Air sterilizing adsorbing material and preparation method thereof

Abstract

The application discloses an air sterilization and adsorption material and a preparation method thereof, and comprises the following steps: S1, preparation of composite diatomite; S2, preparation of mercapto-modified composite diatomite; S3, preparation of functionalized composite diatomite; S4, the functionalized diatomite is added into an ascorbic acid solution, ultrasonic dispersion is carried out, a mixed solution of copper nitrate and silver nitrate is added dropwise under vigorous stirring, after the dropwise addition is completed, constant-temperature reaction is carried out under a nitrogen atmosphere, and after the reaction is completed, the air sterilization and adsorption material is obtained. The air sterilization and adsorption material prepared by the method combines physical adsorption, electrostatic adsorption, chemical anchoring, contact sterilization and ion sterilization and other action mechanisms, realizes efficient and synergistic removal of particulate pollutants (such as PM2.5) and microorganisms in air, solves the technical problems that traditional adsorption materials are single in function and sterilization materials are easy to fail, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of air purification materials technology, specifically relating to an air sterilization and adsorption material and its preparation method. Background Technology

[0002] With the acceleration of industrialization and people's increasing demands for a healthy living environment, air pollution, especially particulate matter (such as PM2.5), volatile organic compounds (VOCs), and microbial pollution such as bacteria and viruses in indoor air, has become a major threat to human health. To address this issue, the development of highly efficient air purification materials and technologies has received widespread attention. Among these, air-sterilizing adsorption materials are a key type of functional material. They aim to capture and remove air pollutants through physical adsorption, chemical adsorption, or catalytic degradation, while simultaneously using loaded antibacterial substances or their own inherent antibacterial activity to kill attached microorganisms, thereby achieving the dual purpose of purifying the air and inhibiting the spread of pathogens. Currently, common materials of this type on the market mainly include activated carbon or molecular sieves loaded with metal ions (such as silver, copper, and zinc), and porous carriers with surfaces modified with antibacterial agents (such as quaternary ammonium salts).

[0003] However, existing air purification adsorption materials still have many shortcomings, limiting their purification efficiency and service life. First, many materials have limited functionality; some have excellent adsorption performance but insufficient bactericidal ability, while others have strong bactericidal activity but limited pollutant capture capacity, making it difficult to achieve efficient synergistic purification. Second, the bactericidal active components (such as metal nanoparticles) and the carrier are usually simply physically loaded with weak binding forces, making them prone to detachment and loss during long-term use. This not only leads to rapid degradation of bactericidal performance but also risks secondary pollution from the detached nanoparticles. Furthermore, some active components (especially non-precious metals such as copper) are chemically reactive and easily oxidized and deactivated in the usage environment, resulting in poor long-term stability of the material. Therefore, how to achieve a firm anchorage and long-term stability of the bactericidal active components on the carrier through reasonable structural design and material composites, while ensuring high adsorption capacity, is a key technical challenge that urgently needs to be solved in the field of air purification materials. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an air sterilization adsorption material and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing an air sterilization adsorbent material includes the following steps:

[0007] S1. Add alkali lignin to concentrated sulfuric acid and stir at a constant temperature to obtain sulfonated lignin; add chitosan to dilute acetic acid solution, stir to dissolve, then add sulfonated lignin, stir evenly, then add aminated diatomaceous earth and glutaraldehyde, and heat to react. After the reaction is completed, filter, wash, dry and carbonize to obtain composite diatomaceous earth.

[0008] S2. Add the composite diatomaceous earth from step S1 to an ethanol aqueous solution, then add γ-mercaptopropyltrimethoxysilane, and carry out a constant temperature reaction under a nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain mercapto-modified composite diatomaceous earth.

[0009] S3. Add the thiolized composite diatomaceous earth from step S2 to the mixed solvent, then add 2,3-epoxypropyltrimethylammonium chloride and triethylamine, and carry out a constant temperature reaction under a nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain functionalized composite diatomaceous earth.

[0010] S4. Add the functionalized diatomaceous earth from step S3 to the ascorbic acid solution, disperse it by ultrasonication, and add a mixed solution of copper nitrate and silver nitrate dropwise under vigorous stirring. After the addition is complete, carry out a constant temperature reaction under a nitrogen atmosphere. After the reaction is complete, filter, wash and dry to obtain the air sterilization adsorbent material.

