Antibacterial high-capacity ammonia adsorption modified zeolite as well as preparation method and application thereof

Abstract

The invention provides a preparation method and application of antibacterial high-capacity ammonia adsorption modified zeolite, and the antibacterial high-capacity ammonia adsorption modified zeolite is prepared by taking zeolite as a raw material, carrying out acid pickling, sodium modification, drying and roasting to obtain an intermediate product, then loading antibacterial ions, and then carrying out surface silanization and low-temperature roasting to obtain the antibacterial high-capacity ammonia adsorption modified zeolite. Zeolite impurities are removed through acid pickling and chambering is carried out, the cation exchange capacity is improved through sodium modification, antibacterial performance is achieved through antibacterial ion loading, the ammonia gas adsorption selectivity and stability are enhanced through surface silanization, and the adsorption capacity of the prepared modified zeolite is larger than or equal to 3.5 mmol / g under the conditions that the temperature is 25 DEG C and the ammonia gas is 200 ppm. The antibacterial rate on escherichia coli and staphylococcus aureus is larger than or equal to 90%, the antibacterial agent can be used for preparing pet padding, refrigerator deodorization bags and wet garbage deodorization particles, the process is simple and easy to industrialize, and efficient deodorization and safe antibiosis are both considered.

Description

Technical Field

[0001] This invention relates to the field of environmentally friendly functional materials technology, specifically to an antibacterial high-capacity ammonia adsorption modified zeolite, its preparation method, and its application. Background Technology

[0002] Ammonia is a frequently occurring and significantly harmful odorous pollutant in daily household life, pet care, and urban wet waste disposal. Its generation is closely related to the degradation of organic matter. Leftover food in household kitchens, the decomposition of urine and feces in pet bedding, and the putrefaction of kitchen waste in wet waste transfer stations and treatment plants all continuously release ammonia.

[0003] The dangers of ammonia extend beyond its strong, pungent odor; it poses a dual threat to human health and environmental hygiene. Physiologically, as an alkaline gas, ammonia directly irritates the respiratory tract mucosa, eye mucosa, and skin. Short-term exposure can cause discomfort such as coughing, sore throat, and tearing, while long-term exposure may lead to respiratory diseases such as chronic pharyngitis and bronchitis, particularly affecting the elderly, children, and those with allergies. Simultaneously, the humid, alkaline environment created by ammonia provides ideal conditions for the growth of pathogenic bacteria such as Escherichia coli and Staphylococcus aureus. Studies have shown that when ammonia concentrations exceed 20 ppm, the number of E. coli colonies on pet bedding surfaces can increase 3-5 times within 24 hours. These bacteria not only exacerbate odors by producing secondary malodorous substances like putrescine and cadaverine, but can also spread through contact, causing skin infections in pets or gastrointestinal discomfort in humans, creating a vicious cycle of "malodor - bacterial growth - secondary pollution."

