are placed in a fluidized bed, and the composite functional powder is uniformly coated on the particle surface by bottom spraying with an aqueous solution containing 3-8 wt% of the shell matrix material (e.g., sodium alginate aqueous solution) as a binder. The air inlet temperature is 50-70℃, and the particles are dried to obtain ZnO@inner isolation layer@functional shell particles.

[0046] In step S40, an outer isolation layer is deposited on the surface of the functional shell layer using a sol-gel method. The particles with the constructed functional shell layer are dispersed in anhydrous ethanol, and ammonia is added to adjust the pH to an alkaline environment of 9-10. An ethanol solution of tetraethyl orthosilicate (TEOS) is slowly added dropwise under stirring. TEOS undergoes hydrolysis and condensation under alkaline conditions, and the resulting silica sol is deposited on the particle surface to form a porous film. After reacting for 2-6 hours, the particles are centrifuged, washed, and dried to obtain deodorizing particles with a final average particle size (D50) of 10-15 μm and a D90 ≤ 20 μm based on a core-shell structure. The thickness of the SiO2 film formed in this process can be precisely controlled by the amount of TEOS added and the reaction time.

[0047] In some embodiments, an application of the core-shell structure-based deodorizing particles as described in this invention is also provided, wherein the deodorizing particles are used to prepare air fresheners, fabric deodorizers, shoe and sock deodorizers, pet deodorizers, laundry detergent deodorizers, or refrigerator deodorizers.

[0048] The present invention will be further explained and illustrated below through specific embodiments: Preparation Example 1: Preparation of Porous Zinc Oxide Microspheres (Core Layer) 4.39 g of zinc acetate dihydrate was dissolved in 100 mL of deionized water; 2.80 g of hexamethylenetetramine and 0.15 g of sodium citrate were dissolved in 100 mL of deionized water; the latter was added dropwise to the former under vigorous stirring, and stirring was continued for 1 hour; the mixture was transferred to a 200 mL autoclave (70% filling) and hydrothermally reacted at 120 °C for 12 hours; after cooling, the product was washed three times each by alternating centrifugation with deionized water and anhydrous ethanol, and dried at 60 °C for 12 hours; calcined in air at 450 °C at a rate of 1.5 °C / min for 3 hours to obtain porous zinc oxide microspheres. The specific surface area was 68 m² / g according to BET analysis. SEM characterization (e.g.) was performed. Figure 2-5 As shown in the figure, the microspheres are formed by the self-assembly of nanosheets, with a diameter of 0.5-8 μm and a particle size distribution D50 of approximately 2.8 μm.

[0049] Preparation Example 2: Preparation of bioenzymes coated with submicron-sized particles Urease (50000U / g) and lipase (30000U / g) were dissolved in pH 7.0 phosphate buffer at a mass ratio of 1:1 to prepare a total protein concentration of 5wt%; hydroxypropyl methylcellulose was dissolved in an ethanol-water (1:1) mixed solvent to prepare a 3wt% solution; the enzyme solution and HPMC solution were mixed evenly at a mass ratio of 1:2.

[0050] The enzyme was prepared using a nano-spray dryer (BÜCHI B-90): inlet air temperature 110℃, atomization frequency 110kHz, and outlet air temperature 65℃. White, submicron-sized powder-like particles coated with the enzyme were collected. SEM showed that the particles were spherical, with a particle size range of 0.5-4.5μm and a D50 of approximately 1.8μm. Enzyme activity tests showed a urease retention rate of 90% and a lipase retention rate of 87%.