[0011] Preferably, the preparation method of the aminated diatomaceous earth in step S1 is as follows: Diatomaceous earth is added to hydrochloric acid solution for impregnation treatment. After the treatment is completed, it is filtered, washed, dried and calcined. Then, the solid product is added to an ethanol aqueous solution, followed by the addition of γ-aminopropyltriethoxysilane for stirring reaction. After the reaction is completed, it is filtered, washed and dried to obtain the product.

[0012] Preferably, the concentration of the hydrochloric acid is 4-6 mol / L, the impregnation treatment temperature is 80-90℃ and the time is 1-2 h, the calcination temperature is 500-550℃ and the time is 2-3 h; the mass ratio of the solid product to γ-aminopropyltriethoxysilane is 100:8-12, and the stirring reaction temperature is 50-60℃ and the time is 2-3 h.

[0013] In this invention, acid leaching activation removes impurities that clog the natural pores of diatomaceous earth, clearing the pores and generating more silanol groups on the surface, which serve as active sites for subsequent chemical reactions. Subsequently, it reacts with γ-aminopropyltriethoxysilane to graft amino functional groups onto the surface of the diatomaceous earth framework, enabling the inorganic diatomaceous earth to be tightly bonded to subsequent organic polymers (lignin, chitosan) through chemical bonds.

[0014] Preferably, in step S1, the mass ratio of alkali lignin to concentrated sulfuric acid is 50-60:200-300, and the constant temperature stirring is 55-65℃ for 2-3 hours.

[0015] Preferably, in step S1, the mass ratio of chitosan, dilute acetic acid solution, sulfonated lignin, pretreated diatomaceous earth, and glutaraldehyde is 20-30:1000-1500:20-30:90-100:40-50, the heating reaction temperature is 70-80℃, the time is 4-5h, and the carbonization process is as follows: heating to 300-350℃ at a rate of 2-3℃ / min, holding for 2-3h, and then heating to 600-650℃ at a rate of 4-5℃ / min, holding for 1-2h.

[0016] In this invention, alkali lignin is rich in benzene ring structures. Sulfonation of lignin introduces sulfonic acid groups, which increase its dispersibility in aqueous systems. Chitosan is rich in nitrogen, and carbonization enables in-situ nitrogen doping of carbon materials. The carbon network formed after carbonization greatly improves the specific surface area and adsorption capacity of the material. The components are firmly bonded together by chemical bonding to form a stable three-dimensional network structure, ensuring that it does not collapse during the carbonization process and guaranteeing the porous structure of the material.

[0017] Preferably, in step S2, the mass ratio of the composite diatomaceous earth to γ-mercaptopropyltrimethoxysilane is 100:8-11, and the isothermal reaction is carried out at a temperature of 70-75°C for 4-6 hours.

[0018] In this invention, by reacting composite diatomaceous earth with γ-mercaptopropyltrimethoxysilane, thiol groups are introduced onto the diatomaceous earth. On the one hand, these thiol groups can serve as reaction sites for subsequent reactions with 2,3-epoxypropyltrimethylammonium chloride. On the other hand, thiol groups are typical soft nucleophilic groups with extremely strong affinity and coordination ability for silver and copper metal ions. They can firmly anchor the subsequently loaded silver and copper nanoparticles to the material surface through strong chemical bonds, preventing the problem of subsequent detachment.

[0019] Preferably, in step S3, the mass ratio of the thiolized composite diatomaceous earth, 2,3-epoxypropyltrimethylammonium chloride, and triethylamine is 100:3.1-4.3:0.5-1, and the isothermal reaction is carried out at a temperature of 45-55°C for 3-5 hours.

[0020] In this invention, by reacting mercapto-modified composite diatomaceous earth with 2,3-epoxypropyltrimethylammonium chloride, the 2,3-epoxypropyltrimethylammonium chloride has a positively charged hydrophilic head (quaternary ammonium group), which can actively attract and capture bacteria, viruses and some dust particles that are usually negatively charged in the air, thereby improving the adsorption performance of the material.

[0021] Preferably, the mass concentration of the ascorbic acid solution in step S4 is 5-8 g / L, the concentration of copper nitrate in the mixed solution is 5-8 g / L, and the concentration of silver nitrate is 10-15 g / L.

[0022] Preferably, in step S4, the mass-to-volume ratio of the functionalized diatomaceous earth, ascorbic acid solution, and mixed solution is 100g:900-1100mL:200-300mL, and the isothermal reaction is carried out at a temperature of 55-65℃ for 4-5 hours.