[0004] Among materials for treating ammonia pollution, natural zeolite has become an important choice as a traditional adsorbent due to its unique crystal structure and physicochemical properties. The framework of zeolite is formed by silicon-oxygen tetrahedra (SiO4) and aluminum-oxygen tetrahedra (AlO4) linked by oxygen atoms. The natural pore sizes are mostly concentrated in the range of 0.3-1.0 nm, perfectly suited for the adsorption of ammonia molecules. Simultaneously, the Al³⁺ in the aluminum-oxygen tetrahedra... + Its electronegativity is lower than that of Si 4+ To allow the zeolite framework to carry localized negative charges, it is necessary to combine Na... + Ca² + The isocations maintain charge balance, a property that endows it with cation exchange capacity (CEC), allowing it to adsorb NH4 formed after the protonation of ammonia through ion exchange. + However, natural zeolite suffers from three major drawbacks in practical applications, severely limiting its deodorizing and antibacterial effects: First, its adsorption capacity is limited; the pores of natural zeolite are easily contaminated by amorphous SiO2, Fe2O3, and Ca²⁺ associated with the ore. + Mg² +Impurities such as NH4+ can clog the surface area, resulting in a specific surface area far below the requirements for highly efficient adsorption materials; simultaneously, their cation exchange capacity (CEC) is typically low for NH4+. + First, the exchange capacity is insufficient, resulting in generally low static adsorption capacity of natural zeolite for ammonia, making it difficult to meet the long-term deodorization needs (requiring continuous adsorption for more than 7 days) in household and pet settings. Second, it lacks antibacterial function. Although the porous structure of natural zeolite can adsorb ammonia, it also provides a hiding place for bacteria. Residual organic matter in the pores, such as proteins in pet bedding and carbohydrates in wet garbage, becomes a nutrient source for bacteria, turning the zeolite itself into a microbial breeding ground. This not only fails to inhibit the spread of pathogens but may also produce new odor substances due to bacterial metabolism, leading to the awkward situation of deodorizing but not inhibiting bacteria. Third, existing modification methods are simplistic and contradictory. To improve zeolite performance, existing technologies mostly adopt a single modification strategy: only acid washing, but this cannot impart antibacterial properties; only ion exchange loading of Zn² + Cu² + While antibacterial ions can achieve a certain antibacterial effect, they are easily dissolved in water, posing a safety risk of pets accidentally ingesting them or coming into contact with their skin.

[0005] In view of the problems existing in the prior art, how to provide a modified zeolite with high efficiency, long-lasting adsorption capacity, safe antibacterial properties, and simple processing is the problem that this invention urgently needs to solve. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a method for preparing a modified zeolite with high antibacterial capacity and ammonia adsorption. The method involves a multi-step synergistic modification process to prepare a modified zeolite with high efficiency, long-lasting adsorption capacity, safe antibacterial properties, and stable structure. The invention also provides the modified zeolite and its applications.

[0007] The technical solution of this invention: A high-capacity antibacterial ammonia adsorption modified zeolite includes the following steps: Acid washing: The zeolite and hydrochloric acid solution are mixed in a solid-liquid ratio and reacted at 60-70℃ for 1-2 hours, and then washed until neutral. Sodiumification: The acid-washed zeolite is mixed with sodium chloride solution and reacted at 65-75℃ for 1-2 hours. After washing and drying, the sodium-treated zeolite is calcined at 300-380℃ for 2-4 hours to obtain the intermediate product. Loading antibacterial ions: The obtained intermediate product is mixed with an antibacterial ion solution and reacted at 50-80℃ for 1-3 hours, followed by washing and drying; Surface silanization: Zeolite loaded with antibacterial ions is mixed with a silane complex solution and reacted at 75-85℃ for 1-2 hours; Low-temperature calcination: The silanized zeolite is calcined at 300-380℃ for 2-4 hours to obtain antibacterial high-capacity ammonia adsorption modified zeolite.

[0008] In some embodiments of the present invention, the solid-liquid ratio of the zeolite to the hydrochloric acid solution in the pickling step is 1 g: 5-8 mL; the concentration of the hydrochloric acid solution is 2-5 mol / L. A solid-liquid ratio of 1:5-8 ensures sufficient contact between the hydrochloric acid and the zeolite particles, while a concentration of 2-5 mol / L is sufficient to dissolve the Ca²⁺ within the pores. + Mg² + Impurities and amorphous SiO2 are removed to expand the pores, while avoiding excessive etching of the zeolite framework due to excessive concentration or liquid volume, thus balancing the pore expansion effect and structural stability.

[0009] In some embodiments of the present invention, the concentration of the sodium chloride solution in the sodicization step is 1-2 mol / L. A 1-2 mol / L NaCl solution can provide sufficient Na+. + It can efficiently replace the low-activity Fe³⁺ in the zeolite framework at 65-75℃. + Al³ + The presence of isocations significantly enhances the cation exchange capacity (CEC), laying the foundation for subsequent antibacterial ion loading and ammonia adsorption (via ion exchange); excessively high concentrations can easily lead to Na+ ionization. + Excessive occupation of sites leads to insufficient replacement, while insufficient occupation results in inadequate replacement.