[0051] Preparation Example 3: Plant-derived deodorizing / antibacterial powder Powder A (Persimmon Tannin): Dissolve persimmon tannin extract (tannin content ≥80%) in deionized water to prepare a 10wt% solution, spray it evenly onto porous starch (persimmon tannin to porous starch mass ratio 1:3), stir and mix evenly, vacuum dry at 50℃, grind and pass through an 800-mesh sieve to obtain persimmon tannin deodorizing / antibacterial powder A with a particle size range of 0.5-5μm; Powder B (compound of tea tree oil and sophora flavescens extract): Dissolve tea tree oil and sophora flavescens extract in a small amount of ethanol at a mass ratio of 1:2, spray evenly on porous starch, vacuum dry at 40℃, grind through an 800-mesh sieve to obtain antibacterial powder B with a particle size range of 0.5-3μm. Powder C (eugenol): Eugenol is dissolved in a small amount of ethanol and sprayed evenly onto β-cyclodextrin (eugenol to β-cyclodextrin mass ratio 1:3), dried under vacuum at 40℃, and ground through an 800-mesh sieve to obtain antibacterial powder C with a particle size range of 0.5-3μm. Powder D (cinnamaldehyde): Cinnamaldehyde is dissolved in a small amount of ethanol and sprayed evenly onto porous starch (the mass ratio of cinnamaldehyde to porous starch is 1:5). It is then vacuum dried at 40°C and ground through an 800-mesh sieve to obtain antibacterial powder D with a particle size range of 0.5-3μm.

[0052] Preparation Example 4: Microencapsulated Flavor Citrus flavoring was prepared by encapsulating citrus flavoring with a saturated aqueous solution of β-cyclodextrin. 10 g of β-cyclodextrin was dissolved in 100 mL of deionized water and stirred in a 50°C water bath. 2 g of citrus flavoring (containing a small amount of ethanol for dissolution) was slowly added dropwise while stirring, and the encapsulation was continued for 2 hours. After cooling, the mixture was placed in a 4°C refrigerator and allowed to stand for 12 hours. The mixture was then filtered, washed once with a small amount of deionized water and once with anhydrous ethanol, dried under vacuum at 40°C for 6 hours, and ground through an 800-mesh sieve to obtain a white powdery microcapsule flavoring. The encapsulation efficiency was approximately 75%, and the particle size range was 0.5-3 μm.

[0053] Example 1: Deodorizing granules with a core-shell structure containing persimmon tannins A method for preparing core-shell structured deodorizing particles, comprising: Step 1 (Inner isolation layer coating): Take 10.0 g of porous zinc oxide microspheres prepared in Example 1, disperse them in 100 mL of an aqueous solution containing 10 wt% sodium octenyl succinate starch, and sonicate for 30 minutes; stir at 70 °C to evaporate the solvent until a viscous paste is formed; vacuum dry at 50 °C for 12 hours, grind through a 400 mesh sieve to obtain ZnO@inner isolation layer particles.

[0054] Step 2 (Construction of Functional Shell): The submicron-sized particles coated with enzyme prepared in Preparation Example 2, the persimmon tannin deodorizing and antibacterial powder A prepared in Preparation Example 3, and the microcapsule fragrance prepared in Preparation Example 4 were mixed at a mass ratio of 1:2:2 to obtain a composite functional powder; 10.0 g of ZnO@inner isolation layer particles were placed in a fluidized bed coating machine, and 8.0 g of composite functional powder was uniformly coated on the particle surface using a bottom spray method with a 5wt% sodium alginate aqueous solution as a binder. The air inlet temperature was 60℃, and the particles were dried to obtain ZnO@inner isolation layer@functional shell particles.

[0055] Step 3 (Outer Insulation Layer Deposition): Disperse 5.0 g of the above ZnO@inner Insulation Layer@functional Shell particles in 50 mL of anhydrous ethanol, add 2 mL of ammonia (25 wt%), and slowly dropwise add 0.3 mL of tetraethyl orthosilicate in 10 mL of ethanol solution while stirring. React at room temperature for 4 hours; centrifuge, wash three times with ethanol, and dry at 60 °C to obtain the final core-shell structured deodorizing particles. The average particle size (D50) measured by a laser particle size analyzer is 12.5 μm, D10 = 6.3 μm, and D90 = 18.8 μm.