[0023] In this invention, ascorbic acid is used as a reducing agent to reduce silver and copper ions in situ into nano-metal particles, which are then firmly loaded onto functionalized diatomaceous earth. Silver has a broad-spectrum and highly efficient bactericidal ability, while copper not only has its own bactericidal ability but also forms a synergistic effect with silver and can effectively kill bacteria that are resistant to silver, thus achieving a balance of high efficiency, broad spectrum, and low cost.

[0024] This invention also protects an air sterilization adsorbent material prepared by the method described above.

[0025] The present invention also protects the application of an air sterilization adsorption material as described above in a high-oxygen membrane.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The air sterilization adsorbent material provided by the present invention uses acid-activated and surface-functionalized diatomaceous earth as a rigid framework, then chemically bonds it with chitosan and carbonizes it at high temperature. On this basis, through surface chemical modification, thiol functional groups as metal anchoring points and quaternary ammonium salts that give the material positive charge adsorption capacity are introduced in sequence, and finally silver-copper bimetallic nanoparticles are loaded in situ. The air sterilization adsorbent material prepared by this method combines multiple mechanisms of action such as physical adsorption, electrostatic adsorption, chemical anchoring, contact sterilization and ion sterilization, and achieves efficient synergistic removal of particulate pollutants (such as PM2.5) and microorganisms in the air. It solves the technical problems of single function of traditional adsorbent materials and easy failure of sterilization materials, and has broad application prospects.

[0028] (2) The air sterilization adsorption material provided by the present invention uses diatomaceous earth as raw material. It is first activated by acid leaching, then amino groups are introduced, and then alkali lignin and chitosan are introduced on the diatomaceous earth by chemical bonding. Then it is carbonized to obtain a porous structure with strong adsorption capacity. This method of preparing composite carrier by first chemical bonding and then in-situ carbonization forms a stable and uniform organic-inorganic hybrid structure before carbonization, which effectively avoids the common problems of organic phase agglomeration and macroscopic phase separation in physical coating method. This allows the decomposition, gasification and atomic recombination of organic components to be carried out under spatially bound and highly controllable conditions during subsequent high-temperature carbonization, thereby generating an ultrathin and orderly carbon layer uniformly coated on the pore wall of diatomaceous earth, rather than the thick carbon block that blocks the pores in physical coating method. Finally, a composite diatomaceous earth with a larger specific surface area and a more stable structure is obtained.

[0029] (3) The air sterilization adsorption material provided by the present invention introduces thiol groups and 2,3-epoxypropyltrimethylammonium chloride sequentially onto composite diatomaceous earth. On the one hand, some of the thiol groups react with 2,3-epoxypropyltrimethylammonium chloride, and 2,3-epoxypropyltrimethylammonium chloride with positive charge adsorption function is introduced into diatomaceous earth in a chemical bond manner, thereby improving the material's ability to actively attract and capture bacteria, viruses and some dust particles that are usually negatively charged in the air. On the other hand, the remaining unreacted thiol groups can react with Ag introduced in subsequent steps. + Cu 2+ The silver-copper nanoparticles are firmly anchored to the carrier surface by forming extremely strong coordination bonds (MS bonds) with soft metal ions, effectively preventing the migration and loss of active components during use, and significantly enhancing the stability and service life of the air sterilization adsorption material. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0032] The particle size of the diatomaceous earth is 20-50 μm.

[0033] Example 1

[0034] A method for preparing an air sterilization adsorbent material includes the following steps:

[0035] S1. 150g of diatomaceous earth was added to 1L of 5mol / L hydrochloric acid solution and impregnated at 85℃ for 1.5h. After treatment, the mixture was filtered, washed, and dried, and then calcined at 530℃ for 2.5h to obtain a solid product. Subsequently, 100g of the solid product was added to 1L of ethanol-water solution (ethanol to water volume ratio of 9:1), followed by the addition of 10g of γ-aminopropyltriethoxysilane. The mixture was stirred and reacted at 55℃ for 2.5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain aminated diatomaceous earth.

