A long-lasting, controllable-release antibacterial and deodorizing material for water treatment and its preparation method.

Abstract

This invention provides a long-lasting, controllable-release antibacterial and deodorizing material for water treatment and its preparation method, belonging to the technical field of water treatment materials. The method includes the following steps: immersing pretreated rice husk material in a magnesium acetate precursor solution, allowing it to stand, filtering, calcining, cooling, grinding, and drying to obtain a MgO / SiO2 composite porous material; adding polydopamine-calcium carbonate microspheres to a cinnamaldehyde / rosemary extract ethanol solution, stirring in the dark, centrifuging, collecting the precipitate, washing, and freeze-drying to obtain composite microspheres; adding the MgO / SiO2 composite porous material to deionized water, ultrasonicating, adding the composite microspheres, adjusting the pH to acidic, continuously stirring, vacuum filtering, washing, and freeze-drying to obtain the antibacterial and deodorizing material. This invention can achieve long-lasting antibacterial, bactericidal, and deodorizing effects during water treatment.

Description

Technical Field

[0001] This invention relates to the field of water treatment materials technology, specifically to a long-lasting, controllable-release antibacterial and deodorizing material for water treatment and its preparation method. Background Technology

[0002] While household water purifiers, water dispensers, and water storage tanks ensure drinking water safety, their internal damp and nutrient-rich environments can also become breeding grounds for microorganisms. The proliferation of bacteria, mold, and other microorganisms not only leads to secondary water pollution, directly threatening consumer health, but the hydrogen sulfide, ammonia, and other odor-causing substances produced during their metabolism also severely affect the taste and smell of the water, resulting in the so-called "stinky water" problem. Therefore, developing a household water treatment material that can effectively and safely inhibit microbial growth and eliminate odors is of paramount practical importance.

[0003] Currently, antibacterial and deodorizing materials used in water treatment can be mainly divided into the following types. First, there are release-type inorganic antibacterial agents (represented by silver-based materials). These materials achieve antibacterial effects by slowly releasing silver ions to destroy bacterial cell membranes. However, silver, as a precious metal, has a high material cost, making it unsuitable for large-scale application in household products. Furthermore, their primary function is antibacterial, with limited adsorption and decomposition capabilities for organic odor molecules, resulting in poor deodorization. Second, there are oxidizing antibacterial agents (such as chlorine preparations, ozone, and photocatalytic materials). These primarily destroy microbial structures or decompose odor molecules through strong oxidation. However, chlorine preparations easily react with organic matter in water to produce disinfection byproducts with carcinogenic, mutagenic, and teratogenic effects, such as trihalomethanes, which seriously threaten health. Ozone is unstable and cannot achieve long-lasting residual disinfection. Additionally, photocatalytic materials, represented by titanium dioxide, require ultraviolet light excitation and are almost ineffective in low-light or dark environments such as inside household water storage devices, limiting their application scenarios.

[0004] In contrast, some natural plant extracts are ideal "green" alternatives due to their natural antibacterial and aromatic properties. However, most plant extracts are highly hydrophobic and difficult to apply directly to aqueous systems. In addition, they generally have a certain degree of volatility and cannot achieve long-lasting effects, which is the biggest bottleneck restricting their application. Summary of the Invention

[0005] In view of this, the present invention provides a long-lasting, controllable release antibacterial and deodorizing material for water treatment and its preparation method, which can achieve long-lasting antibacterial, bactericidal and deodorizing effects during water treatment.

[0006] To achieve the above objectives, the present invention provides a method for preparing a long-lasting, controllable-release antibacterial and deodorizing material for water treatment, comprising the following steps:

[0007] S1. The pretreated rice husk material is immersed in a magnesium acetate precursor solution, allowed to stand, filtered, calcined, cooled, ground, and dried to obtain MgO / SiO2 composite porous material.

[0008] S2. Add polydopamine-calcium carbonate microspheres to cinnamaldehyde / rosemary extract ethanol solution, stir in the dark, centrifuge, collect the precipitate, wash, freeze dry, and obtain composite microspheres;

[0009] S3. Add the MgO / SiO2 composite porous material to deionized water, sonicate, add composite microspheres, adjust the pH to acidic, stir continuously, vacuum filter, wash, and freeze dry to obtain the antibacterial and deodorizing material.

[0010] This invention utilizes rice husk as a biological template and magnesium acetate as a magnesium-based precursor. During calcination, silicon in the rice husk is converted into SiO2, forming a binary oxide. This replicates the inherent macroporous structure of the rice husk template, resulting in a MgO / SiO2 composite porous material. Acid washing removes most metallic impurities and some hemicellulose, while retaining the rigid framework and porous structure of amorphous silica in the rice husk. Acid washing and subsequent calcination impart multi-level pores to the MgO / SiO2 composite porous material, resulting in a high specific surface area and promoting the generation of active oxygen. Furthermore, the introduction of MgO gives the surface of the MgO / SiO2 composite porous material a positive charge, which is more conducive to the electrostatic adsorption of anionic bacterial cells and pollutants, further enhancing the overall antibacterial effect of the MgO / SiO2 composite porous material.