[0056] Example 2: Core-shell deodorizing granules containing tea tree oil / Sophora flavescens extract A method for preparing core-shell structured deodorizing particles, which differs from Example 1 only in the plant-derived deodorizing and antibacterial agent used in the functional shell layer. Specifically, persimmon tannin powder A in step two is replaced with powder B (a compound of tea tree oil and sophora flavescens extract) obtained in Preparation Example 3. The functional particle ratio is adjusted to submicron-sized particle-encapsulated enzyme: antibacterial powder B: microcapsule fragrance = 1:1:2. All other steps and parameters are identical to those in Example 1. The resulting particles have a D50 of 12.8 μm and a D90 of 18.2 μm.

[0057] Example 3: Core-shell deodorizing granules containing eugenol A method for preparing core-shell structured deodorizing particles is disclosed. The steps are identical to those in Example 1, except that the plant-derived deodorizing and antibacterial agent used in the functional shell is eugenol. Specifically, persimmon tannin powder A in step two is replaced with powder C (eugenol) obtained in Preparation Example 3. All other steps and parameters are exactly the same as in Example 1. The resulting particles have a D50 of 11.9 μm and a D90 of 17.5 μm.

[0058] Example 4: Core-shell structured deodorizing granules containing a blend of persimmon tannins and tea tree oil A method for preparing core-shell structured deodorizing particles, which differs from Example 1 in that a composite plant-derived deodorizing and antibacterial agent is used in the functional shell layer. Specifically, in step two, persimmon tannin powder A and antibacterial powder B are mixed at a mass ratio of 1:1, and then mixed with submicron-sized particle-coated enzyme and microcapsule fragrance at a mass ratio of 2:1:2 (i.e., enzyme:composite plant powder:fragrance = 1:2:2). The remaining steps and parameters are exactly the same as in Example 1. The resulting particles have a D50 of 13.2 μm and a D90 of 19.4 μm.

[0059] Comparative Example 1: Simple Physical Mixtures A method for preparing deodorizing granules includes the following steps: according to the same mass ratio as in Example 1, weigh porous zinc oxide microspheres, unencapsulated enzyme lyophilized powder (urease + lipase, ratio 1:1), persimmon tannin powder A (for direct use, unloaded), and fragrance microcapsules, and simply physically grind and mix them evenly in a mortar. The mixture does not have any hierarchical structure.

[0060] Comparative Example 2: Inner isolation layer omitted A method for preparing deodorizing particles differs from Example 1 in that step one (not covering the inner isolation layer) is omitted. Instead, steps two (functional shell construction) and three (outer isolation layer deposition) are carried out directly on the surface of bare porous zinc oxide microspheres via a fluidized bed. The remaining steps and parameters are exactly the same as in Example 1.

[0061] Comparative Example 3: Outer isolation layer omitted A method for preparing deodorizing particles, the steps of which are the same as those in Example 1, except that step three (depositing the outer isolation layer) is omitted. The particle structure from the inside out is: core layer, inner isolation layer, and functional shell layer. The remaining steps and parameters are exactly the same as those in Example 1.

[0062] Comparative Example 4: The functional shell does not contain persimmon tannins. A method for preparing deodorizing granules, the steps of which are the same as those in Example 1, except that the persimmon tannin powder A in the functional shell is replaced with an equal amount of blank porous starch, while the remaining steps and parameters are exactly the same as those in Example 1.

[0063] Comparative Example 5: Core layer using ordinary zinc oxide A method for preparing deodorizing granules, the steps of which differ from those in Example 1, is that the porous zinc oxide microspheres in the core layer are replaced with an equal mass of commercially available ordinary zinc oxide powder (non-porous structure, specific surface area of ​​approximately 5 m²). 2 / g), the remaining steps and parameters are exactly the same as in Example 1, but the substrate covered by the inner isolation layer changes due to the replacement of the core layer.