[0036] S2. Add 55g of alkali lignin to 250mL of 98% concentrated sulfuric acid and stir at 60℃ for 2.5h. Then slowly add 2kg of an ice-water mixture (ice to water mass ratio of 1:1), filter, add sodium chloride to the filtrate and stir vigorously until no more precipitate forms. Then centrifuge, wash and dry the solid product to obtain sulfonated lignin. Add 25g of chitosan to 1300g of 2% dilute acetic acid solution and stir. After dissolving, add 25g of sulfonated lignin, stir evenly, then add 95g of aminated diatomaceous earth and 45g of glutaraldehyde from step S1, adjust the pH to 4, and react at 75℃ for 4.5h. After the reaction is complete, filter, wash, dry, and carbonize. The carbonization process is as follows: under a nitrogen atmosphere, heat to 330℃ at a rate of 2.5℃ / min, hold for 2.5h, then heat to 630℃ at a rate of 4.5℃ / min, and hold for 1.5h to obtain composite diatomaceous earth.

[0037] S3. Add 100g of composite diatomaceous earth from step S2 to 1L of ethanol aqueous solution (ethanol to water volume ratio of 9:1), then add 10g of γ-mercaptopropyltrimethoxysilane, and react at a constant temperature of 72℃ for 5h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain mercapto-modified composite diatomaceous earth.

[0038] S4. Add 100g of thiolized composite diatomaceous earth from step S3 to 1L of mixed solvent (ethanol and DMF in a volume ratio of 8:2), then add 3.8g of 2,3-epoxypropyltrimethylammonium chloride and 0.8g of triethylamine. React at a constant temperature of 50℃ for 4h under a nitrogen atmosphere. After the reaction is complete, filter, wash and dry to obtain functionalized composite diatomaceous earth.

[0039] S5. Add 100g of functionalized diatomaceous earth from step S4 to 1000mL of ascorbic acid solution with a concentration of 7g / L, and sonicate for 20min. Under vigorous stirring (stirring speed of 700r / min), add 250mL of a mixed solution of copper nitrate and silver nitrate (concentration of copper nitrate is 7g / L, concentration of silver nitrate is 13g / L) dropwise over a time of 45min. After the addition is complete, react at a constant temperature of 60℃ for 4.5h under a nitrogen atmosphere. After the reaction is complete, filter, wash, and dry to obtain the air sterilization adsorbent material.

[0040] Example 2

[0041] A method for preparing an air sterilization adsorbent material includes the following steps:

[0042] S1. Add 150g of diatomaceous earth to 1L of 4mol / L hydrochloric acid solution and impregnate at 80℃ for 2h. After treatment, filter, wash, and dry, and calcine at 500℃ for 3h to obtain a solid product. Then add 100g of the solid product to 1L of ethanol aqueous solution (ethanol to water volume ratio of 9:1), followed by 8g of γ-aminopropyltriethoxysilane. Stir and react at 50℃ for 3h. After the reaction is complete, filter, wash, and dry to obtain aminated diatomaceous earth.

[0043] S2. Add 50g of alkali lignin to 200mL of 98% concentrated sulfuric acid and stir at 55℃ for 3h. Then slowly add 2kg of ice-water mixture (ice to water mass ratio of 1:1), filter, add sodium chloride to the filtrate and stir vigorously until no more precipitate is formed. Then centrifuge, wash and dry the solid product to obtain sulfonated lignin. Add 20g of chitosan to 1000g of 2% dilute acetic acid solution, stir to dissolve, then add 20g of sulfonated lignin, stir evenly, then add 90g of aminated diatomaceous earth and 40g of glutaraldehyde from step S1, adjust the pH to 3, and react at 70℃ for 5h. After the reaction is completed, filter, wash, dry and carbonize. The carbonization process is as follows: under nitrogen atmosphere, heat to 300℃ at a rate of 2℃ / min, hold for 3h, then heat to 600℃ at a rate of 4℃ / min, hold for 2h to obtain composite diatomaceous earth.

[0044] S3. Add 100g of composite diatomaceous earth from step S2 to 1L of ethanol aqueous solution (ethanol to water volume ratio of 9:1), then add 8g of γ-mercaptopropyltrimethoxysilane, and react at a constant temperature of 70℃ for 6h under a nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain mercapto-modified composite diatomaceous earth.

[0045] S4. Add 100g of thiolized composite diatomaceous earth from step S3 to 1L of mixed solvent (ethanol and DMF in a volume ratio of 8:2), then add 3.1g of 2,3-epoxypropyltrimethylammonium chloride and 0.5g of triethylamine. React at a constant temperature of 45℃ for 5h under a nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain functionalized composite diatomaceous earth.