[0011] This invention uses polydopamine-calcium carbonate microspheres as a carrier to encapsulate cinnamaldehyde / rosemary extract to prepare composite microspheres, achieving long-lasting antibacterial and deodorizing capabilities. The cinnamaldehyde and rosemary extract directly inhibit odor-producing microorganisms, eliminating odor at its source. In alkaline or neutral environments, the cinnamaldehyde and rosemary extract loaded inside diffuse into the external environment through the pores of the polydopamine layer, releasing slowly to achieve long-lasting release. During the growth and metabolism of numerous bacteria, the production of acidic substances causes a decrease in the local microenvironment pH. Under acidic conditions, the calcium carbonate inside the polydopamine-calcium carbonate microspheres partially dissolves, accelerating the release of cinnamaldehyde and rosemary extract and enhancing the antibacterial and bactericidal effect. In other words, the polydopamine-calcium carbonate microspheres can achieve long-lasting and controllable release of the internal cinnamaldehyde and rosemary extract.

[0012] Meanwhile, this invention uses a MgO / SiO2 composite porous material to support composite microspheres. The high specific surface area of ​​the MgO / SiO2 composite porous material allows the composite microspheres to enter or adhere to the inside and outside of the pores through physical adsorption. The MgO / SiO2 composite porous material achieves physical adsorption of pollutants and anionic bacterial cells through its multi-pitted nature; MgO itself provides long-lasting antibacterial properties and photocatalytic activity to achieve antibacterial performance; and the composite microspheres achieve long-lasting and controllable release of internal antibacterial components through pH response control. Through multiple synergistic mechanisms, the material prepared by this invention has excellent inhibitory and removal effects on bacteria, mold, and the resulting odors in water.

[0013] Optionally, the pretreated rice husk material is obtained by placing 70-80 parts by weight of rice husk into 800 parts by volume of a 5% hydrochloric acid solution, vacuum soaking at 10-15°C for 18-24 hours, filtering, soaking in deionized water for 10-12 hours, filtering and drying.

[0014] This invention uses vacuum soaking during the treatment of rice husk acid to improve the penetration efficiency of hydrochloric acid solution, increase the uniformity of the reaction, and reduce the influence of impurities, thereby providing a good reaction basis for subsequent magnesium salt deposition and high-temperature calcination reactions.

[0015] Optionally, the magnesium acetate precursor solution is obtained by adding 30-40 parts by mass of magnesium acetate to 700 parts by volume of an aqueous ethanol solution and stirring magnetically for 5 minutes; the volume ratio of ethanol to water in the aqueous ethanol solution is 1:1.

[0016] Optionally, the polydopamine-calcium carbonate microspheres are prepared by dissolving 4-5 parts by weight of gum arabic in 100 parts by volume of deionized water, magnetically stirring for 5-10 minutes, then adding 1200 parts by volume of deionized water, heating to 40°C, adding 20-25 parts by weight of calcium chloride, stirring continuously for 10-15 minutes, then adding 20-22 parts by weight of sodium carbonate, maintaining stirring at 40°C for 3-5 hours, centrifuging at 10000 rpm for 10-15 minutes, collecting the precipitate, and using deionized water... Resuspend the precipitate in water, sonicate for 20-30 min, then centrifuge at 10000 rpm for 10-15 min, collect the precipitate, add it to 1500 volumes of 0.01 mol / L Tris-HCl buffer, stir magnetically for 5-10 min, add 0.2-0.3 parts by weight of dopamine hydrochloride, stir in the dark for 10-12 h, centrifuge at 10000 rpm for 10-15 min, wash 2-5 times with deionized water, and freeze-dry to obtain the final product.

[0017] This invention uses calcium chloride and sodium carbonate as inorganic precursors and gum arabic as a biotemplate and crystal growth regulator to grow calcium carbonate crystal particles. The long-chain molecules of gum arabic adsorb onto the surface of the nascent CaCO3 nanoparticles, preventing excessive particle growth and aggregation through steric hindrance, thus ensuring the formation of well-dispersed microspheres. Furthermore, under alkaline and aerobic conditions, dopamine undergoes oxidative self-polymerization, forming a polydopamine functional shell on the surface of the calcium carbonate microspheres, further achieving sustained-release and controlled-release capabilities.

[0018] Optionally, in step S2, polydopamine-calcium carbonate microspheres are added to a cinnamaldehyde / rosemary extract ethanol solution, stirred in the dark for 12-24 hours, centrifuged at 10000 rpm for 5 minutes, the precipitate is collected, washed twice with ethanol, and freeze-dried to obtain composite microspheres.

[0019] In this invention, the encapsulation of cinnamaldehyde and rosemary extract is carried out under light-protected conditions to prevent degradation of the cinnamaldehyde and rosemary extract components.

[0020] Optionally, in step S2, the composite microspheres are further modified by adding the composite microspheres to deionized water, stirring magnetically for 5 minutes, adding a 0.5% phytic acid solution, stirring magnetically for 8-10 minutes, adjusting the pH to 5.5-6 with acetic acid solution, stirring continuously in the dark for 4-6 hours, centrifuging at 10,000 rpm for 10-15 minutes, collecting the precipitate, washing it with deionized water 3-5 times, and freeze-drying it to obtain phytic acid-composite microspheres.

