Nanocomposite antibacterial and deodorant cat litter and preparation method thereof

Abstract

The present application relates to pet chemicals technology, aiming at providing a kind of nanocomposite antibacterial deodorization cat litter and its preparation method.The method comprises: Zn-CA complex solution is added dropwise to polyvinyl alcohol pre-occupancy bentonite suspension, reaction is carried out under the condition of heating and stirring, so that zinc complex realizes slow release and uniform distribution;After adjusting the pH value of reaction system, it is placed finally to form solid block wet gel;After drying and crushing treatment, it is placed in muffle furnace and calcined, and nanometer zinc oxide@bentonite composite particles are obtained after cooling.The present application is based on the construction of composite particles of "two-component synergistic competitive adsorption" system, and can realize antibacterial, adsorption and deodorization triple functions through "bacteriostasis-adsorption-transformation" triple action mechanism, to block odor generation and bacterial propagation from source;Product is well compatible with cat litter base material, grouping agent and the like;Product preparation process is simple, mild and controllable, safe, non-toxic, environment-friendly.

Description

Technical Field

[0001] This invention relates to the field of pet chemical products technology, specifically to a nanocomposite antibacterial and deodorizing cat litter and its preparation method. The product has highly efficient antibacterial and deodorizing functions. Background Technology

[0002] Cat excrement is rich in organic matter such as urea, amines, and thiols, which easily decompose under the action of microorganisms to produce malodorous substances such as ammonia and hydrogen sulfide. This not only causes strong irritation but also easily breeds bacteria and pathogens, posing a dual threat to indoor environmental hygiene and pet health. As a daily grooming product, the deodorizing and antibacterial properties of cat litter directly affect the user experience. Currently, most commercially available cat litters rely on physical adsorption deodorization using materials such as bentonite and activated carbon. Some researchers and manufacturers have also tried adding antibacterial agents such as silver ions (e.g., patent CN114424751A) and quaternary ammonium salts (e.g., patent CN120858884A) to the litter. However, these additives often have shortcomings such as weak antibacterial properties, easy inactivation and oxidation, and weak ability to chemically convert odor molecules, resulting in incomplete deodorization and recurring odors.

[0003] In recent years, nano-zinc oxide (ZnO) has been regarded as an ideal antibacterial and deodorizing material due to its excellent photocatalytic activity, slow-release antibacterial properties, and chemical adsorption and conversion capabilities for sulfur- and nitrogen-containing odor molecules. Theoretically, combining it with bentonite, which has a high specific surface area and adsorption capacity, can create a composite system with antibacterial, adsorption, and conversion functions for use in cat litter, thereby inhibiting odor generation at its source. Publicly available literature reports on the use of nano-zinc oxide combined with bentonite for sterilization and deodorization, with mainstream preparation methods including solution impregnation, co-precipitation, and hydrothermal synthesis. Among these, solution impregnation is simple, relying mainly on physical adsorption, resulting in the weakest binding force and poor dispersibility, with nanoparticles easily detaching. In-situ precipitation is a classic industrial preparation method with a relatively simple process, but dispersibility is generally poor, with easy external independent agglomeration, mostly physical encapsulation, moderate binding force, and potential detachment under friction. Hydrothermal synthesis results in strong adhesion and good dispersibility through in-situ growth, but it requires high-pressure equipment and energy consumption. The preparation process requires high-pressure conditions and the use of a high-pressure reactor.

[0004] While these mainstream technologies offer insights into nanocomposites, they face significant technical limitations when applied to cat litter products. Firstly, nanoparticles tend to agglomerate within the bentonite carrier, leading to a reduction in active sites and uneven functionality, thus affecting the stability and durability of antibacterial and deodorizing effects. Secondly, during cat litter use, lightweight nanoparticles are easily detached and float due to friction and vibration, generating inhalable dust and posing potential health risks. Therefore, they are difficult to directly incorporate into cat litter products that require high levels of safety, dispersion stability, and functionality.

