Composite material as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of a composite material. The preparation method comprises the following steps: (1) pretreating diatomite; (2) preparation of CuAl / LDH-DE (Layered Double Hydroxide); (3) preparing EDTA (Ethylene Diamine Tetraacetic Acid) / TP-CuAl / LDH-D; and (4) preparing the composite material. The invention also discloses the composite material and application of the composite material in an acarus killing material.

Description

Technical Field

[0001] The present invention belongs to the technical field of acaricides, and specifically relates to a long-acting slow-release nanomaterial with a 3D bionic structure, a green preparation method thereof, and uses thereof. Background Art

[0002] Dust mites are one of the mite species closely related to human health, belonging to the family Acaridae, subclass Acari, class Arachnida, phylum Arthropoda. They are extremely small in size and usually survive in environments with a temperature of 30 °C and a humidity of over 65%. They are extremely easy to breed in fabric products such as mattresses, pillows, carpets, sofas, curtains, and clothes, and reproduce at an extremely fast rate. Research shows that under suitable environmental conditions, a single female dust mite can lay 60 - 100 eggs during its life cycle, and a common mattress may contain millions of dust mites. Even with regular cleaning, it is still difficult to completely eliminate dust mites and their allergens. The corpses, secretions, and excreta of dust mites all contain strong sensitizing components, which can cause various respiratory and skin allergic diseases. It has been found that allergens (such as Der p1, Der p2, etc.) in dust mite feces and surface proteins are the main factors causing allergies. Their particles are small (<10 μm), can float in the air for a long time, and are easily inhaled by the human body, which can easily induce allergic reactions. Dust mite allergy is one of the main causes of asthma, allergic rhinitis, and allergic conjunctivitis, manifested as symptoms such as nasal congestion, sneezing, runny nose, itchy eyes, coughing, airway inflammation, etc. In severe cases, it may cause difficulty in breathing and even endanger life. In addition, dust mite allergy can also cause skin diseases such as allergic dermatitis and atopic dermatitis, presenting symptoms such as skin redness, itching, and papules, greatly affecting the quality of life of patients.

[0003] Currently, the main prevention and control measures for dust mites on the market include physical, chemical, and biological technologies, etc. Physical methods such as high-temperature washing, ultraviolet irradiation, and dust suction to remove mites can reduce the number of mites to a certain extent, but it is difficult to completely remove dust mites and their allergens, and the action time is limited; chemical methods such as acaricide sprays and Chinese herbal acaricides can inhibit the growth of mites in the short term, but they are prone to chemical residues, affecting human health, and there are problems such as fast odor volatilization and short-lasting effects; biological methods such as probiotic acaricide removal are still in the research stage, and actual applications still need further verification. Generally speaking, the existing acaricide removal means mainly passively remove mites, and cannot achieve active capture and long-term killing, and the acaricide removal effect is limited. Summary of the Invention

[0004] In order to overcome the above deficiencies of the prior art, the present invention provides a long-acting slow-release nano acaricide composite material with a 3D bionic structure and a green preparation method thereof. The present invention is achieved through the following technical solutions: Based on 3D bionic diatomite modified CuAl-LDH (layered double hydroxide), and through functionalization modification, the dual functions of efficient bionic trapping and long-term killing are realized, thereby improving the acaricide removal efficiency.

[0005] The technical solution of the present invention is as follows:

[0006] The first aspect of the present invention discloses a preparation method of a composite material, comprising the following steps:

[0007] (1) Pretreatment of diatomite: adding disc-shaped diatomite to a NaOH solution; mixing, separating, washing at a certain temperature, and drying at a certain temperature to obtain pretreated diatomite;

[0008] (2) Preparation of CuAl / LDH-DE: dissolving a copper salt and an aluminum salt in water to form solution A, dissolving NaOH in water to form solution B, and dissolving Na2CO3 in water to form solution C; dropping the pretreated diatomite, solution A, and B into solution C simultaneously, and maintaining the pH value of the mixed solution at 9.0 - 10.0; aging the obtained mixed solution at a certain temperature for a period of time, separating, washing, and drying in vacuum to obtain a material denoted as CuAl / LDH-DE;

[0009] (3) Preparation of EDTA / TP-CuAl / LDH-D: putting the CuAl / LDH-DE sample into a mixed solution containing ethylenediaminetetraacetic acid and tea polyphenols, and adjusting the pH value to 8.5 - 9.5; then maintaining at a certain temperature for a period of time; separating, washing, and drying to obtain a material denoted as EDTA / TP-CuAl / LDH-DE;

[0010] (4) Preparation of the composite material: impregnating EDTA / TP-CuAl / LDH-DE in a silver salt solution and maintaining for a period of time, then separating, washing, and drying in vacuum to obtain a material denoted as Ag@EDTA / TP-CuAl / LDH-DE; which is the composite material described above.