[0010] In some embodiments of the present invention, the concentration of the antibacterial ion solution in the antibacterial ion loading step is 0.1-0.5 mol / L; the antibacterial ion solution is one or a mixture of zinc chloride, zinc sulfate, and copper sulfate. A concentration of 1-0.5 mol / L ensures the presence of antibacterial ions (Zn²⁺). + Cu² + Zn²⁺ is fully loaded onto the zeolite through ion exchange, while avoiding excessive concentration that could lead to ion aggregation. + Cu² + It is a broad-spectrum antibacterial agent that can disrupt bacterial cell membranes and enzyme systems. When used in combination, it can produce a synergistic antibacterial effect and enhance the inhibitory effect on Escherichia coli and Staphylococcus aureus.

[0011] In some embodiments of the present invention, the raw materials of the silane complex solution in the surface silanization step include aminosilane, lipophilic silane, complex organic acid solution, and organic solvent; the mass ratio of aminosilane to lipophilic silane is 1-5:1. Aminosilane (containing -NH2) can enhance the chemical adsorption of ammonia through hydrogen bonding and acid-base interactions, while lipophilic silane (such as long-chain alkylsilanes) can inhibit silane molecule aggregation and improve the dispersibility of the silane layer; the 1-5:1 ratio balances the functions of both, ensuring sufficient adsorption sites while avoiding excessive lipophilic chains that hinder ammonia contact, thus optimizing adsorption efficiency.

[0012] In some embodiments of the present invention, the aminosilane is at least one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; the lipophilic silane is selected from at least one of decanyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, and phenyltrimethoxysilane.

[0013] In some embodiments of the present invention, the total mass of the aminosilane and the lipophilic silane is 2-5% of the mass of the zeolite loaded with antibacterial ions, and the amount of the composite organic acid solution added is 5-15% of the total mass of the aminosilane and the lipophilic silane. 2-5% of the total silane mass can form a complete adsorption layer on the zeolite surface without clogging the pores; 5-15% of the composite organic acid can gently catalyze the hydrolysis of silane, promoting its uniform grafting; the organic solvent (anhydrous ethanol) ensures that the silane solution fully wets the zeolite, avoiding local agglomeration and ensuring the uniformity of silanization.

[0014] In some embodiments of the present invention, the composite organic acid solution uses anhydrous ethanol as a solvent and at least two hydroxycarboxylic acids selected from citric acid, tartaric acid, and malic acid as solutes. Hydroxycarboxylic acids (such as citric acid) are weak acids, which can catalyze the hydrolysis of silanes and avoid the destruction of zeolite structures by strong acids; the combination of at least two acids can synergistically improve catalytic efficiency.

[0015] The present invention discloses an antibacterial high-capacity ammonia adsorption modified zeolite, which is prepared by the preparation method of any one of claims 1-8, wherein the antibacterial high-capacity ammonia adsorption modified zeolite has an adsorption capacity of ≥3.5mmol / g under the conditions of 25℃ and 200ppm ammonia.

[0016] This invention relates to an application of a modified zeolite with high ammonia adsorption capacity for antibacterial purposes, characterized by its use in the preparation of pet bedding, refrigerator deodorizing bags, or wet waste deodorizing granules. These applications all require efficient removal of ammonia (deodorization) and inhibition of bacterial growth (antibacterial). The modified zeolite's "high adsorption capacity + ≥90% antibacterial rate" characteristics can specifically address the odor and hygiene issues in these applications, and the process is simple, easily industrialized, and suitable for large-scale application.