[0005] Therefore, finding a new composite technology suitable for cat litter products, enabling nano zinc oxide to be highly dispersed and firmly fixed in bentonite, in order to solve the current pain points of insufficient antibacterial and deodorizing properties and lack of safety in the use of pet cat litter, has become a key research direction. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a nanocomposite antibacterial and deodorizing cat litter and its preparation method.

[0007] To solve the technical problem, the solution of the present invention is:

[0008] Firstly, a method for preparing nano-zinc oxide-bentonite composite particles is provided, including the following steps:

[0009] (1) Add polyvinyl alcohol aqueous solution dropwise to bentonite suspension and react under heating and stirring conditions to obtain polyvinyl alcohol pre-occupied bentonite suspension;

[0010] (2) Zinc acetate dihydrate and citric acid (CA) are dissolved together in deionized water and stirred at room temperature to form a Zn-citric acid complex solution; then, under stirring conditions, it is added dropwise to a polyvinyl alcohol pre-occupied bentonite suspension and reacted under heating and stirring conditions to achieve slow release and uniform distribution of the zinc complex.

[0011] (3) Under vigorous stirring, continue to add ammonium bicarbonate aqueous solution to the reaction system of step (2) until the pH value rises slowly to 6.5~7.5; then let it stand at room temperature, and the slowly released Zn 2+ Gradually hydrolyzed to generate Zn(OH)2, the reaction system gradually thickens to achieve gelation, and finally forms a solid block wet gel;

[0012] (4) After drying and crushing the wet gel, it is placed in a muffle furnace for calcination and cooled to obtain nano zinc oxide-bentonite composite particles.

[0013] As a preferred embodiment of the present invention, in the raw materials used in steps (1) and (2), the mass ratio of polyvinyl alcohol, bentonite, zinc acetate dihydrate and citric acid is 2~5:10:2~4:2~6 (10 is set based on bentonite).

[0014] As a preferred embodiment of the present invention, polyvinyl alcohol is added to an appropriate amount of deionized water and stirred in a 90 ℃ water bath until completely dissolved to obtain a polyvinyl alcohol aqueous solution; sodium bentonite is added to an appropriate amount of deionized water and stirred vigorously at 1800~2200 rpm for 1 h at room temperature to obtain a bentonite suspension; zinc acetate dihydrate and citric acid are added to an appropriate amount of deionized water and dissolved, and stirred at room temperature for 10 min to form a Zn-citric acid complex solution; ammonium bicarbonate is dissolved in an appropriate amount of deionized water to obtain an ammonium bicarbonate aqueous solution.

[0015] As a preferred embodiment of the present invention, in step (1), the reaction is carried out at 60 °C for 2 h; in step (2), the reaction is carried out at 60 °C for 1 h; in step (3), the vigorous stirring condition refers to stirring at a speed of 1000~1500 rpm and standing time is 12~24 h; in step (4), the drying temperature is 80 °C and the time is 24 h; during calcination, the temperature is increased to 350 °C at a rate of 2 °C / min, held for 2 h, and then cooled to room temperature with the furnace.

[0016] The present invention further provides a nanocomposite antibacterial and deodorizing cat litter, comprising the following raw materials in parts by weight: 65-90 parts of main substrate, 20-40 parts of functional components, 5-15 parts of clumping material, 6-10 parts of binder, 1-5 parts of thickener, and 0-3 parts of additives;

[0017] The main substrate is one or more of cassava starch, soybean fiber, corn cob, and bentonite; the functional component refers to nano-zinc oxide-bentonite composite particles prepared by the aforementioned method; the agglomerating material is one or more of bentonite, corn starch, and potato starch; the binder is one or more of corn starch, guar gum, and maltodextrin; the thickener is one or more of bentonite, cassava starch, and lignocellulose; and the additives are one or more of potassium sorbate, citric acid, food coloring, and plant essential oils.

[0018] This invention also provides a method for preparing the aforementioned nanocomposite antibacterial and deodorizing cat litter, comprising the following steps:

[0019] (1) The functional components are mixed with an appropriate amount of additives and an appropriate amount of binder, and after granulation and air drying, antibacterial and deodorizing functional particles are obtained.