[0064] To fully verify the superiority of the core-shell structure particles of the present invention, systematic performance tests were conducted on the above embodiments and comparative examples, including dark-state deodorization performance, enzyme activity stability, fragrance sustained-release performance, antibacterial effect, and spray permeability.

[0065] Experiment 1: Dark-state deodorization performance test Test Method: The test method was specified in GB / T 33610.1-2019 "Determination of Deodorizing Properties of Textiles - Part 1: General Rules". 0.5g samples were placed in 5L Tedlar sampling bags, and a single odor source gas (ammonia, hydrogen sulfide, acetic acid, 2-nonenal, methanethiol, indole) with an initial concentration of approximately 50 ppm was injected. The bags were sealed and allowed to stand in the dark for 2 hours. The concentration of the odor source substance in the sampling bag after 2 hours was measured using the corresponding detection tube or gas chromatograph, and the concentration reduction rate (%) was calculated. Each sample was tested three times, and the average value was taken. The results are shown in Table 1.

[0066] Table 1. Reduction rate of odor source concentration (%, 2 hours) under dark conditions

[0067] The following conclusions can be drawn from the data in Table 1: Comparison of Hierarchical Structure and Simple Mixing: Compared with a simple physical mixture of the same components (Comparative Example 1), the four-layer core-shell structure particles of the present invention (Example 1) showed significantly higher deodorization rates for all six tested odor sources. For example, the deodorization rate was increased by 19 percentage points for ammonia (95% vs 76%), by 17 percentage points for hydrogen sulfide (96% vs 79%), by 27 percentage points for 2-nonenal (85% vs 58%), by 27 percentage points for methanethiol (82% vs 55%), and by 28 percentage points for indole (78% vs 50%). This fully demonstrates that the present invention, through the design of an ordered hierarchical structure of outer, middle, and inner layers, allows odor molecules to pass sequentially through the outer isolation layer for sieving, the functional shell layer for multiple reactions, and the core layer for strong neutralization, achieving synergistic effects among the functional components and eliminating disordered competition and mutual interference in simple mixing systems. This synergistic effect of 1+1>2 is unparalleled by simple composite or single structures in the prior art.

[0068] The unique contribution of persimmon tannin: Comparing Example 1 (containing persimmon tannin) and Comparative Example 4 (without persimmon tannin, replaced by starch), it can be found that persimmon tannin significantly improves the removal effect of organic odor-causing substances. With other components of the functional shell layer (enzymes, fragrances) remaining the same, the addition of persimmon tannin increased the removal rate of 2-nonenal from 72% to 85%, methanethiol from 65% to 82%, and indole from 60% to 78%. This clearly demonstrates that persimmon tannin, through its abundant phenolic hydroxyl groups, effectively captures complex organic odor molecules that are difficult to efficiently treat by physical adsorption and enzymatic hydrolysis alone, through multiple chemical reactions such as neutralization, hydrogen bonding, and inclusion. While existing technologies disclose the deodorizing function of persimmon tannin, none have combined it with the porous zinc oxide core layer, enzymes, etc., of this invention and placed it within a hierarchically ordered core-shell structure. This invention places persimmon tannin in a functional shell layer, allowing it to undergo a chemical reaction before odor molecules penetrate deeper. This utilizes its broad spectrum of activity while avoiding direct contact with ZnO (separated by an inner insulating layer), achieving a perfect integration of functions.