[0017] The antibacterial, high-capacity ammonia adsorption modified zeolite of this invention exhibits performance derived from a multi-process synergistic system encompassing physical adsorption, chemical action, and antibacterial protection. The acid washing stage dissolves Ca²⁺ within the pores. + Mg² + Impurities and amorphous SiO2 are etched to form hierarchical micropores, significantly increasing the specific surface area and providing channels for ammonia diffusion; during sodiumization, Na... + Replacing the low-activity cations in the zeolite framework increases the cation exchange capacity (CEC) and enhances the resistance to protonated ammonia (NH4+). +The ion exchange adsorption capacity of the zeolite is demonstrated. In the antibacterial ion loading stage, the antibacterial ions are fixed to the zeolite through ion exchange, providing active sites for subsequent antibacterial activity and facilitating ammonia adsorption through metal coordination. In the surface silanization stage, the -NH2 group of aminosilane forms hydrogen bonds and neutralizes acid and base with ammonia; the lipophilic silane inhibits silane aggregation; and the composite organic acid catalyzes silane hydrolysis, ensuring uniform grafting onto the zeolite surface and enhancing adsorption selectivity. Low-temperature calcination further strengthens the Si-O-Si covalent bonds, preventing the loss of active sites. Ultimately, an ammonia adsorption capacity of ≥3.5 mmol / g at 25℃ and 200 ppm is achieved, while also exhibiting antibacterial properties.

[0018] Beneficial effects: 1. Excellent synergistic performance: The modified zeolite has an ammonia adsorption capacity of ≥3.5 mmol / g, an antibacterial rate of ≥90%, and low antibacterial ion leaching, meeting the safety requirements for household and pet scenarios; 2. The process is easy to industrialize: each step uses conventional equipment (mixing tank, drying oven, muffle furnace), the parameters are mild (temperature ≤380℃, no high pressure), the raw material cost is low, and it is suitable for large-scale production; 3. Strong application adaptability: It can be directly processed into granules (suitable for pet bedding), powder (suitable for refrigerator deodorizing bags), or compounded with tofu matrix, with a wide range of applications. Detailed Implementation

[0019] The present invention will be described below with reference to specific implementation schemes. It should be noted that the experimental examples below are illustrative of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0020] Unless otherwise specified, all chemical reagents used in this invention are commercially available analytical grade, and the zeolite is 200-300 mesh clinoptilolite from Shandong.

[0021] Example 1 Acid washing: Take 100g of 200-mesh zeolite, mix it with 500mL of 2mol / L hydrochloric acid solution, stir and react at 60℃ for 2h, wash with deionized water until pH 6.5, and filter. Sodiumization: Acid-washed zeolite was mixed with 500 mL of 1 mol / L sodium chloride solution, stirred at 65 °C for 2 h, filtered, dried at 105 °C for 3 h, and then calcined at 300 °C for 4 h to obtain the intermediate product. Loading antibacterial ions: The intermediate product was mixed with 500 mL of antibacterial ion solution (0.2 mol / L ZnSO4 solution), the pH was adjusted to 5.0 with dilute HCl, the mixture was stirred at 50 °C for 3 h, filtered, and dried at 105 °C for 3 h. Surface silanization: Preparation of composite organic acid solution: Weigh 1g of citric acid and 1g of tartaric acid, dissolve them in 8g of anhydrous ethanol, and stir until completely dissolved to obtain composite organic acid solution; Preparation of silane complex solution: Weigh 2g of γ-aminopropyltriethoxysilane and 2g of dodecyltrimethoxysilane, then add 0.4g of the above complex organic acid solution, add 50mL of anhydrous ethanol, stir for 10min, then impregnate and uniformly coat 100g of zeolite loaded with antibacterial ions, and stir at 75℃ for 1h. Low-temperature calcination: Calcination at 300℃ for 4 hours yielded antibacterial high-capacity ammonia adsorption modified zeolite.