[0020] (2) Add the agglomerating material, thickener, appropriate amount of additives and the remaining adhesive to an appropriate amount of water to make a water-soluble adhesive; after crushing and sieving the main substrate, add it to the water-soluble adhesive and stir to mix; after granulation and drying, obtain the cat litter substrate;

[0021] (3) Mix the cat litter base material and functional particles evenly to obtain a nano-composite antibacterial and deodorizing cat litter product.

[0022] As a preferred embodiment of the present invention, in step (1), granulation refers to granulation by extrusion using a mold, and the temperature for air drying and curing is 40~60 ℃; in step (2), granulation refers to granulation by extrusion using a mold, and the temperature for drying is 60~80 ℃, and the moisture content of the cat litter substrate is less than 10%; in step (3), the cat litter substrate and functional particles are mixed in a weight ratio of 85~70:15~30.

[0023] As a preferred embodiment of the present invention, according to the product formulation design, the additives are added to the cat litter substrate and / or functional particles; the adhesive is an essential component of the cat litter substrate and functional particles, and a portion thereof should be added in steps (1) and (2) respectively.

[0024] As a preferred embodiment of the present invention, the functional particles are spherical particles with a diameter of 4 mm; the cat litter substrate is a long cylindrical particle with a diameter of 2 mm × 20 mm.

[0025] As a preferred embodiment of the present invention, it further includes: using bag-shaped or can-shaped containers to package the nanocomposite antibacterial and deodorizing cat litter product.

[0026] The implementation principle of this invention:

[0027] This invention utilizes a "two-component synergistic competitive adsorption" system composed of polyvinyl alcohol (PVA) and citric acid (CA), and introduces it into the classic sol-gel process. Its innovative core technology lies in the fact that the long chains of PVA will first adsorb onto the bentonite surface, forming a flexible hydrophilic network, which serves to pre-occupy space, isolate aggregation sites, and provide new anchor points (hydroxyl groups); while citric acid reacts with Zn... 2+ A complex is formed, and through dynamic competitive adsorption with active sites on the surfaces of polyvinyl alcohol and bentonite, the slow release and uniform distribution of zinc species are achieved by adjusting the pH. During the subsequent gelation process, the slowly released Zn... 2+ Hydrolysis generates Zn(OH)₂, which dehydrates under the constraint of a polyvinyl alcohol network and citric acid to form ZnO nanocrystals, forming strong chemical covalent bonds (such as Zn-O-Si) on the surface and between layers of bentonite. This invention cleverly utilizes a system of polyvinyl alcohol and citric acid, which, in a temporal and spatial sequence, regulate the anchoring, nucleation, and growth process of nano-zinc oxide on the bentonite surface, achieving high dispersion and strong bonding of nano-zinc oxide on the bentonite surface and between layers.

[0028] After further incorporating this nano-zinc oxide-bentonite composite particle as the core antibacterial and deodorizing unit into cat litter, the Zn in the composite particle... 2+ The antibacterial effect can inhibit the generation of odors at the source, while bentonite will adsorb the generated ammonia and react with Zn. 2+Complexation and fixation. Therefore, this cat litter product can fundamentally solve the problems of odor, bacterial growth and safety during the use of cat litter through a triple synergistic mechanism of "antibacterial inhibition - adsorption enrichment - chemical transformation".

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. In the preparation of nano-zinc oxide-bentonite composite particles, this invention introduces two safe, non-toxic, and low-cost materials, polyvinyl alcohol and citric acid, into the classic sol-gel process. Based on the construction of a "two-component synergistic competitive adsorption" system, this invention overcomes the key technical challenges of easy agglomeration and easy dissociation of nanoparticles, providing a feasible path for the application of nanotechnology in pet daily necessities.

[0031] 2. The nano zinc oxide-bentonite composite particles prepared by this invention achieve antibacterial, adsorption and deodorization functions through a triple mechanism of "antibacterial-adsorption-conversion", blocking the generation of odors and the reproduction of bacteria from the source.