[0069] Synergistic effect of porous ZnO and persimmon tannins: Comparing Example 1 and Comparative Example 5, an important synergistic effect can be found. Example 1 used a high specific surface area (68m²) 2 Comparative Example 5 used a porous ZnO core layer with a specific surface area of ​​approximately 5 m² / g. 2 The core layer of Comparative Example 5 was a standard ZnO sample (g), with the same functional shell (containing persimmon tannin). Results showed that Comparative Example 5 had significantly lower removal rates for all odor sources, especially for inorganic small molecule gases (ammonia, hydrogen sulfide) and organic odor sources (methanethiol, indole), compared to Example 1. This demonstrates that porous ZnO, through its strong physical adsorption capacity, rapidly enriches odor molecules within the particles, forming a high-concentration micro-region. This micro-region not only facilitates chemical neutralization of ZnO itself but also indirectly increases the collision probability between persimmon tannin molecules and odor molecules in the functional shell, thereby accelerating the chemical reaction rate. Conversely, persimmon tannin removes organic sulfur and organic amines, which have weaker adsorption capacity in porous ZnO, freeing up ZnO's active sites and allowing it to focus more on treating small molecule inorganic gases. The two form a perfect synergistic chain of physical enrichment and chemical reaction.

[0070] Experiment 2: Enzyme activity stability test (accelerated aging) Test Method: 5g of samples from Example 1, Comparative Example 1, and Comparative Example 2 were sealed and stored in a constant temperature and humidity chamber (40℃, 75% RH). Samples were taken on day 0 and day 30. Since urease and lipase are both proteins and sensitive to metal ions, lipase was used as the representative for activity determination in this test. The residual activity of lipase in each sample was determined using a lipase activity assay kit (colorimetric method). The activity on day 0 was taken as 100%, and the activity retention rate (%) after 30 days was calculated. The results are shown in Table 2.

[0071] Table 2. Lipase activity retention rate (%)

[0072] The results in Table 2 demonstrate the core inventive point of this invention. In Comparative Example 1 (simple mixing), the enzyme was in direct contact with porous ZnO. Under accelerated aging conditions of high temperature and high humidity, Zn... 2+ The rapid dissolution and attack of enzyme molecules led to a drastic decrease in enzyme activity, with a retention rate of only 32% after 30 days. This confirms the problem that ZnO and enzymes cannot coexist easily in the existing technology.

[0073] In Comparative Example 2 (without an inner insulating layer), although the functional shell (containing enzymes) directly coats the ZnO core and there is an outer insulating layer, it still cannot prevent Zn from entering the nucleus. 2+ After 30 days, the retention rate of Zn was 51%, which was better than simple mixing, but nearly half of the activity was still lost. This indicates that the encapsulation by the shell matrix alone is insufficient to completely isolate Zn. 2+ Its toxic effects.

[0074] In Example 1 (with an inner barrier), the introduction of an inner barrier composed of sodium octenyl succinate starch between the ZnO core and the functional shell resulted in excellent protection of enzyme activity, with a retention rate as high as 86% after 30 days. This strongly demonstrates that the inner barrier, acting as a physical barrier, effectively blocks ZnO. 2+ The diffusion into the shell ensures the long-term stable coexistence of the enzyme and ZnO, two chemically incompatible but functionally complementary components, within the same particle. This invention, through an ingenious four-layer structure design, achieves for the first time a stable and synergistic encapsulation of a strong inorganic adsorbent / neutralizing agent (porous ZnO) and a fragile biomolecular catalyst (enzyme) within the particle—a feat that would not be easily conceived by those skilled in the art based on existing technology.

[0075] Experiment 3: Fragrance sustained-release performance test Test Method: Ten trained sensory evaluators were randomly selected. 0.5g samples from Example 1, Comparative Example 1, and Comparative Example 3 were placed in open glass dishes and left to stand naturally at room temperature (25°C). Evaluators scored the aroma intensity of the samples at the initial (0h), 24h, 48h, and 72h times, using a 5-point scale (5 being the strongest, 1 being odorless). The average score from the ten evaluators was taken. The results are shown in Table 3.