[0022] Example 2 Acid washing: Take 100g of 200-mesh zeolite, mix it with 800mL of 5mol / L hydrochloric acid solution, stir and react at 70℃ for 1h, wash until pH 6.8, and filter. Sodiumization: Mix with 800 mL of 2 mol / L sodium chloride solution, react at 75 °C for 1 h, filter, dry at 120 °C for 2 h, and calcine at 380 °C for 2 h to obtain the intermediate product; Loading antibacterial ions: Mix with 800 mL of antibacterial ion solution (0.1 mol / L CuSO4 solution), adjust pH to 7.0 with dilute NaOH, react at 80℃ for 1 h, and then dry. Surface silanization: Preparation of composite organic acid solution: Weigh 1.5g of malic acid and 0.5g of citric acid, dissolve them in 8g of anhydrous ethanol, and stir until completely dissolved to obtain composite organic acid solution; Preparation of silane complex solution: Weigh 5g of γ-aminopropyltriethoxysilane and 1g of decanyltrimethoxysilane, then add 0.9g of the above complex organic acid solution, add 50mL of anhydrous ethanol, stir for 10min, then impregnate and uniformly coat 100g of zeolite loaded with antibacterial ions, and stir at 80℃ for 1h. Low-temperature calcination: Calcination at 380℃ for 2 hours yielded antibacterial high-capacity ammonia adsorption modified zeolite.

[0023] Example 3 Acid washing: Take 100g of 300-mesh zeolite, mix it with 600mL of 3mol / L hydrochloric acid solution, react at 65℃ for 1.5h, and wash until pH 7; Sodiumization: 600 mL of 1.5 mol / L sodium chloride, react at 70 °C for 1.5 h, dry at 110 °C for 2.5 h, and calcine at 350 °C for 3 h; Loading antibacterial ions: 600 mL of antibacterial ion solution (0.2 mol / L ZnSO4 solution + 0.1 mol / L CuSO4 solution), pH 6.0, reacted at 65℃ for 2 h, then dried; Surface silanization: Preparation of composite organic acid solution: Weigh 0.8g of citric acid, 0.8g of tartaric acid and 0.4g of malic acid, dissolve them in 8g of anhydrous ethanol, and stir until completely dissolved to obtain composite organic acid solution; Preparation of silane complex solution: Weigh 3g of γ-aminopropyltrimethoxysilane and 1g of phenyltrimethoxysilane, then add 0.6g of the above complex organic acid solution, add 50mL of anhydrous ethanol, stir for 10min, then impregnate and uniformly coat 100g of zeolite loaded with antibacterial ions, and stir at 75℃ for 1h. Low-temperature calcination: Antibacterial high-capacity ammonia adsorption modified zeolite was obtained by calcination at 350℃ for 3 hours.

[0024] Example 4 Acid washing: Take 100g of 200-mesh zeolite, mix it with 500mL of 2mol / L hydrochloric acid solution, stir and react at 60℃ for 2h, wash with deionized water until pH 6.5, and filter. Sodiumization: Acid-washed zeolite was mixed with 500 mL of 1 mol / L sodium chloride solution, stirred at 65 °C for 2 h, filtered, dried at 105 °C for 3 h, and then calcined at 300 °C for 4 h to obtain the intermediate product. Loading antibacterial ions: The intermediate product was mixed with 500 mL of antibacterial ion solution (0.2 mol / L ZnSO4 solution), the pH was adjusted to 5.0 with dilute HCl, the mixture was stirred at 50 °C for 3 h, filtered, and dried at 105 °C for 3 h. Surface silanization: Preparation of composite organic acid solution: Weigh 1g of citric acid and 1g of tartaric acid, dissolve them in 8g of anhydrous ethanol, and stir until completely dissolved to obtain composite organic acid solution; Preparation of silane complex solution: Weigh 4g of γ-aminopropyltriethoxysilane, then add 0.4g of the above complex organic acid solution, add 50mL of anhydrous ethanol, stir for 10min, then impregnate and uniformly coat 100g of zeolite loaded with antibacterial ions, and stir at 75℃ for 1h. Low-temperature calcination: Calcination at 300℃ for 4 hours yielded antibacterial high-capacity ammonia adsorption modified zeolite.