[0032] 3. The composite particles obtained by this invention are highly compatible with cat litter substrates and clumping agents. They not only inherit the water absorption and clumping characteristics of traditional cat litter, but also achieve significant progress in long-lasting antibacterial properties, source deodorization, and safety of use.

[0033] 4. The preparation process of the cat litter product of this invention is simple, mild and under controllable conditions, and has good industrial feasibility; the product is safe, non-toxic and environmentally friendly, meeting the modern family's pursuit of a green and healthy life. Attached Figure Description

[0034] Figure 1 This is a SEM image of the nano-zinc oxide-bentonite composite particles in this invention.

[0035] Figure 2 This is a schematic diagram of the cat litter product in different states according to the present invention.

[0036] (a) shows the original shape and size of the product; (b) shows the instantaneous water absorption state; and (c) shows the clumping state. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments.

[0038] I. Overview of the Invention Technical Solution

[0039] 1. First, the present invention provides a method for preparing nano zinc oxide-bentonite composite particles.

[0040] The preparation method of this composite particle includes the following steps:

[0041] (1) Add polyvinyl alcohol to an appropriate amount of deionized water and stir in a 90 ℃ water bath until completely dissolved to obtain a polyvinyl alcohol aqueous solution; add sodium bentonite to an appropriate amount of deionized water and stir vigorously at 1800~2200 rpm for 1 h at room temperature to obtain a bentonite suspension; add the polyvinyl alcohol aqueous solution dropwise to the bentonite suspension and react for 2 h under heating to 60 ℃ and stirring conditions to obtain a polyvinyl alcohol pre-occupied bentonite suspension;

[0042] (2) Dissolve zinc acetate dihydrate and citric acid together in an appropriate amount of deionized water and stir at room temperature for 10 min to form a Zn-citric acid complex solution; then add it dropwise to a polyvinyl alcohol pre-occupied bentonite suspension under stirring, heat to 60 °C, and react under stirring for 1 h to achieve slow release and uniform distribution of the zinc complex; in the reaction system, the mass ratio of polyvinyl alcohol, bentonite, zinc acetate dihydrate and citric acid is 2~5:10:2~4:2~6 (based on bentonite as the reference).

[0043] (3) Dissolve ammonium bicarbonate in an appropriate amount of deionized water to obtain an ammonium bicarbonate aqueous solution. Under vigorous stirring at 1000-1500 rpm, continue to add the ammonium bicarbonate aqueous solution dropwise to the reaction system of step (2) until the pH of the reaction system gradually rises to 6.5-7.5; then let it stand at room temperature for 12-24 h; during this process, the slowly released Zn... 2+ Gradually hydrolyzed to generate Zn(OH)2, the reaction system gradually thickens to achieve gelation, and finally forms a solid block wet gel;

[0044] (4) The wet gel was dried at 80 °C for 24 h, then crushed; it was then placed in a muffle furnace and heated to 350 °C at a rate of 2 °C / min, and held at that temperature for 2 h for calcination; then cooled to room temperature with the furnace to obtain nano-zinc oxide-bentonite composite particles. Figure 1 The composite particle SEM image shows that zinc oxide particles are uniformly dispersed on the surface and between layers of bentonite.

[0045] 2. Nanocomposite antibacterial and deodorizing cat litter products

[0046] Based on the nano zinc oxide-bentonite composite particles prepared by the above method, the present invention further provides a nano composite antibacterial and deodorizing cat litter, comprising the following raw materials in parts by weight: 65-90 parts of main substrate, 20-40 parts of functional components, 5-15 parts of agglomerating material, 6-10 parts of binder, 1-5 parts of thickener, and 0-3 parts of additives.

[0047] The main substrate is one or more of cassava starch, soybean fiber, corn cob, and bentonite; the functional component is nano-zinc oxide-bentonite composite particles prepared by the aforementioned method; the agglomerating material is one or more of bentonite, corn starch, and potato starch; the binder is one or more of corn starch, guar gum, and maltodextrin; the thickener is one or more of bentonite, cassava starch, and lignocellulose; and the additives are one or more of potassium sorbate, citric acid, food coloring, and plant essential oils.