[0021] This invention uses phytic acid to further modify the composite microspheres, forming a stable and dense phytic acid molecular layer on the surface of the polydopamine layer. The six phosphate groups in the phytic acid molecule exhibit negative charge in water, which can enhance the interaction with the MgO / SiO2 composite porous material and further improve the overall stability of the material. In addition, the introduction of phytic acid improves the overall material's chelating ability for metal ions in water, further inhibiting the oxidation reaction catalyzed by metal ions, thereby reducing the generation of certain oxidative odors.

[0022] Optionally, the cinnamaldehyde / rosemary extract ethanol solution is obtained by adding 2-3 parts by weight of cinnamaldehyde and 1.5-2 parts by weight of rosemary extract to 200 parts by volume of ethanol and stirring magnetically for 10-15 minutes.

[0023] Optionally, in step S3, the MgO / SiO2 composite porous material is added to deionized water, ultrasonically treated for 5 minutes, then composite microspheres are added, and the pH is adjusted to 5-6 with acetic acid solution. After stirring continuously for 8-12 hours, the mixture is vacuum filtered, washed 2-5 times with deionized water, and freeze-dried to obtain the antibacterial and deodorizing material.

[0024] The present invention also provides a long-lasting, controllable release antibacterial and deodorizing material for water treatment, comprising the following raw materials in parts by weight: 10-15 parts of MgO / SiO2 composite porous material and 3-8 parts of composite microspheres.

[0025] The above-described technical solution of the present invention has at least the following beneficial effects:

[0026] 1. This invention utilizes rice husks as a template to form a MgO / SiO2 composite porous material by calcining magnesium acetate and rice husks. Pretreatment preserves the rice husk framework and introduces MgO, endowing the material with a high specific surface area and positive charge, enhancing its adsorption capacity for anionic bacteria and pollutants, thereby improving its antibacterial effect.

[0027] 2. This invention utilizes polydopamine-calcium carbonate microspheres as a carrier to encapsulate cinnamaldehyde and rosemary extract, resulting in composite microspheres with long-lasting antibacterial and deodorizing functions. Cinnamaldehyde and rosemary extract eliminate odors at the source by inhibiting odor-causing microorganisms; in alkaline or neutral environments, cinnamaldehyde and rosemary extract components are slowly released; under acidic conditions, the calcium carbonate inside the polydopamine-calcium carbonate microspheres partially dissolves, accelerating the release of cinnamaldehyde and rosemary extract, enhancing the antibacterial effect, and achieving controllable long-lasting release.

[0028] 3. This invention uses MgO / SiO2 composite porous material to support composite microspheres. Utilizing its high specific surface area and porous structure, the adhesion of the microspheres is enhanced through physical adsorption. MgO provides long-lasting antibacterial and photocatalytic activity. Combined with the pH response control of the composite microspheres, the long-term release of antibacterial components is achieved, further improving the inhibition and removal of bacteria, mold, and odors in water. Attached Figure Description

[0029] Figure 1 Line graphs showing the long-lasting antibacterial rate of the antibacterial and deodorizing materials prepared in Example 1 and Comparative Examples 1-3 of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are some embodiments of the present invention, and all other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0031] Example 1

[0032] 70g of natural rice husks were placed in 800mL of 5% hydrochloric acid solution and vacuum-soaked at 10℃ for 24h. After filtration, the mixture was soaked in deionized water for 12h, filtered, and dried to obtain pretreated rice husk material. 40g of magnesium acetate was added to 700mL of ethanol-water solution (ethanol to water volume ratio of 1:1) and magnetically stirred for 5min to prepare magnesium acetate precursor solution. The pretreated rice husk material was immersed in the magnesium acetate precursor solution, allowed to stand for 72h, filtered, placed in a muffle furnace, calcined at 280℃ for 1.5h, heated to 420℃ and held for 2h, naturally cooled to room temperature, ground, and vacuum-dried at 60℃ for 6h to obtain MgO / SiO2 composite porous material.

[0033] Add 3g cinnamaldehyde and 1.5g rosemary extract to 200mL ethanol and stir magnetically for 15min to obtain a cinnamaldehyde / rosemary extract ethanol solution. Dissolve 4.6g gum arabic in 100mL deionized water and stir magnetically for 10min. Then add 1200mL deionized water, heat to 40℃, add 22g calcium chloride, and stir continuously for 15min. Add 20g sodium carbonate and maintain stirring at 40℃ for 5h. Centrifuge at 10000rpm for 15min, collect the precipitate, resuspend the precipitate in deionized water, sonicate for 30min, centrifuge again at 10000rpm for 15min, collect the precipitate, and add to 1.5L of ethanol. In 0.01 mol / L Tris-HCl buffer, after magnetic stirring for 10 min, 0.3 g of dopamine hydrochloride was slowly added. After stirring in the dark for 12 h, the mixture was centrifuged at 10000 rpm for 15 min, washed 5 times with deionized water, and freeze-dried to obtain polydopamine-calcium carbonate microspheres. These microspheres were then added to a cinnamaldehyde / rosemary extract ethanol solution, stirred in the dark for 24 h, centrifuged at 10000 rpm for 5 min, the precipitate was collected, washed twice with ethanol, and freeze-dried to obtain composite microspheres. These microspheres were then added to 100 mL of deionized water, magnetically stirred for 5 min, and then 100 mL of 0.5% phytic acid solution was added. The mixture was magnetically stirred for 10 min, the pH was adjusted to 5.5 with acetic acid solution, and the mixture was stirred continuously in the dark for 6 h. After centrifugation at 10000 rpm for 15 min, the precipitate was collected, washed 5 times with deionized water, and freeze-dried to obtain phytic acid-composite microspheres.