[0025] Comparative Example 1 Acid washing: Take 100g of 200-mesh zeolite, mix it with 500mL of 2mol / L hydrochloric acid solution, stir and react at 60℃ for 2h, wash with deionized water until pH 6.5, and filter. Sodiumization: Acid-washed zeolite was mixed with 500 mL of 1 mol / L sodium chloride solution, stirred at 65 °C for 2 h, filtered, dried at 105 °C for 3 h, and then calcined at 300 °C for 4 h to obtain the intermediate product. Loading antibacterial ions: The intermediate product was mixed with 500 mL of antibacterial ion solution (0.2 mol / L ZnSO4 solution), the pH was adjusted to 5.0 with dilute HCl, the mixture was stirred at 50 °C for 3 h, filtered, and dried at 105 °C for 3 h. Surface silanization: Preparation of silane complex solution: Weigh 2g of γ-aminopropyltriethoxysilane and 2g of dodecyltrimethoxysilane, add 50mL of anhydrous ethanol, stir for 10min, then impregnate and uniformly coat 100g of zeolite loaded with antibacterial ions, and stir at 75℃ for 1h. Low-temperature calcination: Calcination at 300℃ for 4 hours yielded antibacterial high-capacity ammonia adsorption modified zeolite.

[0026] Comparative Example 2 Acid washing: Take 100g of 200-mesh zeolite, mix it with 500mL of 2mol / L hydrochloric acid solution, stir and react at 60℃ for 2h, wash with deionized water until pH 6.5, and filter. Sodiumization: Acid-washed zeolite was mixed with 500 mL of 1 mol / L sodium chloride solution, stirred at 65 °C for 2 h, filtered, dried at 105 °C for 3 h, and then calcined at 300 °C for 4 h to obtain the intermediate product. Surface silanization: Preparation of composite organic acid solution: Weigh 1g of citric acid and 1g of tartaric acid, dissolve them in 8g of anhydrous ethanol, stir until completely dissolved, and obtain a composite organic acid solution with a concentration of 20%. Preparation of silane complex solution: Weigh 2g of γ-aminopropyltriethoxysilane and 2g of dodecyltrimethoxysilane, then add 0.4g of the above complex organic acid solution, add 50mL of anhydrous ethanol, stir for 10min, then impregnate and uniformly coat 100g of intermediate product, and stir at 75℃ for 1h. Low-temperature calcination: Calcination at 300℃ for 4 hours yielded antibacterial high-capacity ammonia adsorption modified zeolite.

[0027] Comparative Example 3 Acid washing: Take 100g of 200-mesh zeolite, mix it with 500mL of 2mol / L hydrochloric acid solution, stir and react at 60℃ for 2h, wash with deionized water until pH 6.5, and filter. Sodiumization: Acid-washed zeolite was mixed with 500 mL of 1 mol / L sodium chloride solution, stirred at 65 °C for 2 h, filtered, dried at 105 °C for 3 h, and then calcined at 300 °C for 4 h to obtain the intermediate product. Loading antibacterial ions: The intermediate product was mixed with 500 mL of antibacterial ion solution (0.2 mol / L ZnSO4 solution), the pH was adjusted to 5.0 with dilute HCl, the mixture was stirred at 50 °C for 3 h, filtered, and dried at 105 °C for 3 h. Low-temperature calcination: Calcination at 300℃ for 4 hours yielded antibacterial high-capacity ammonia adsorption modified zeolite.