[0048] 3. Preparation method of nanocomposite antibacterial and deodorizing cat litter

[0049] The preparation of the above-mentioned nanocomposite antibacterial and deodorizing cat litter includes the following steps:

[0050] (1) The functional component (nano zinc oxide-bentonite composite particles) is mixed with an appropriate amount of additives and an appropriate amount of binder, and then extruded and granulated using a mold. After being air-dried and cured at a temperature of 40~60 ℃, antibacterial and deodorizing functional particles are obtained. As an example, the functional particles are spherical particles with a diameter of 4 mm.

[0051] (2) Add the agglomerating material (for water absorption and agglomeration), thickener (for promoting rapid agglomeration), appropriate amount of additives and the remaining binder to an appropriate amount of water to make a water-soluble adhesive; after crushing and sieving the main substrate, add it to the water-soluble adhesive and stir to mix; after extruding and granulating using a mold, dry it at a temperature of 60~80 ℃ to obtain a cat litter substrate with a moisture content of less than 10%; as an example, the cat litter substrate is a long cylindrical particle with a diameter of Φ2 mm × 20 mm.

[0052] Depending on the product formulation, additives can be selectively added to the cat litter substrate and / or functional granules as needed to change color (food coloring), adjust odor (plant essential oils), and provide preservative and antioxidant effects (potassium sorbate, citric acid). Adhesives are essential components for achieving tight bonding between the cat litter substrate and functional granules, as well as assisting in granulation and shaping. They should be added in partial amounts in steps (1) and (2).

[0053] (3) Mix the cat litter base material and functional particles evenly in a weight ratio of 85~70:15~30 to obtain nano-composite antibacterial and deodorizing cat litter.

[0054] Figure 2 The image showcases a cat litter product as an example. Based on the choice of raw material formulation and pelleting mold, the product pellets have an appearance of off-white, elongated strips, such as... Figure 2 As shown in (a). When 30 mL of water is added to this cat litter product, it can be absorbed instantly, as... Figure 2 As shown in (b); and finally achieves clumping, as shown in Figure (b). Figure 2 As shown in (c).

[0055] (4) In order to meet the sales demand of the product in the terminal market, bag or can containers can be used to repackage the nanocomposite antibacterial and deodorizing cat litter product.

[0056] II. Specific Implementation Examples and Comparative Examples

[0057] For the cat litter products in the following embodiments and comparative examples, performance tests were conducted using the following methods:

[0058] Deodorization rate, according to Appendix C of T / SDPIA 05-2022, was tested for the removal rate of 300 ppm ammonia at 1 h and 24 h. Antibacterial rate, according to WS / T 650-2019 and GB / T 36004-2018 ATP bioluminescence method, was tested for the antibacterial rate against bacteria (Candida albicans as an example) after 60 min of treatment. Agglomeration time and dust evaluation, according to the relevant methods in T / GIA 015-2023, were graded as <0.1% (very low), 0.1%~0.3% (low), 0.3%~0.5% (moderate), and >0.5% (high).

[0059] Example 1: A nanocomposite antibacterial and deodorizing tofu cat litter

[0060] (1) When preparing composite particles, adjust the parameters as follows: the mass ratio of polyvinyl alcohol, bentonite, zinc acetate dihydrate and citric acid is 2:10:3:4; the stirring speed for bentonite dispersion is 2000 rpm; the stirring speed before gelation is 1200 rpm; and the final pH of the reaction system is 7.0. The specific preparation process and other operating parameters shall be carried out in accordance with the contents described in the first part of the invention technical solution summary.

[0061] (2) Cat litter raw material formula (by function, by weight), a tofu cat litter: 75 parts of main base material (soy fiber), 30 parts of functional component (nano zinc oxide-bentonite composite particles), 15 parts of clumping material (corn starch), 8 parts of binder (guar gum), 5 parts of thickener (cassava starch) and 3 parts of auxiliary agent (2 parts of food coloring + 1 part of citric acid).