[0011] Preferably, in step (1), disc-shaped diatomite with a particle size of 20 - 25 μm and a pore size of 150 - 250 nm is added to a 5 - 7 wt% NaOH solution to ensure that the mass fraction of diatomite is 3 - 5 wt%; after vigorously stirring the mixture at 50 - 70 °C for more than 1 h, the mixture is centrifuged; then, the precipitate is washed with distilled water to be neutral; finally, the washed precipitate is dried in an oven at 100 - 120 °C for more than 10 h.

[0012] Preferably, the addition amounts of the copper salt and the aluminum salt in step (2) are in a molar ratio of (1-4):1; the mixed solution is aged at 50-70 °C for more than 10 hours; the copper salt or the aluminum salt is a nitrate. Specifically: 0.01-0.04 mol of Cu(NO3)2·3H2O and 0.01 mol of A(NO3)3·9H2O are dissolved in 18 mL of deionized water to prepare a mixed solution A, 0.045 mol of NaOH is dissolved in 30 mL of deionized water to form solution B, and 0.01 mol of Na2CO3 is dissolved in 180 mL of deionized water to form solution C; subsequently, under constant-speed stirring, 100 mg of the pretreated diatomite, solution A and B in step (1) are simultaneously dropped into solution C, while controlling the addition rates of solution A and B and maintaining the pH at about 9.5, and monitoring the pH value; the obtained mixed solution is aged at about 60 °C in a water bath for more than 12 hours, then the product is collected by centrifugation, washed 5-10 times with deionized water, and finally dried overnight in a vacuum drying oven at about 60 °C to obtain a material denoted as CuAl / LDH-DE.

[0013] Preferably, the addition amounts of ethylenediaminetetraacetic acid and tea polyphenols in step (3) are in a molar ratio of 10:(1-10); the pH value is adjusted with a NaOH solution; it is maintained at a temperature of 60-70 °C for more than 10 hours; the obtained product is thoroughly washed with ethanol to obtain EDTA / TP-CuAl / LDH-DE. Specifically: CuAl / LDH-DE is placed in a 100 mL aqueous solution of deionized water containing 0.1 M ethylenediaminetetraacetic acid (EDTA) and 0.01-0.1 M tea polyphenols; the pH value of the solution is adjusted to about 9 by adding 0.1 M NaOH; then the obtained solution is placed in a hydrothermal reactor and maintained at a temperature of about 65 °C for about 12 hours; after the reaction is completed, the obtained sample is thoroughly washed with absolute ethanol and then dried for use; the obtained material is denoted as EDTA / TP-CuAl / LDH-DE.

[0014] Preferably, the step of impregnating EDTA / TP-CuAl / LDH-DE in a silver salt solution and maintaining for a period of time for Ag+ adsorption in step (4) needs to be carried out under light-shielded conditions; washed with water to remove free Ag+, and vacuum dried at 50-70 °C; thus obtaining the composite material. Specifically: Under light-shielded conditions, 100 mg of EDTA / TP-CuAl / LDH-DE is impregnated in 100 mL of 0.1-0.4 M AgNO3 solution, and continuously stirred or left standing slightly in the dark for about 2 hours to ensure that Ag+ is fully adsorbed on the surface and between the layers of the material; then centrifuged, washed with deionized water no less than 3 times to remove free Ag+, and after vacuum drying at 60 °C, the obtained material is denoted as Ag@EDTA / TP-CuAl / LDH-DE; which is the composite material described above.

[0015] The second aspect of the present invention discloses a composite material prepared by the described preparation method.

[0016] The third aspect of the present invention discloses the use of the described composite material as a mite-removing material.

[0017] Preferably, the composite material is prepared into composite particles, and then a multi-layer gradient filtration structure is prepared.

[0018] Preferably, the preparation steps of the composite particles are as follows: treating activated carbon particles with nitric acid, washing with water until neutral, and then drying; then mixing them with the composite material in a certain mass ratio, adding a binder to uniformly load the composite material in the pores and on the surface of the activated carbon; and then drying under vacuum to obtain the composite particles.