[0046] S5. Add 100g of functionalized diatomaceous earth from step S4 to 900mL of ascorbic acid solution with a concentration of 5g / L, and sonicate for 20min. Under vigorous stirring (stirring speed of 600r / min), add 200mL of a mixed solution of copper nitrate and silver nitrate (concentration of copper nitrate is 5g / L, concentration of silver nitrate is 10g / L) dropwise over a time of 40min. After the addition is complete, react at a constant temperature of 55℃ for 5h under a nitrogen atmosphere. After the reaction is complete, filter, wash, and dry to obtain the air sterilization adsorbent material.

[0047] Example 3

[0048] A method for preparing an air sterilization adsorbent material includes the following steps:

[0049] S1. Add 150g of diatomaceous earth to 1L of 6mol / L hydrochloric acid solution and impregnate at 90℃ for 1h. After treatment, filter, wash, and dry, and calcine at 550℃ for 2h to obtain a solid product. Then add 100g of the solid product to 1L of ethanol aqueous solution (ethanol to water volume ratio of 9:1), followed by the addition of 12g of γ-aminopropyltriethoxysilane. Stir and react at 60℃ for 2h. After the reaction is complete, filter, wash, and dry to obtain aminated diatomaceous earth.

[0050] S2. Add 60g of alkali lignin to 300mL of 98% concentrated sulfuric acid and stir at 65℃ for 2h. Then slowly add 2kg of ice-water mixture (ice to water mass ratio of 1:1), filter, add sodium chloride to the filtrate and stir vigorously until no more precipitate is formed. Then centrifuge, wash and dry the solid product to obtain sulfonated lignin. Add 30g of chitosan to 1500g of 2% dilute acetic acid solution, stir to dissolve, then add 30g of sulfonated lignin, stir evenly, then add 100g of aminated diatomaceous earth and 50g of glutaraldehyde from step S1, adjust the pH to 5, and react at 80℃ for 4h. After the reaction is completed, filter, wash, dry and carbonize. The carbonization process is as follows: under nitrogen atmosphere, heat to 350℃ at a rate of 3℃ / min, hold for 2h, then heat to 650℃ at a rate of 5℃ / min, hold for 1h to obtain composite diatomaceous earth.

[0051] S3. Add 100g of composite diatomaceous earth from step S2 to 1L of ethanol aqueous solution (ethanol to water volume ratio of 9:1), then add 11g of γ-mercaptopropyltrimethoxysilane, and react at a constant temperature of 75℃ for 4h under a nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain mercapto-modified composite diatomaceous earth.

[0052] S4. Add 100g of thiolized composite diatomaceous earth from step S3 to 1L of mixed solvent (ethanol and DMF in a volume ratio of 8:2), then add 4.3g of 2,3-epoxypropyltrimethylammonium chloride and 1g of triethylamine. React at a constant temperature of 55℃ for 3h under a nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain functionalized composite diatomaceous earth.

[0053] S5. Add 100g of functionalized diatomaceous earth from step S4 to 1100mL of ascorbic acid solution with a concentration of 8g / L, and sonicate for 20min. Under vigorous stirring (stirring speed of 800r / min), add 300mL of a mixed solution of copper nitrate and silver nitrate (concentration of copper nitrate is 8g / L and concentration of silver nitrate is 15g / L) dropwise over a time of 50min. After the addition is complete, react at a constant temperature of 65℃ for 4h under a nitrogen atmosphere. After the reaction is complete, filter, wash, and dry to obtain the air sterilization adsorbent material.

[0054] Comparative Example 1

[0055] A method for preparing an air sterilization adsorbent material includes the following steps:

[0056] S1. 150g of diatomaceous earth was added to 1L of 5mol / L hydrochloric acid solution and impregnated at 85℃ for 1.5h. After treatment, the mixture was filtered, washed, and dried, and then calcined at 530℃ for 2.5h to obtain a solid product. Subsequently, 100g of the solid product was added to 1L of ethanol-water solution (ethanol to water volume ratio of 9:1), followed by the addition of 10g of γ-aminopropyltriethoxysilane. The mixture was stirred and reacted at 55℃ for 2.5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain aminated diatomaceous earth.