[0028] Performance testing: 1. Ammonia adsorption capacity test: The static adsorption method was adopted, referring to GB / T 7702.7-2008 "Determination of Adsorption Performance of Activated Carbon - Part 7: Ammonia Adsorption", and the specific steps are as follows: Take 0.5g of the modified zeolite samples prepared in each example and comparative example, and place them in a sealed adsorption bottle in a constant temperature water bath at 25℃. Ammonia standard gas of 200 ppm was introduced, and after equilibration for 24 hours, the concentration of residual ammonia in the adsorption bottle was detected by gas chromatograph (model: GC-2014). The adsorption capacity (mmol / g) is calculated using the formula: Adsorption capacity (mmol / g) = (Initial concentration - Equilibrium concentration) × Adsorption bottle volume / (Sample mass × Gas molar volume) (Gas molar volume is taken as 24.45 L / mol, 25℃ standard state); The ammonia adsorption capacity on day 1 (initial) and day 7 is measured respectively, and the adsorption capacity decay rate (%) on day 7 is calculated as: (Adsorption capacity on day 1 - Adsorption capacity on day 7) / Adsorption capacity on day 1 × 100%. The lower the decay rate, the stronger the continuous adsorption capacity.

[0029] 2. Antibacterial performance test: Referring to the "Test Method for Antibacterial Performance of Nano-Inorganic Materials" (GB / T 21510-2008), the inhibition zone method combined with the colony counting method was used. The test subjects were Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC6538). The steps are as follows: Preparation 10 6 Take 0.1 mL of the CFU / mL bacterial suspension and spread it evenly on nutrient agar medium; place 0.2 g of modified zeolite sample in the center of the medium and incubate at 37℃ for 24 h, then measure the diameter of the inhibition zone; at the same time, mix the sample and bacterial suspension at a ratio of 1:10 (g:mL), shake for 2 h, then dilute and spread, count the surviving colonies, and calculate the antibacterial rate (%) according to the formula: antibacterial rate (%) = (number of colonies in the blank group - number of colonies in the sample group) / number of colonies in the blank group × 100%.

[0030] 3. Antibacterial ion leaching test: Referencing GB / T 5750.6-2023 Standard Examination Methods for Drinking Water – Part 6: Metals and Metalloids, the test was performed using an inductively coupled plasma mass spectrometer (ICP-MS, model: Agilent 7800). Take 1g of modified zeolite sample, add 10mL of deionized water, shake at 25℃ for 24h; after centrifugation and filtration, detect the Zn²⁺ content in the filtrate. + / Cu² + Concentration refers to the amount of antibacterial ions dissolved over 24 hours.

[0031] Table 1: Performance Test Results

[0032] The test results show that the antibacterial high-capacity ammonia adsorption modified zeolite of this invention has an adsorption capacity ≥3.5 mmol / g under 25℃ and 200 ppm ammonia conditions, a low 7-day decay rate, and long-lasting adsorption capacity. It exhibits an antibacterial rate ≥90% against Escherichia coli and Staphylococcus aureus, stable structure, and long-lasting antibacterial and deodorizing effects. Specifically, comparing Experimental Example 1 with Example 4 shows that using only aminosilane without lipophilic silane leads to easy aggregation of the silane layer due to water molecule adsorption, resulting in a higher 7-day decay rate. This indicates that the combination of aminosilane and lipophilic silane can enhance the anti-agglomeration ability of the silane layer and improve its long-lasting effect. Comparing Experimental Example 1 with Comparative Example 1 shows that the silane... Incomplete hydrolysis resulted in a loose bond between the silane layer and zeolite, leading to partial silane detachment after cyclic desorption. This resulted in low retention and high attenuation rates, demonstrating the crucial role of composite organic acids in enhancing the stability of silane grafting. A comparison between Experimental Example 1 and Comparative Example 2 revealed that without antibacterial ion inhibition, microorganisms proliferated within the pores during prolonged adsorption, clogging adsorption sites. This resulted in a high attenuation rate after 7 days and a low antibacterial rate, failing to meet the dual requirements of long-term antibacterial and odor control. A comparison between Experimental Example 1 and Comparative Example 3 showed that without silane layer protection, ammonia readily and irreversibly adsorbed onto the zeolite framework, causing pore blockage. Furthermore, continuous dissolution of antibacterial ions increased the attenuation rate after 7 days, rendering the experiment unsuitable for long-term use.