[0034] 12g of MgO / SiO2 composite porous material was added to 500mL of deionized water and sonicated for 5min. Then, 8g of phytic acid-composite microspheres were added, and the pH was adjusted to 5.5 with acetic acid solution. The mixture was stirred continuously for 12h, vacuum filtered, washed 5 times with deionized water, and freeze-dried to obtain the antibacterial and deodorizing material.

[0035] Example 2

[0036] 70g of natural rice husks were placed in 800mL of 5% hydrochloric acid solution and vacuum-soaked at 15℃ for 18h. After filtration, the mixture was soaked in deionized water for 10h, filtered, and dried to obtain pretreated rice husk material. 30g of magnesium acetate was added to 700mL of ethanol-water solution (ethanol to water volume ratio of 1:1) and magnetically stirred for 5min to prepare magnesium acetate precursor solution. The pretreated rice husk material was immersed in the magnesium acetate precursor solution, allowed to stand for 68h, filtered, placed in a muffle furnace, calcined at 250℃ for 1.5h, heated to 400℃ and held for 2h, naturally cooled to room temperature, ground, and vacuum-dried at 65℃ for 5h to obtain MgO / SiO2 composite porous material.

[0037] Add 2g of cinnamaldehyde and 1.5g of rosemary extract to 200mL of ethanol and stir magnetically for 10min to obtain a cinnamaldehyde / rosemary extract ethanol solution. Dissolve 4g of gum arabic in 100mL of deionized water and stir magnetically for 5min. Then add 1200mL of deionized water, heat to 40℃, add 20g of calcium chloride, and stir continuously for 10min. Then add 20g of sodium carbonate and maintain stirring at 40℃ for 3h. Centrifuge at 10000rpm for 10min, collect the precipitate, resuspend the precipitate in deionized water, sonicate for 20min, centrifuge again at 10000rpm for 10min, collect the precipitate, and add it to 1.5L of ethanol. In 0.01 mol / L Tris-HCl buffer, after magnetic stirring for 5 min, 0.2 g of dopamine hydrochloride was slowly added. After stirring in the dark for 10 h, the mixture was centrifuged at 10000 rpm for 10 min, washed twice with deionized water, and freeze-dried to obtain polydopamine-calcium carbonate microspheres. These microspheres were then added to a cinnamaldehyde / rosemary extract ethanol solution, stirred in the dark for 12 h, centrifuged at 10000 rpm for 5 min, and the precipitate was collected. The precipitate was washed twice with ethanol and freeze-dried to obtain composite microspheres. These microspheres were then added to 100 mL of deionized water, magnetically stirred for 5 min, and then 100 mL of 0.5% phytic acid solution was added. The mixture was magnetically stirred for 8 min, and the pH was adjusted to 5.5 with acetic acid solution. After stirring in the dark for 4 h, the mixture was centrifuged at 10000 rpm for 10 min, and the precipitate was collected. The precipitate was washed three times with deionized water and freeze-dried to obtain phytic acid-composite microspheres.

[0038] 10g of MgO / SiO2 composite porous material was added to 500mL of deionized water and sonicated for 5min. Then, 3g of phytic acid-composite microspheres were added, and the pH was adjusted to 6 with acetic acid solution. The mixture was stirred continuously for 8h, vacuum filtered, washed twice with deionized water, and freeze-dried to obtain the antibacterial and deodorizing material.

[0039] Example 3

[0040] 80g of natural rice husks were placed in 800mL of 5% hydrochloric acid solution and vacuum-soaked at 15℃ for 20h. After filtration, the rice husks were soaked in deionized water for 12h, filtered, and dried to obtain pretreated rice husk material. 35g of magnesium acetate was added to 700mL of ethanol-water solution (ethanol to water volume ratio of 1:1) and magnetically stirred for 5min to prepare magnesium acetate precursor solution. The pretreated rice husk material was immersed in the magnesium acetate precursor solution, allowed to stand for 70h, filtered, placed in a muffle furnace, calcined at 280℃ for 2h, heated to 430℃ and held for 2h, naturally cooled to room temperature, ground, and vacuum-dried at 70℃ for 6h to obtain MgO / SiO2 composite porous material.

[0041] Add 3g cinnamaldehyde and 2g rosemary extract to 200mL ethanol and stir magnetically for 12min to obtain a cinnamaldehyde / rosemary extract ethanol solution. Dissolve 5g gum arabic in 100mL deionized water and stir magnetically for 10min. Then add 1200mL deionized water, heat to 40℃, add 25g calcium chloride, and stir continuously for 12min. Then add 22g sodium carbonate and maintain stirring at 40℃ for 4h. Centrifuge at 10000rpm for 14min, collect the precipitate, resuspend the precipitate in deionized water, sonicate for 25min, centrifuge again at 10000rpm for 14min, collect the precipitate, and add to 1.5L of [unclear - possibly a container or container]. In 0.01 mol / L Tris-HCl buffer, after magnetic stirring for 8 min, 0.25 g of dopamine hydrochloride was slowly added. After stirring in the dark for 11 h, the mixture was centrifuged at 10,000 rpm for 14 min, washed 4 times with deionized water, and freeze-dried to obtain polydopamine-calcium carbonate microspheres. These microspheres were then added to cinnamaldehyde / rosemary extract ethanol solution, stirred in the dark for 18 h, centrifuged at 10,000 rpm for 5 min, the precipitate was collected, washed twice with ethanol, and freeze-dried to obtain composite microspheres. These microspheres were then added to 100 mL of deionized water, magnetically stirred for 5 min, and then 100 mL of 0.5% phytic acid solution was added. The mixture was magnetically stirred for 9 min, the pH was adjusted to 5.7 with acetic acid solution, and the mixture was stirred continuously in the dark for 5 h. After centrifugation at 10,000 rpm for 12 min, the precipitate was collected, washed 4 times with deionized water, and freeze-dried to obtain phytic acid-composite microspheres.