[0057] S2. Add 55g of alkali lignin to 250mL of 98% concentrated sulfuric acid and stir at 60℃ for 2.5h. Then slowly add 2kg of ice-water mixture (ice to water mass ratio of 1:1), filter, add sodium chloride to the filtrate and stir vigorously until no more precipitate is formed. Then centrifuge, wash and dry the solid product to obtain sulfonated lignin. Mix 25g of chitosan, 25g of sulfonated lignin and 95g of amino-modified diatomaceous earth from step S1, stir evenly, and carbonize. The carbonization process is as follows: under nitrogen atmosphere, heat to 330℃ at a rate of 2.5℃ / min and hold for 2.5h, then heat to 630℃ at a rate of 4.5℃ / min and hold for 1.5h to obtain composite diatomaceous earth.

[0058] S3. Add 100g of composite diatomaceous earth from step S2 to 1L of ethanol aqueous solution (ethanol to water volume ratio of 9:1), then add 10g of γ-mercaptopropyltrimethoxysilane, and react at a constant temperature of 72℃ for 5h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain mercapto-modified composite diatomaceous earth.

[0059] S4. Add 100g of thiolized composite diatomaceous earth from step S3 to 1L of mixed solvent (ethanol and DMF in a volume ratio of 8:2), then add 3.8g of 2,3-epoxypropyltrimethylammonium chloride and 0.8g of triethylamine. React at a constant temperature of 50℃ for 4h under a nitrogen atmosphere. After the reaction is complete, filter, wash and dry to obtain functionalized composite diatomaceous earth.

[0060] S5. Add 100g of functionalized diatomaceous earth from step S4 to 1000mL of ascorbic acid solution with a concentration of 7g / L, and sonicate for 20min. Under vigorous stirring (stirring speed of 700r / min), add 250mL of a mixed solution of copper nitrate and silver nitrate (concentration of copper nitrate is 7g / L, concentration of silver nitrate is 13g / L) dropwise over a time of 45min. After the addition is complete, react at a constant temperature of 60℃ for 4.5h under a nitrogen atmosphere. After the reaction is complete, filter, wash, and dry to obtain the air sterilization adsorbent material.

[0061] Compared with Example 1, the composite diatomaceous earth in this comparative example is obtained by physically mixing chitosan, sulfonated lignin, and aminated diatomaceous earth.

[0062] Comparative Example 2

[0063] A method for preparing an air sterilization adsorbent material includes the following steps:

[0064] S1. 150g of diatomaceous earth was added to 1L of 5mol / L hydrochloric acid solution and impregnated at 85℃ for 1.5h. After treatment, the mixture was filtered, washed, and dried, and then calcined at 530℃ for 2.5h to obtain a solid product. Subsequently, 100g of the solid product was added to 1L of ethanol-water solution (ethanol to water volume ratio of 9:1), followed by the addition of 10g of γ-aminopropyltriethoxysilane. The mixture was stirred and reacted at 55℃ for 2.5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain aminated diatomaceous earth.

[0065] S2. Add 55g of alkali lignin to 250mL of 98% concentrated sulfuric acid and stir at 60℃ for 2.5h. Then slowly add 2kg of an ice-water mixture (ice to water mass ratio of 1:1), filter, add sodium chloride to the filtrate and stir vigorously until no more precipitate forms. Then centrifuge, wash and dry the solid product to obtain sulfonated lignin. Add 25g of chitosan to 1300g of 2% dilute acetic acid solution and stir. After dissolving, add 25g of sulfonated lignin, stir evenly, then add 95g of aminated diatomaceous earth and 45g of glutaraldehyde from step S1, adjust the pH to 4, and react at 75℃ for 4.5h. After the reaction is complete, filter, wash, dry, and carbonize. The carbonization process is as follows: under a nitrogen atmosphere, heat to 330℃ at a rate of 2.5℃ / min, hold for 2.5h, then heat to 630℃ at a rate of 4.5℃ / min, and hold for 1.5h to obtain composite diatomaceous earth.

[0066] S3. Add 100g of composite diatomaceous earth from step S2 to 1L of ethanol aqueous solution (ethanol to water volume ratio of 9:1), then add 10g of γ-mercaptopropyltrimethoxysilane, and react at a constant temperature of 72℃ for 5h under nitrogen atmosphere. After the reaction is completed, filter, wash and dry to obtain mercapto-modified composite diatomaceous earth.

[0067] S4. Add 100g of thiolized composite diatomaceous earth from step S3 to 1000mL of ascorbic acid solution with a concentration of 7g / L, and ultrasonically disperse for 20min. Then, under vigorous stirring (stirring speed of 700r / min), add 250mL of a mixed solution of copper nitrate and silver nitrate (concentration of copper nitrate is 7g / L and concentration of silver nitrate is 13g / L) dropwise over a time of 45min. After the addition is complete, react at a constant temperature of 60℃ for 4.5h under a nitrogen atmosphere. After the reaction is complete, filter, wash, and dry to obtain the air sterilization adsorbent material.