[0019] Preferably, the multi-layer gradient filtration structure has three layers, and its preparation steps are as follows: filling the composite particles into a mold, and preparing a porous filter element matrix under certain temperature and pressure; using the porous filter element matrix as the middle layer, with an outer layer of a polypropylene melt-blown non-woven fabric layer of a certain thickness and an inner layer of an electrospun nanofiber membrane; using epoxy resin glue to bond the three layers of materials and curing for a certain period of time to obtain a three-layer gradient filtration structure; the obtained three-layer gradient filtration structure can be encapsulated in an aluminum mesh frame to enhance mechanical strength and air permeability.

[0020] The specific preparation steps of the three-layer gradient filtration structure are to first prepare composite particles and then prepare the three-layer gradient filtration structure. The preparation steps of the composite particles are as follows: immersing activated carbon particles with a particle size of 1-2 mm in a 5 wt% nitric acid solution and ultrasonically treating for 30 minutes to remove surface impurities and ash, washing with deionized water until neutral, and drying at about 110 °C for about 12 hours to complete the pretreatment. Then mixing the pretreated activated carbon with the composite material in a mass ratio of 3:1, adding a 5 wt% polyvinyl alcohol (PVA) solution as a binder, stirring at 60 °C for 2 hours to uniformly load the nanomaterial in the pores and on the surface of the activated carbon, centrifuging and then drying under vacuum at 60 °C for 12 hours to obtain the composite particles.

[0021] The preparation steps of the three-layer gradient filtration structure are adopted; the obtained composite particles are filled into a mold (size 20cm×20cm×1cm), hot-pressed at 10MPa pressure and 80℃ for 30 minutes, and the prepared porous filter element matrix is ​​used as the second layer (filling density 0.8g / cm3, thickness 10mm); the first layer is polypropylene melt-blown non-woven fabric (thickness 2mm), which is used to intercept large particles (>10μm); the second layer is a composite particle filling layer, which is loaded with composite materials and activated carbon to achieve adsorption, sterilization and mite removal functions; the third layer is an electrospun nanofiber membrane (PET / PA6, pore size 0.1μm), which is used to intercept PM2.5 and residual allergens. The three layers of materials are bonded with high-temperature resistant epoxy resin glue and cured at 60℃ for 2 hours. Finally, the aluminum mesh frame is encapsulated to enhance mechanical strength and air permeability.

[0022] Beneficial effects of the present invention:

[0023] The composite material of the present invention enhances the material's loading capacity and long-term sustained-release capacity by modifying CuAl-LDH (layered double hydroxide) through 3D bionic diatomite; combined with the antibacterial and anti-mite effect of silver ions (Ag+), the durability and efficient mite killing ability of the composite material are improved. Diatomite can be used for physical adsorption of mites and their allergens due to its rich pore structure and large specific surface area. However, when diatomite is used alone, the adsorption capacity is limited and the long-term antibacterial function cannot be achieved. Therefore, the present invention enhances the material's loading capacity by modifying CuAl-LDH on 3D bionic diatomite, while providing a large amount of hydroxyl groups and interlayer space, improving the feasibility of chemical modification, and enhancing the sustained-release capacity of the material, so that the active ingredients can be released for a long time to avoid failure in a short time.

[0024] The preparation method of the present invention adopts an environmentally friendly and safe preparation process, and reduces chemical residues through EDTA modification and tea polyphenol reduction of silver ions; combined with physical adsorption, chemical inhibition and biological trapping (adding mite pheromone analogs, such as fatty acid derivatives), a comprehensive prevention and control of mite removal is formed. The preparation method of the present invention enhances the stability of metal ions by inserting ethylenediaminetetraacetic acid (EDTA) between CuAl-LDH layers, and promotes the controlled release of silver ions (Ag+), providing a broad-spectrum antibacterial and mite-inhibiting effect; silver ions have a significant bactericidal effect, while reducing toxic chemical residues, and are more environmentally friendly than traditional mite removers; tea polyphenols are introduced as a reducing agent, which can reduce Ag+ to Ag elemental substance, achieve gentle and safe conversion, and give the material antioxidant function, which can effectively prevent textiles from aging, extend the service life of the material, and make it more suitable for fabric products that are in long-term contact with the human body, such as mattresses, pillow cores, sofas, and car seat covers; the surface of the composite material can also be grafted with mite pheromone analogs (such as fatty acid derivatives) for bionic trapping, simulating the chemical signals of mites, and actively attracting mites to approach; improving the efficiency of mite removal.