[0042] 12g of MgO / SiO2 composite porous material was added to 500mL of deionized water and sonicated for 5min. Then, 6g of phytic acid-composite microspheres were added, and the pH was adjusted to 5.6 with acetic acid solution. The mixture was stirred continuously for 9h, vacuum filtered, washed 4 times with deionized water, and freeze-dried to obtain the antibacterial and deodorizing material.

[0043] Example 4

[0044] 72g of natural rice husks were placed in 800mL of 5% hydrochloric acid solution and vacuum-soaked at 13℃ for 22h. After filtration, the mixture was soaked in deionized water for 11h, filtered, and dried to obtain pretreated rice husk material. 33g of magnesium acetate was added to 700mL of ethanol-water solution (ethanol to water volume ratio of 1:1) and magnetically stirred for 5min to prepare magnesium acetate precursor solution. The pretreated rice husk material was immersed in the magnesium acetate precursor solution, allowed to stand for 69h, filtered, placed in a muffle furnace, calcined at 260℃ for 1.8h, heated to 410℃ and held for 2h, naturally cooled to room temperature, ground, and vacuum-dried at 65℃ for 5.5h to obtain MgO / SiO2 composite porous material.

[0045] Add 2.5g cinnamaldehyde and 1.8g rosemary extract to 200mL ethanol and stir magnetically for 12min to obtain a cinnamaldehyde / rosemary extract ethanol solution. Dissolve 4g gum arabic in 100mL deionized water and stir magnetically for 6min. Then add 1200mL deionized water, heat to 40℃, add 21g calcium chloride, and stir continuously for 13min. Then add 21g sodium carbonate and maintain stirring at 40℃ for 3.5h. Centrifuge at 10000rpm for 12min, collect the precipitate, resuspend the precipitate in deionized water, sonicate for 25min, centrifuge again at 10000rpm for 12min, collect the precipitate, and add to 1.5L of ethanol solution. In 0.01 mol / L Tris-HCl buffer, after magnetic stirring for 8 min, 0.26 g of dopamine hydrochloride was slowly added. After stirring in the dark for 11 h, the mixture was centrifuged at 10,000 rpm for 12 min, washed three times with deionized water, and freeze-dried to obtain polydopamine-calcium carbonate microspheres. These microspheres were then added to a cinnamaldehyde / rosemary extract ethanol solution, stirred in the dark for 20 h, centrifuged at 10,000 rpm for 5 min, and the precipitate was collected. The precipitate was washed twice with ethanol and freeze-dried to obtain composite microspheres. These microspheres were then added to 100 mL of deionized water, stirred magnetically for 5 min, and then 100 mL of 0.5% phytic acid solution was added. The mixture was magnetically stirred for 9 min, and the pH was adjusted to 5.8 with acetic acid solution. After stirring continuously in the dark for 4.5 h, the mixture was centrifuged at 10,000 rpm for 12 min, and the precipitate was collected. The precipitate was washed four times with deionized water and freeze-dried to obtain phytic acid-composite microspheres.

[0046] 12g of MgO / SiO2 composite porous material was added to 500mL of deionized water and sonicated for 5min. Then, 4g of phytic acid-composite microspheres were added, and the pH was adjusted to 5 with acetic acid solution. The mixture was stirred continuously for 10h, vacuum filtered, washed three times with deionized water, and freeze-dried to obtain the antibacterial and deodorizing material.

[0047] Example 5

[0048] 76g of natural rice husks were placed in 800mL of 5% hydrochloric acid solution and vacuum-soaked at 12℃ for 21h. After filtration, the mixture was soaked in deionized water for 11h, filtered, and dried to obtain pretreated rice husk material. 35g of magnesium acetate was added to 700mL of ethanol-water solution (ethanol to water volume ratio of 1:1) and magnetically stirred for 5min to prepare magnesium acetate precursor solution. The pretreated rice husk material was immersed in the magnesium acetate precursor solution, allowed to stand for 70h, filtered, placed in a muffle furnace, calcined at 270℃ for 1.6h, heated to 420℃ and held for 2h, naturally cooled to room temperature, ground, and vacuum-dried at 70℃ for 5.5h to obtain MgO / SiO2 composite porous material.