[0076] Table 3. Aroma intensity changes over time (sensory evaluation by 10 people, on a 5-point scale)

[0077] The following conclusions can be drawn from the data in Table 3: The aroma-preserving effect of the inner isolation layer: Comparing Example 1 (initial aroma 4.5) and Comparative Example 1 (initial aroma 2.8), both used the same amount of fragrance microcapsules, but the initial aroma intensity of Example 1 was much higher than that of Comparative Example 1. This is because in the simple mixture of Comparative Example 1, after the fragrance molecules were released from the microcapsules, they were immediately adsorbed and retained by the porous ZnO powder with extremely strong adsorption capacity, preventing most of the fragrance from evaporating into the air. In Example 1, however, the inner isolation layer acted as a physical barrier, preventing the fragrance molecules released from the functional shell from diffusing into the porous ZnO core layer, allowing them to evaporate smoothly. This fully demonstrates that the aroma-preserving function of the inner isolation layer is another unexpected beneficial effect.

[0078] The sustained-release effect of the outer isolation layer: Comparative Example 1 and Comparative Example 3 (without the outer isolation layer), both had the same initial aroma intensity (4.5), proving that the outer isolation layer does not affect the release of fragrance in the initial stage. However, over time, the aroma intensity of Comparative Example 3 decayed faster, dropping to 1.5 after 72 hours, while Example 1 still had 2.8. This indicates that the porous silica film on the outer layer effectively controls the outward release rate of fragrance molecules through the diffusion confinement effect of its nanopores (1-5 nm), achieving long-lasting fragrance retention. The inner isolation layer preserves fragrance, while the outer isolation layer provides sustained release; the two work synergistically to solve the two long-standing problems in the field: adsorbent-induced fragrance locking and short-lived aroma.

[0079] Experiment 4: Antibacterial effect test Test method: 0.1g of the functional shell powder from Example 1 (containing persimmon tannin), Example 2 (containing tea tree oil + sophora flavescens extract), and Comparative Example 4 (functional shell without deodorizing / antibacterial agents) were taken and respectively mixed with 1mL of Staphylococcus aureus and Escherichia coli bacterial suspension (approximately 10 mL). 6The mixture was prepared by contact incubation at 37°C for 6 hours. The number of surviving colonies was determined using the plate count method, and the inhibition rate (%) was calculated. Sterile physiological saline was used as a blank control. Results are shown in Table 4.

[0080] Table 4. Antibacterial rate (%)

[0081] Table 4 shows that Examples 1 and 2 both exhibited extremely excellent antibacterial effects, with inhibition rates exceeding 99% against two common odor-producing microorganisms, far higher than Comparative Example 4 (which did not contain plant-derived deodorizing / antibacterial agents and had an inhibition rate of only about 10%). This proves that the natural plant-derived components (persimmon tannin, tea tree oil / Sophora flavescens extract) selected in this invention can effectively exert their antibacterial function in the functional shell. Dual-function integration: In particular, persimmon tannin plays a dual role in this invention as both a deodorizer (through chemical reaction) and an antibacterial agent (by destroying microorganisms). This multifunctionality allows this invention to achieve two effects with a single component, simplifying the formulation, improving the stability of the shell, and inhibiting the growth of odor-producing microorganisms. It fundamentally blocks the generation of certain types of odors (such as foot odor and body odor) at the source, which cannot be achieved by relying solely on physical adsorption or chemical reactions. This invention combines source inhibition with end-stage capture / decomposition, forming a more complete deodorization strategy.

[0082] Experiment 5: Spray Passage Test Test method: The core-shell structured deodorizing granules prepared in Example 1 were dispersed in deionized water at a concentration of 5 wt% and placed into a commercially available manual spray bottle (nozzle orifice diameter 0.5 mm). The spray was continuously pressed at a frequency of approximately once per second for 50 sprays, and the smoothness of the spray and the absence of clogging were observed. After 50 sprays, the spray bottle was allowed to stand for 24 hours, and its spray performance was tested again.