[0068] Compared with Example 1, the air sterilization adsorbent material in this comparative example did not introduce 2,3-epoxypropyltrimethylammonium chloride.

[0069] Comparative Example 3

[0070] A method for preparing an air sterilization adsorbent material includes the following steps:

[0071] S1. 150g of diatomaceous earth was added to 1L of 5mol / L hydrochloric acid solution and impregnated at 85℃ for 1.5h. After treatment, the mixture was filtered, washed, and dried, and then calcined at 530℃ for 2.5h to obtain a solid product. Subsequently, 100g of the solid product was added to 1L of ethanol-water solution (ethanol to water volume ratio of 9:1), followed by the addition of 10g of γ-aminopropyltriethoxysilane. The mixture was stirred and reacted at 55℃ for 2.5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain aminated diatomaceous earth.

[0072] S2. Add 55g of alkali lignin to 250mL of 98% concentrated sulfuric acid and stir at 60℃ for 2.5h. Then slowly add 2kg of an ice-water mixture (ice to water mass ratio of 1:1), filter, add sodium chloride to the filtrate and stir vigorously until no more precipitate forms. Then centrifuge, wash and dry the solid product to obtain sulfonated lignin. Add 25g of chitosan to 1300g of 2% dilute acetic acid solution and stir. After dissolving, add 25g of sulfonated lignin, stir evenly, then add 95g of aminated diatomaceous earth and 45g of glutaraldehyde from step S1, adjust the pH to 4, and react at 75℃ for 4.5h. After the reaction is complete, filter, wash, dry, and carbonize. The carbonization process is as follows: under a nitrogen atmosphere, heat to 330℃ at a rate of 2.5℃ / min, hold for 2.5h, then heat to 630℃ at a rate of 4.5℃ / min, and hold for 1.5h to obtain composite diatomaceous earth.

[0073] S3. Add 100g of composite diatomaceous earth from step S2 to 1L of mixed solvent (ethanol and DMF in a volume ratio of 8:2), then add 3.8g of 2,3-epoxypropyltrimethylammonium chloride, stir at 50℃ for 4h, filter, wash and dry after the reaction is complete to obtain functionalized composite diatomaceous earth.

[0074] S4. Add 100g of functionalized diatomaceous earth from step S3 to 1000mL of ascorbic acid solution with a concentration of 7g / L, and sonicate for 20min. Under vigorous stirring (stirring speed of 700r / min), add 250mL of a mixed solution of copper nitrate and silver nitrate (concentration of copper nitrate is 7g / L and concentration of silver nitrate is 13g / L) dropwise over a time of 45min. After the addition is complete, react at a constant temperature of 60℃ for 4.5h under a nitrogen atmosphere. After the reaction is complete, filter, wash, and dry to obtain the air sterilization adsorbent material.

[0075] Compared to Example 1, the air sterilization adsorbent material in this comparative example did not introduce γ-mercaptopropyltrimethoxysilane.

[0076] The air sterilization adsorbent materials prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests. The PM2.5 adsorption rate was tested as follows: Standard cigarette smoke was used as the PM2.5 source. The air was filtered through a fan and test pipe, using a solution containing 0.5 mg / m³ of PM2.5. 3 The experimental gas containing PM2.5 particles was flowed at a flow rate of 0.5 m / s through a filter filled with the test adsorbent material, with a filter thickness of 0.1 m, under conditions of temperature 23±1℃ and relative humidity 50±5%RH. Sampling ports were set at the upstream and downstream of the filter, and the particle concentration was measured simultaneously using two laser dust meters to determine the adsorption rate. The antibacterial rate was tested according to GB / T21510-2024 "Test Method for Antibacterial Properties of Nano-Inorganic Materials", with Escherichia coli as the test species. The cyclic test was as follows: 5 g of material was placed in a sealed container, and a gas containing 0.5 mg / m³ of PM2.5 was introduced. 3 The experimental gas containing PM2.5 particles and air with 90% RH was adsorbed for 1 hour, followed by immersion in a solution containing 10 7 The material was cultured in sterile physiological saline at CFU / mL for 2 hours with shaking. After filtration, the material was washed with sterile water and then twice with anhydrous ethanol. It was then vacuum dried at 60°C to obtain the regenerated adsorbent material, thus completing one "adsorption-regeneration" cycle. The antibacterial rate was tested after 20 cycles. The test results are shown in Table 1 below.