[0049] Add 2g of cinnamaldehyde and 2g of rosemary extract to 200mL of ethanol and stir magnetically for 10min to obtain a cinnamaldehyde / rosemary extract ethanol solution. Dissolve 5g of gum arabic in 100mL of deionized water and stir magnetically for 5min. Then add 1200mL of deionized water, heat to 40℃, add 25g of calcium chloride, and stir continuously for 15min. Then add 20g of sodium carbonate and maintain stirring at 40℃ for 3h. Centrifuge at 10000rpm for 15min, collect the precipitate, resuspend the precipitate in deionized water, sonicate for 20min, centrifuge again at 10000rpm for 15min, collect the precipitate, and add it to 1.5L of ethanol solution. In 0.01 mol / L Tris-HCl buffer, after magnetic stirring for 5 min, 0.3 g of dopamine hydrochloride was slowly added. After stirring in the dark for 10 h, the mixture was centrifuged at 10000 rpm for 10 min, washed twice with deionized water, and freeze-dried to obtain polydopamine-calcium carbonate microspheres. These microspheres were then added to a cinnamaldehyde / rosemary extract ethanol solution, stirred in the dark for 16 h, centrifuged at 10000 rpm for 5 min, and the precipitate was collected. The precipitate was washed twice with ethanol and freeze-dried to obtain composite microspheres. These microspheres were then added to 100 mL of deionized water, magnetically stirred for 5 min, and then 100 mL of 0.5% phytic acid solution was added. The mixture was magnetically stirred for 10 min, the pH was adjusted to 6 with acetic acid solution, and the mixture was stirred continuously in the dark for 6 h. The precipitate was collected, washed three times with deionized water, and freeze-dried to obtain phytic acid-composite microspheres.

[0050] 15g of MgO / SiO2 composite porous material was added to 500mL of deionized water and sonicated for 5min. Then, 6g of phytic acid-composite microspheres were added, and the pH was adjusted to 6 with acetic acid solution. The mixture was stirred continuously for 8h, vacuum filtered, washed 5 times with deionized water, and freeze-dried to obtain the antibacterial and deodorizing material.

[0051] Example 6

[0052] 70g of natural rice husks were placed in 800mL of 5% hydrochloric acid solution and vacuum-soaked at 10℃ for 24h. After filtration, the mixture was soaked in deionized water for 12h, filtered, and dried to obtain pretreated rice husk material. 40g of magnesium acetate was added to 700mL of ethanol-water solution (ethanol to water volume ratio of 1:1) and magnetically stirred for 5min to prepare magnesium acetate precursor solution. The pretreated rice husk material was immersed in the magnesium acetate precursor solution, allowed to stand for 72h, filtered, placed in a muffle furnace, calcined at 280℃ for 1.5h, heated to 420℃ and held for 2h, naturally cooled to room temperature, ground, and vacuum-dried at 60℃ for 6h to obtain MgO / SiO2 composite porous material.

[0053] Add 3g cinnamaldehyde and 1.5g rosemary extract to 200mL ethanol and stir magnetically for 15min to obtain a cinnamaldehyde / rosemary extract ethanol solution. Dissolve 4.6g gum arabic in 100mL deionized water and stir magnetically for 10min. Then add 1200mL deionized water, heat to 40℃, add 22g calcium chloride, and stir continuously for 15min. Add 20g sodium carbonate and maintain stirring at 40℃ for 5h. Centrifuge at 10000rpm for 15min, collect the precipitate, resuspend the precipitate in deionized water, sonicate for 30min, centrifuge again at 10000rpm for 15min, collect the precipitate, and add to 1.5L of ethanol. In 0.01 mol / L Tris-HCl buffer, after magnetic stirring for 10 min, 0.3 g of dopamine hydrochloride was slowly added. After stirring in the dark for 12 h, the mixture was centrifuged at 10,000 rpm for 15 min, washed 5 times with deionized water, and freeze-dried to obtain polydopamine-calcium carbonate microspheres. These microspheres were then added to a cinnamaldehyde / rosemary extract ethanol solution, stirred in the dark for 24 h, centrifuged at 10,000 rpm for 5 min, the precipitate was collected, washed twice with ethanol, and freeze-dried to obtain composite microspheres.

[0054] 12g of MgO / SiO2 composite porous material was added to 500mL of deionized water and sonicated for 5min. Then, 8g of composite microspheres were added and the pH was adjusted to 5.5 with acetic acid solution. The mixture was stirred continuously for 12h, vacuum filtered, washed 5 times with deionized water, and freeze-dried to obtain the antibacterial and deodorizing material.

[0055] The present invention also includes comparative examples and related experiments.

[0056] Comparative Example 1

[0057] Compared with Example 1, the only difference is that SiO2 porous material is used instead of MgO / SiO2 composite porous material. The other preparation methods and components are completely the same, and the antibacterial and deodorizing material is finally obtained.

[0058] Comparative Example 2

[0059] Compared with Example 1, the only difference is that calcium carbonate microspheres are used instead of polydopamine-calcium carbonate microspheres. The other preparation methods and components are completely the same, and the antibacterial and deodorizing material is finally obtained.

[0060] Comparative Example 3

[0061] Compared with Example 1, the only difference is that the prepared MgO / SiO2 composite porous material is directly used as the antibacterial and deodorizing material.