[0062] (3) When preparing cat litter, the composite particles are mixed evenly with pigment and half of the amount of guar gum (4 parts), sprayed with an appropriate amount of water to moisten, extruded and granulated, and then air-dried and cured at 50 ℃ to obtain spherical functional particles with a diameter of about 4 mm; corn starch, tapioca starch, the remaining 4 parts of guar gum and citric acid are made into a viscous water-soluble adhesive, mixed and stirred with soybean fiber until uniform, extruded and granulated, and dried at 70 ℃ to obtain a long strip of cat litter substrate; the cat litter substrate: functional particles = 80:20 are mixed evenly according to the weight ratio, and packaged in aluminum-plastic composite bags.

[0063] (4) Performance test: 95% deodorization rate in 1 h, 98% deodorization rate in 24 h; 95% antibacterial rate; clumping time less than 2 s; dust rate 0.08% (very low).

[0064] Example 2: A nanocomposite antibacterial and deodorizing plant-based cat litter

[0065] (1) When preparing composite particles, the parameters were adjusted as follows: the mass ratio of polyvinyl alcohol, bentonite, zinc acetate dihydrate and citric acid was 5:10:2:2; the stirring speed for bentonite dispersion was 1800 rpm; the stirring speed before gelation was 1000 rpm; and the final pH of the reaction system was 6.5. The preparation process was the same as in Example 1.

[0066] (2) Cat litter raw material formula, a plant-based cat litter: 65 parts of main base material (45 parts of corn cob + 20 parts of cassava starch), 40 parts of functional component (nano zinc oxide-bentonite composite particles), 10 parts of clumping material (potato starch), 10 parts of binder (maltodextrin), 2 parts of thickener (wood fiber) and 1.2 parts of auxiliary agent (1 part of plant essential oil + 0.2 parts of potassium sorbate).

[0067] (3) When preparing cat litter, all additives are added to the cat litter base material; the air-drying temperature is 40 ℃; the drying temperature is 60 ℃; the mixing ratio of cat litter base material to functional particles is 70:30. Other preparation processes are the same as in Example 1.

[0068] (4) Performance test: 91% deodorization rate in 1 h, 95% deodorization rate in 24 h; 93% antibacterial rate; clumping time less than 5 s; dust rate 0.08% (very low).

[0069] Example 3: A nanocomposite antibacterial and deodorizing mixed cat litter

[0070] (1) When preparing composite particles, the mass ratio of polyvinyl alcohol, bentonite, zinc acetate dihydrate and citric acid was adjusted to 4:10:4:6; the stirring speed for bentonite dispersion was 2200 rpm; the stirring speed before gelation was 1500 rpm; and the final pH of the reaction system was 7.5. The preparation process was the same as in Example 1.

[0071] (2) Cat litter raw material formula, a mixed cat litter: main base material (50 parts soybean fiber + 24 parts bentonite + 16 parts tapioca starch) totaling 90 parts, functional component (nano zinc oxide-bentonite composite particles) 20 parts, clumping material (bentonite) 5 parts, binder (corn starch) 6 parts, thickener (bentonite) 1 part, and auxiliary agent 0 parts.

[0072] (3) When preparing cat litter, the air-drying temperature is 60 ℃; the drying temperature is 80 ℃; and the mixing ratio of cat litter base material to functional particles is 85:15. Other preparation processes are the same as in Example 1.

[0073] (4) Performance test: 96% deodorization rate in 1 h, 98% deodorization rate in 24 h; 96% antibacterial rate; clumping time less than 2 s; dust rate 0.1% (low).

[0074] Comparative Example 1: Cat litter made by physically mixing nano zinc oxide and bentonite

[0075] (1) Preparation of functional components: Commercial nano zinc oxide powder was directly and physically mixed with bentonite for 2 h, and this physically mixed powder was used to replace the composite particles of the present invention.

[0076] (2) Cat litter raw material formula, the functional component is adjusted to 3 parts of commercial nano zinc oxide powder + 27 parts of bentonite, totaling 30 parts, and other raw materials are the same as in Example 1.