[0083] Test results: During 50 consecutive sprays, the spray was smooth without any jamming or blockage. After standing for 24 hours, it could still spray normally and produce uniform droplets.

[0084] Results analysis: The average particle size D50 of the particles of the present invention is 12.5 μm, and D90 is 18.8 μm, with the overall size controlled within 20 μm. The particles are spherical (determined by the preparation process) and have good flowability. This particle size range is perfectly matched with conventional spraying devices (nozzle orifice diameter 0.5-1.0 mm), ensuring convenient application in daily consumer products.

[0085] 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 deodorizing granule based on a core-shell structure, characterized in that, The deodorizing particles, from the inside out, comprise: The core layer is composed of porous zinc oxide microspheres; An inner isolation layer covers the surface of the core layer; A functional shell layer is formed on the surface of the inner isolation layer. The functional shell layer contains submicron-sized particles encapsulating biological enzymes, natural plant-derived deodorizing and antibacterial agents, and microcapsule fragrances. An outer isolation layer is applied to the surface of the functional shell layer.

2. The deodorizing granules based on a core-shell structure according to claim 1, characterized in that, The core layer accounts for 20-50% of the total mass of the deodorizing particles, the inner isolation layer accounts for 2-8% of the total mass of the deodorizing particles, the functional shell layer accounts for 30-60% of the total mass of the deodorizing particles, and the outer isolation layer accounts for 1-3% of the total mass of the deodorizing particles.

3. The deodorizing granules based on a core-shell structure according to claim 1, characterized in that, The porous zinc oxide microspheres have a diameter of 0.5-8 μm, a BET specific surface area of ​​40-100 m² / g, and a bimodal pore size distribution of 2-15 nm mesopores and 30-100 nm macropores.

4. The deodorizing granules based on a core-shell structure according to claim 1, characterized in that, The inner isolation layer is selected from at least one of cyclodextrin-based materials and modified starch materials.

5. The deodorizing granules based on a core-shell structure according to claim 1, characterized in that, The outer insulating layer is composed of porous silicon dioxide.

6. The deodorizing granules based on a core-shell structure according to any one of claims 1-5, characterized in that, The submicron-sized particles coated with bioenzymes are urease and / or lipase; and the submicron-sized particles coated with bioenzymes use modified cellulose as the wall material.

7. The deodorizing granules based on a core-shell structure according to any one of claims 1-5, characterized in that, The natural plant-derived deodorizing and antibacterial agent is selected from at least one of phenolic plant-derived components, terpenoid plant-derived components, and alkaloid plant-derived components.

8. The deodorizing granules based on a core-shell structure according to claim 7, characterized in that, The natural plant-derived deodorizing and antibacterial agent is selected from one or more of the following: persimmon tannin, tea tree oil, sophora flavescens extract, coptis chinensis extract, eugenol, thymol, cinnamaldehyde, citral, carvacrol, 1,8-cineole, menthol, rosemary extract, grapefruit peel extract, honeysuckle extract, scutellaria baicalensis extract, and artemisia argyi oil.

9. A method for preparing deodorizing particles based on a core-shell structure as described in any one of claims 1-8, characterized in that, Including the following steps: Porous zinc oxide microspheres were prepared in advance by a hydrothermal-calcination method, and the porous zinc oxide microspheres served as the core layer. The porous zinc oxide microspheres are dispersed in an inner isolation layer material solution and dried to form an inner isolation layer on the surface of the porous zinc oxide microspheres. The functional shell material is coated onto the surface of the inner isolation layer and dried to form the functional shell. The deodorizing particles based on the core-shell structure are obtained by coating the surface of the functional shell layer with an outer isolation layer and drying it.

10. An application of deodorizing particles based on a core-shell structure as described in any one of claims 1-8, characterized in that, The deodorizing granules can be used to prepare air fresheners, fabric deodorizers, shoe and sock deodorizers, pet deodorizers, laundry deodorizers, or refrigerator deodorizers.

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