[0062] Performance testing

[0063] I. Antibacterial Performance Test

[0064] This experiment tested the antibacterial and deodorizing properties of the antibacterial materials prepared in Examples 1-6 and Comparative Examples 1-3. 200 mL of circulating cooling water sample and 1 mL of bacterial suspension (Staphylococcus aureus and Escherichia coli, concentration approximately 1×10⁻⁶) were taken. 6 The samples were mixed with CFU / mL, and then 20 mg of the antibacterial and deodorizing materials prepared in Examples 1-6 and Comparative Examples 1-3 were added respectively. Blank samples without antibacterial and deodorizing materials were also prepared. After shaking and incubating at 37°C for 24 h, the number of colonies in the samples was counted according to GB / T5750.12-2023 Standard Test Methods for Drinking Water Part 12: Microbiological Indicators. The antibacterial rate was calculated according to the following formula to evaluate the antibacterial effect of different antibacterial and deodorizing materials.

[0065]

[0066] In the formula, A0 represents the number of colonies in the blank sample. The number of colonies in the test sample is shown in Table 1; the specific antibacterial performance test results are shown in Table 1.

[0067] Table 1: Results of Antibacterial Performance Test

[0068]

[0069] As shown in Table 1, Examples 1-5 all exhibited extremely strong and broad-spectrum antibacterial properties (>99.4%). Example 6, which did not use phytic acid to modify the composite microspheres, showed a slight decrease in antibacterial rate, demonstrating that phytic acid can enhance performance by strengthening cross-linking, stabilizing the structure, and synergistically combating bacteria, but it was still significantly better than Comparative Examples 1-3. Compared to Example 1, the absence of MgO in Comparative Example 1 significantly reduced the antibacterial performance, proving that MgO also possesses a certain antibacterial ability and is an indispensable part of the system. The absence of polydopamine in Comparative Example 2 also significantly reduced the antibacterial rate. Comparative Example 3, which directly used the prepared MgO / SiO2 composite porous material as an antibacterial and deodorizing material, showed the weakest antibacterial properties, indicating that while the simple MgO / SiO2 composite porous material has some effect, it is far inferior to the antibacterial and deodorizing material loaded with composite microspheres containing cinnamaldehyde and rosemary extract.

[0070] II. Deodorization Performance Test

[0071] First, prepare water samples with characteristic odors: (1) Musty water sample: prepare a musty sample solution with a concentration of 100 ng / L using geosmin and 2-MIB respectively; (2) Rotten water sample: prepare a rotten sample solution with a concentration of 0.5 mg / L using sodium sulfide and ammonium chloride respectively.

[0072] Then, 150 mL of odorous water sample was placed in each reaction bottle, and 0.15 g of the antibacterial and deodorizing materials prepared in Examples 1-6 and Comparative Examples 1-3 were added respectively. At the same time, blank samples without antibacterial and deodorizing materials were set up. The bottle mouths were sealed, and the mixture was shaken at 25℃ (150 rpm) for 24 h. After that, samples were taken, and the contents of geosmin and 2-MIB were detected according to the "HJ / 810-2016 Headspace / Gas Chromatography-Mass Spectrometry Method", the contents of sulfides were detected according to the "HJ / 1226-2021 Methylene Blue Spectrophotometry Method", and the contents of ammonia nitrogen were detected according to the "HJ / 535-2009 Nessler's Reagent Spectrophotometry Method". The removal rates of geosmin, 2-MIB, sulfides and ammonia nitrogen were calculated according to the following formula.

[0073]

[0074] In the formula, C0 is the initial concentration of the blank sample. The concentration of the test sample solution after 24 hours is shown in Table 2; the specific deodorization performance test results are shown in Table 2.

[0075] Table 2: Deodorization Performance Test Results

[0076]

[0077] As shown in Table 2, Example 1 exhibits extremely high removal rates for all four representative odor-causing substances, demonstrating highly efficient deodorization capabilities. Example 6 shows slightly weaker overall deodorization performance compared to Examples 1-5, but it is still superior to Comparative Examples 1-3. Compared to Example 1, the absence of MgO in Comparative Example 1 significantly reduces the overall deodorization effect, demonstrating the important role of MgO in enhancing overall deodorization efficiency. The absence of polydopamine in Comparative Example 2 also leads to a decrease in all removal rates. Comparative Example 3, which directly uses the prepared MgO / SiO2 composite porous material as an antibacterial and deodorizing material, shows the worst removal effect for ammonia nitrogen.

[0078] III. Long-term effectiveness evaluation

[0079] To evaluate the long-lasting effect of the antibacterial and deodorizing materials prepared in this invention, the antibacterial and deodorizing materials prepared in Example 1 and Comparative Examples 1-3 were subjected to a mixture of circulating cooling water sample and 1 mL of Escherichia coli suspension (concentration approximately 1 × 10⁻⁶). 6 The samples were cultured in a mixed suspension containing CFU / mL, and samples were taken on days 1, 10, 20, and 30 of culture. The number of colonies in the samples was counted according to GB / T5750.12-2023 Standard Examination Methods for Drinking Water – Part 12: Microbiological Indicators, and the inhibition rate was calculated to evaluate the long-lasting antibacterial performance and further reflect the long-lasting effect of the antibacterial and deodorizing material prepared by this invention. The final results are shown in [Figure number missing]. Figure 1 .

[0080] from Figure 1 As can be clearly seen, the antibacterial rate of Example 1 remained above 95% throughout the 30-day test period, demonstrating extremely excellent long-lasting antibacterial performance. In contrast, the absence of the polydopamine component in Comparative Example 2 resulted in the most significant decrease in the antibacterial rate over time, while Comparative Examples 1 and 3 also showed a significant decrease in their antibacterial rates.