[0077] (3) The preparation process for cat litter is the same as in Example 1.

[0078] (4) Performance test: 1-hour deodorization rate 78%, 24-hour deodorization rate 83%; antibacterial rate 77%; clumping time less than 3 seconds; dust rate 1.2% (more than 1.2%), posing a dust safety hazard. Poor safety and performance degradation.

[0079] Comparative Example 2: Cat litter prepared by co-precipitation method using nano-zinc oxide-bentonite composite particles

[0080] (1) Preparation of functional components: ZnO-bentonite composite was prepared by the classic in-situ precipitation method (reference ACSOmega 2024, 9(2), 2783-2794).

[0081] (2) Cat litter raw material formula: the functional component is adjusted to 30 parts of composite particles prepared by co-precipitation method, and other raw materials are the same as in Example 1.

[0082] (3) The preparation process for cat litter is the same as in Example 1.

[0083] (4) Performance test: 87% deodorization rate in 1 h, 91% deodorization rate in 24 h; 90% antibacterial rate; clumping time less than 2 s; dust rate 0.3% (low). The classic composite process has the disadvantages of poor dispersibility and weak bonding.

[0084] Comparative Example 3: Commercially available mid-to-high-end antibacterial and deodorizing cat litter

[0085] Brand A's main ingredients are tofu sand, bentonite, and nano silver ions. It uses silver ions for sterilization and deodorization: 85% deodorization rate in 1 hour and 95% in 24 hours; antibacterial rate of 92%; clumping time of less than 2 seconds; and dust rate of 0.3% (low).

[0086] Brand B's main components are tofu sand and nano-mineral sand. It reduces ammonia production through nano-mineral sand antibacterial technology: 88% deodorization rate in 1 hour, 94% deodorization rate in 24 hours; antibacterial rate of 87%; clumping time of less than 3 seconds; dust rate of 0.4% (moderate).

[0087] Brand C's main ingredients are tofu sand and deodorizing beads. It deodorizes by neutralizing the acid and alkali with baking soda: 87% deodorization rate in 1 hour and 97% in 24 hours; antibacterial rate of 45%; clumping time of less than 3 seconds; and dust rate of 0.2% (low).

[0088] The performance test results of the cat litter products in each embodiment and comparative example are summarized in Table 1:

[0089] Table 1 Performance Test Results of Cat Litter Products

[0090]

[0091] The test data shows that the cat litter product provided by this invention outperforms physical mixing, traditional co-precipitation processes, and other commercially available products in terms of deodorization efficiency, antibacterial performance, clumping time, and dust control. The composite particles prepared by the "two-component synergistic competitive adsorption" sol-gel method overcome the core challenges of nanoparticle dispersion and safety, enabling the cat litter product to achieve efficient deodorization and antibacterial properties while also ensuring rapid clumping, low dust, and high safety, thus possessing significant industrial application value.

[0092] The above description is merely an exemplary case of the present invention and is not intended to limit it. Any obvious modifications or simple variations made by those skilled in the art without departing from the core idea of ​​the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing nano-zinc oxide-bentonite composite particles, characterized in that, Includes the following steps: (1) Add polyvinyl alcohol aqueous solution dropwise to bentonite suspension and react under heating and stirring conditions to obtain polyvinyl alcohol pre-occupied bentonite suspension; (2) Dissolve zinc acetate dihydrate and citric acid together in deionized water and stir at room temperature to form a Zn-citric acid complex solution; then add it dropwise to a polyvinyl alcohol pre-occupied bentonite suspension under stirring conditions, and react under heating and stirring conditions to achieve slow release and uniform distribution of zinc complex. (3) Under vigorous stirring, continue to add ammonium bicarbonate aqueous solution to the reaction system of step (2) until the pH value rises slowly to 6.5~7.5; then let it stand at room temperature, and the slowly released Zn 2+ Gradually hydrolyzed to generate Zn(OH)2, the reaction system gradually thickens to achieve gelation, and finally forms a solid block wet gel; (4) After drying and crushing the wet gel, it is placed in a muffle furnace for calcination and cooled to obtain nano zinc oxide-bentonite composite particles.