[0033] This invention can also be demonstrated through various other experimental examples. Without departing from the spirit and essence of this invention, those skilled in the art can make various corresponding changes and modifications according to this invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A method for preparing antibacterial, high-capacity ammonia adsorption modified zeolite, characterized in that, Includes the following steps: Acid washing: The zeolite and hydrochloric acid solution are mixed in a solid-liquid ratio and reacted at 60-70℃ for 1-2 hours, and then washed until neutral. Sodiumification: The acid-washed zeolite is mixed with sodium chloride solution and reacted at 65-75℃ for 1-2 hours. After washing and drying, the sodium-treated zeolite is calcined at 300-380℃ for 2-4 hours to obtain the intermediate product. Loading antibacterial ions: The obtained intermediate product is mixed with an antibacterial ion solution and reacted at 50-80℃ for 1-3 hours, followed by washing and drying; Surface silanization: Zeolite loaded with antibacterial ions is mixed with a silane complex solution and reacted at 75-85℃ for 1-2 hours; Low-temperature calcination: The silanized zeolite is calcined at 300-380℃ for 2-4 h to obtain antibacterial high-capacity ammonia adsorption modified zeolite.

2. The preparation method of the antibacterial high-capacity ammonia adsorption modified zeolite according to claim 1, characterized in that, In the pickling step, the solid-liquid ratio of the zeolite to the hydrochloric acid solution is 1g:5-8mL; the concentration of the hydrochloric acid solution is 2-5mol / L.

3. The preparation method of the antibacterial high-capacity ammonia adsorption modified zeolite according to claim 1, characterized in that, The concentration of the sodium chloride solution in the sodiumization step is 1-2 mol / L.

4. The preparation method of the antibacterial high-capacity ammonia adsorption modified zeolite according to claim 1, characterized in that, The concentration of the antibacterial ion solution in the antibacterial ion loading step is 0.1-0.5 mol / L; the antibacterial ion solution is one or a mixture of zinc chloride, zinc sulfate, and copper sulfate.

5. The preparation method of the antibacterial high-capacity ammonia adsorption modified zeolite according to claim 1, characterized in that, The raw materials for the silane complex solution in the surface silanization step include aminosilane, lipophilic silane, complex organic acid solution, and organic solvent; the mass ratio of aminosilane to lipophilic silane is 1-5:

1.

6. The preparation method of the antibacterial high-capacity ammonia adsorption modified zeolite according to claim 1, characterized in that, The aminosilane is at least one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; the lipophilic silane is selected from at least one of decanyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, and phenyltrimethoxysilane.

7. The preparation method of the antibacterial high-capacity ammonia adsorption modified zeolite according to claim 1, characterized in that, The total mass of the aminosilane and lipophilic silane is 2-5% of the mass of the zeolite loaded with antibacterial ions, and the amount of the composite organic acid solution added is 5-15% of the total mass of the aminosilane and lipophilic silane.

8. The preparation method of the antibacterial high-capacity ammonia adsorption modified zeolite according to claim 1, characterized in that, The composite organic acid solution uses anhydrous ethanol as a solvent and at least two hydroxycarboxylic acids selected from citric acid, tartaric acid, and malic acid as solutes.

9. A type of antibacterial, high-capacity ammonia adsorption modified zeolite, characterized in that, The antibacterial high-capacity ammonia adsorption modified zeolite prepared by any one of claims 1-8 has an adsorption capacity ≥3.5 mmol / g under 25℃ and 200 ppm ammonia conditions.

10. The application of the antibacterial high-capacity ammonia adsorption modified zeolite according to claim 9, characterized in that, Used to prepare pet bedding, refrigerator deodorizing bags, or wet waste deodorizing granules.

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