[0081] In summary, the antibacterial and deodorizing material prepared by this invention has excellent antibacterial and deodorizing capabilities, and can achieve controlled release during water treatment, thus exerting a long-lasting effect.

[0082] The above are preferred embodiments of the present invention. Those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a long-acting controllable release antibacterial deodorant material for water treatment, characterized by, Includes the following steps: S1. The pretreated rice husk material is immersed in a magnesium acetate precursor solution, allowed to stand, filtered, calcined, cooled, ground, and dried to obtain MgO / SiO2 composite porous material. S2. Add polydopamine-calcium carbonate microspheres to cinnamaldehyde / rosemary extract ethanol solution, stir in the dark for 12-24 hours, centrifuge at 10000 rpm for 5 minutes, collect the precipitate, wash twice with ethanol, freeze dry to obtain composite microspheres. S3. Add the MgO / SiO2 composite porous material to deionized water, sonicate, add composite microspheres, adjust the pH to acidic, stir continuously, vacuum filter, wash, and freeze dry to obtain the antibacterial and deodorizing material. The polydopamine-calcium carbonate microspheres were prepared by dissolving 4-5 parts by weight of gum arabic in 100 parts by volume of deionized water, stirring magnetically for 5-10 minutes, then adding 1200 parts by volume of deionized water, heating to 40°C, adding 20-25 parts by weight of calcium chloride, stirring continuously for 10-15 minutes, then adding 20-22 parts by weight of sodium carbonate, and maintaining stirring at 40°C for 3-5 hours. The mixture was then centrifuged at 10000 rpm for 10-15 minutes, the precipitate was collected, and the precipitate was rehydrated with deionized water. Suspend the precipitate, sonicate for 20-30 min, then centrifuge at 10000 rpm for 10-15 min, collect the precipitate, add it to 1500 volumes of 0.01 mol / L Tris-HCl buffer, stir magnetically for 5-10 min, add 0.2-0.3 parts by weight of dopamine hydrochloride, stir in the dark for 10-12 h, centrifuge at 10000 rpm for 10-15 min, wash 2-5 times with deionized water, and freeze dry to obtain the final product.

2. The method for preparing a long-lasting, controllable-release antibacterial and deodorizing material for water treatment according to claim 1, characterized in that, The pretreated rice husk material is obtained by placing 70-80 parts by weight of rice husk into 800 parts by volume of a 5% hydrochloric acid solution, vacuum soaking at 10-15°C for 18-24 hours, filtering, soaking in deionized water for 10-12 hours, filtering and drying.

3. The method for preparing a long-lasting, controllable-release antibacterial and deodorizing material for water treatment according to claim 1, characterized in that, The magnesium acetate precursor solution is obtained by adding 30-40 parts by mass of magnesium acetate to 700 parts by volume of an aqueous ethanol solution and stirring magnetically for 5 minutes; the volume ratio of ethanol to water in the aqueous ethanol solution is 1:

1.

4. The method for preparing a long-lasting, controllable-release antibacterial and deodorizing material for water treatment according to claim 1, characterized in that, In step S1, the pretreated rice husk material is immersed in a magnesium acetate precursor solution, left to stand for 68-72 hours, filtered, placed in a muffle furnace, calcined at 250-280°C for 1.5-2 hours, then heated to 400-430°C and held for 2 hours, naturally cooled to room temperature, ground, and vacuum dried at 60-70°C for 5-6 hours to obtain the MgO / SiO2 composite porous material.

5. The method for preparing a long-lasting, controllable-release antibacterial and deodorizing material for water treatment according to claim 1, characterized in that, In step S2, the composite microspheres were further modified by adding them to deionized water and stirring magnetically for 5 minutes. Then, a 0.5% phytic acid solution was added and stirred magnetically for 8-10 minutes. The pH was adjusted to 5.5-6 using acetic acid solution and stirred continuously in the dark for 4-6 hours. The mixture was then centrifuged at 10,000 rpm for 10-15 minutes, the precipitate was collected, washed 3-5 times with deionized water, and freeze-dried to obtain phytic acid-composite microspheres.

6. The method for preparing a long-lasting, controllable-release antibacterial and deodorizing material for water treatment according to claim 1, characterized in that, The cinnamaldehyde / rosemary extract ethanol solution is obtained by adding 2-3 parts by weight of cinnamaldehyde and 1.5-2 parts by weight of rosemary extract to 200 parts by volume of ethanol and stirring magnetically for 10-15 minutes.

7. The method for preparing a long-lasting, controllable-release antibacterial and deodorizing material for water treatment according to claim 1, characterized in that, In step S3, the MgO / SiO2 composite porous material is added to deionized water, ultrasonically treated for 5 minutes, then composite microspheres are added, and the pH is adjusted to 5-6 with acetic acid solution. After stirring continuously for 8-12 hours, the mixture is vacuum filtered, washed 2-5 times with deionized water, and freeze-dried to obtain the antibacterial and deodorizing material.

8. A long-lasting, controllable-release antibacterial and deodorizing material for water treatment, characterized in that, The material is prepared using the method described in any one of claims 1 to 7, comprising the following raw materials in parts by weight: 10 to 15 parts of MgO / SiO2 composite porous material and 3 to 8 parts of composite microspheres.

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