2. The method according to claim 1, characterized in that, In the raw materials used in steps (1) and (2), the mass ratio of polyvinyl alcohol, bentonite, zinc acetate dihydrate and citric acid is 2~5:10:2~4:2~6.

3. The method according to claim 1, characterized in that, Polyvinyl alcohol was added to an appropriate amount of deionized water and stirred in a 90 ℃ water bath until completely dissolved to obtain a polyvinyl alcohol aqueous solution; sodium bentonite was added to an appropriate amount of deionized water and stirred vigorously at 1800~2200 rpm for 1 h at room temperature to obtain a bentonite suspension; zinc acetate dihydrate and citric acid were added to an appropriate amount of deionized water and dissolved, and stirred at room temperature for 10 min to form a Zn-citric acid complex solution. Ammonium bicarbonate was dissolved in an appropriate amount of deionized water to obtain an aqueous solution of ammonium bicarbonate.

4. The method according to claim 1, characterized in that, In step (1), the temperature is raised to 60 °C for reaction and the reaction time is 2 h; in step (2), the temperature is raised to 60 °C for reaction and the reaction time is 1 h; in step (3), the vigorous stirring condition refers to stirring at a speed of 1000~1500 rpm and standing time is 12~24 h; in step (4), the drying temperature is 80 °C and the time is 24 h; during calcination, the temperature is raised to 350 °C at a rate of 2 °C / min, held for 2 h, and then cooled to room temperature with the furnace.

5. A nanocomposite antibacterial and deodorizing cat litter, comprising the following raw materials in parts by weight: 65-90 parts of main substrate, 20-40 parts of functional components, 5-15 parts of clumping material, 6-10 parts of adhesive, 1-5 parts of thickener, and 0-3 parts of additives; The main substrate is one or more of cassava starch, soybean fiber, corn cob, and bentonite; the functional component refers to nano-zinc oxide-bentonite composite particles prepared by the method described in any one of claims 1 to 4; the agglomerating material is one or more of bentonite, corn starch, and potato starch; the binder is one or more of corn starch, guar gum, and maltodextrin; the thickener is one or more of bentonite, cassava starch, and lignocellulose; and the additives are one or more of potassium sorbate, citric acid, food coloring, and plant essential oils.

6. The preparation method of the nanocomposite antibacterial and deodorizing cat litter according to claim 5, characterized in that, Includes the following steps: (1) The functional components are mixed with an appropriate amount of additives and an appropriate amount of binder, and after granulation and air drying, antibacterial and deodorizing functional particles are obtained. (2) Add the agglomerating material, thickener, appropriate amount of additives and the remaining adhesive to an appropriate amount of water to make a water-soluble adhesive; after crushing and sieving the main substrate, add it to the water-soluble adhesive and stir to mix; after granulation and drying, obtain the cat litter substrate; (3) Mix the cat litter base material and functional particles evenly to obtain a nano-composite antibacterial and deodorizing cat litter product.

7. The method according to claim 6, characterized in that, In step (1), granulation refers to extruding granules using a mold, and the air-drying and curing temperature is 40~60 ℃; in step (2), granulation refers to extruding granules using a mold, and the drying temperature is 60~80 ℃, and the moisture content of the cat litter substrate is less than 10%; in step (3), the cat litter substrate and functional particles are mixed in a weight ratio of 85~70:15~30.

8. The method according to claim 6, characterized in that, According to the product formulation design, additives are added to the cat litter substrate and / or functional granules; The adhesive is an essential component of the cat litter substrate and functional granules, and should be added in portions in steps (1) and (2) respectively.

9. The method according to claim 6, characterized in that, The functional particles are spherical particles with a diameter of 4 mm; the cat litter substrate is a long cylindrical particle with a diameter of 2 mm × 20 mm.

10. The method according to claim 6, characterized in that, Further includes: The nanocomposite antibacterial and deodorizing cat litter product is packaged using bag-shaped or can-shaped containers.

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