[0077] Table 1

[0078]

[0079] As can be seen from Table 1 above, the air sterilization adsorbent material prepared by the present invention has good adsorption rate and antibacterial rate, as well as long-lasting antibacterial rate and stability, and has good application prospects.

[0080] The above description is a further detailed explanation of the present invention in conjunction with specific implementation examples. It should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the protection scope of the present invention.

[0081] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an air sterilizing adsorbing material, characterized by, The method comprises the following steps: S1, adding alkali lignin into concentrated sulfuric acid, constant temperature stirring to obtain sulfonated lignin; adding chitosan into dilute acetic acid solution, stirring and dissolving, then adding sulfonated lignin, stirring uniformly, then adding aminated diatomite and glutaraldehyde, heating reaction, filtering, washing, drying and carbonizing after the reaction to obtain composite diatomite; S2, adding the composite diatomite into ethanol aqueous solution, then adding γ-mercaptopropyl trimethoxysilane, constant temperature reaction under nitrogen atmosphere, and obtaining mercapto-functionalized composite diatomite after the reaction; S3, adding the mercapto-functionalized composite diatomite into mixed solvent, then adding 2,3-epoxypropyl trimethyl ammonium chloride and triethylamine, constant temperature reaction under nitrogen atmosphere, and obtaining functionalized composite diatomite after the reaction; S4, adding the functionalized diatomite into ascorbic acid solution, ultrasonic dispersion, adding mixed solution of copper nitrate and silver nitrate dropwise under vigorous stirring, constant temperature reaction under nitrogen atmosphere after dropwise addition, and obtaining air sterilization adsorption material after the reaction. In step S1, the mass ratio of alkali lignin and concentrated sulfuric acid is 50-60:200-300, the temperature of constant temperature stirring is 55-65℃, and the time is 2-3h; the mass ratio of chitosan, dilute acetic acid solution, sulfonated lignin, aminated diatomite and glutaraldehyde is 20-30:1000-1500:20-30:90-100:40-50, the temperature of heating reaction is 70-80℃, the time is 4-5h, and the carbonization process is as follows: heating to 300-350℃ at a rate of 2-3℃ / min under nitrogen atmosphere, keeping for 2-3h, then heating to 600-650℃ at a rate of 4-5℃ / min, keeping for 1-2h.

2. The production method according to claim 1, characterized by, In step S1, the preparation method of aminated diatomite is as follows: adding diatomite into hydrochloric acid solution, impregnation treatment, filtering, washing, drying and calcination after the treatment, then adding solid product into ethanol aqueous solution, then adding γ-aminopropyl triethoxysilane, stirring reaction, and obtaining the product after filtering, washing and drying.

3. The preparation method according to claim 2, characterized in that, The concentration of hydrochloric acid is 4-6mol / L, the temperature of impregnation treatment is 80-90℃, the time is 1-2h, the temperature of calcination is 500-550℃, and the time is 2-3h; the mass ratio of solid product and γ-aminopropyl triethoxysilane is 100:8-12, and the temperature of stirring reaction is 50-60℃, and the time is 2-3h.

4. The method of claim 1, wherein, In step S2, the mass ratio of composite diatomite and γ-mercaptopropyl trimethoxysilane is 100:8-11, and the temperature of constant temperature reaction is 70-75℃, and the time is 4-6h.

5. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of mercapto-functionalized composite diatomite, 2,3-epoxypropyl trimethyl ammonium chloride and triethylamine is 100:3.1-4.3:0.5-1, the temperature of constant temperature reaction is 45-55℃, and the time is 3-5h.

6. The method of claim 1, wherein, The concentration of the ascorbic acid solution in step S4 is 5-8 g / L, the concentration of copper nitrate in the mixed solution is 5-8 g / L, and the concentration of silver nitrate is 10-15 g / L.

7. The preparation method according to claim 1, characterized in that, The mass-volume ratio of the functionalized diatomite, the ascorbic acid solution and the mixed solution in step S4 is 100 g: 900-1100 mL: 200-300 mL, the temperature of the constant temperature reaction is 55-65 °C, and the time is 4-5 h.

8. The air sterilization adsorption material prepared by the method of any one of claims 1-7.

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