[0025] The use of the composite material of the present invention as a mite-removing material breaks through the passive mode of traditional mite-removing means, enabling the mite-removing material to actively trap mites and achieve efficient physical adsorption. Through multiple mechanisms of physical adsorption, chemical inhibition, and bionic trapping, the mite-removing efficiency of this material is significantly improved, solving the deficiencies of the prior art. The composite material of the present invention can not only inhibit the reproduction of mites in a long-term and continuous manner but also has the advantages of environmental protection and safety, avoiding the problem of chemical residues, and is particularly suitable for textiles that are in long-term contact with the human body, such as mattresses, pillows, sofas, curtains, etc. The layered structure of CuAl-LDH enhances the loading capacity of the material, enabling the sustainable release of silver ions, improving the persistence of antibacterial and mite-inhibiting effects and the long-term slow-release of mite inhibition; the synergistic effect of Ag+ and tea polyphenols achieves efficient mite killing and avoids the problem of chemical residues, being environmentally friendly and safe, circumventing the toxicity risks of traditional chemical miticides, and being more friendly to the human body and the environment; the antioxidant ability of tea polyphenols effectively prevents the aging of textiles, protecting and enhancing the durability of textiles.

[0026] The composite material of the present invention has a mite-killing rate of 15.75% in 7 days and an antibacterial rate > 95%. Description of the Drawings

[0027] Figure 1 Scanning electron micrographs of the composite materials of Examples 1-4.

[0028] Figure 2 Mite-removing effect diagrams of the composite materials of Examples 1-4.

[0029] Figure 3 Scanning electron micrographs of the composite materials of Examples 1-4 after mite removal.

[0030] Figure 4 Bacteriostatic rate diagrams of the composite materials of Examples 1-4.

[0031] Figure 5 EDS diagrams of the composite material of Example 3. Detailed Description of the Invention

[0032] The technical solutions of the present invention will be described in detail below in conjunction with the examples. The following examples are only used to illustrate the present invention and should not be construed as limiting the protection scope of the present invention. For those not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0033] Example 1: Preparation of the composite material and its use as a mite-removing material.

[0034] (1) Pretreatment of diatomite

[0035] Sieve the disc-shaped diatoms to obtain 100 mg of diatoms with a uniform particle size of 20 μm, a pore size of 200 nm, and a uniform pore distribution. Add the sieved diatomaceous earth to a 6 wt% NaOH solution to ensure that the mass fraction of the diatomaceous earth is 4 wt%. After vigorously stirring the mixture at 60 °C for 1 h, centrifuge the mixture and retain the precipitate; then, wash the precipitate with distilled water until it is neutral; finally, dry the washed precipitate in an oven at 110 °C for 10 h.

[0036] (2) Preparation of CuAl / LDH-DE:

[0037] Using the coprecipitation method, dissolve 0.01 mol of Cu(NO3)2·3H2O and 0.01 mol of Al(NO3)3·9H2O in 18 mL of deionized water to prepare a mixed metal solution (solution A), dissolve 0.045 mol of NaOH in 30 mL of deionized water (solution B), and dissolve 0.01 mol of Na2CO3 in 180 mL of deionized water (solution C). Subsequently, under constant-speed stirring, add 100 mg of diatomaceous earth obtained in step (1), solution A, and B to solution C simultaneously, and control the addition rates of solution A and B to maintain the pH at 9.5, and monitor the pH value. The resulting mixed solution is aged at 60 °C in a water bath for 12 hours, then the product is collected by centrifugation, washed 5 times with deionized water, and finally dried overnight in a vacuum drying oven at 60 °C to obtain the composite material labeled CuAl / LDH-DE.

[0038] (3) Preparation of EDTA / TP-CuAl / LDH-DE:

[0039] Place the CuAl / LDH-DE sample in 100 mL of deionized aqueous solution containing 0.1 M ethylenediaminetetraacetic acid (EDTA) and 0.02 M tea polyphenols. Adjust the pH value of the solution to 9 by adding 0.1 M NaOH. Then place the resulting solution in a hydrothermal reactor and maintain it at a temperature of 65 °C for 12 hours. After the reaction is completed, the obtained sample is thoroughly washed with ethanol and dried for use, and the resulting composite material is labeled EDTA / TP-CuAl / LDH-DE.

[0040] (4) Preparation of Ag@EDTA / TP-CuAl / LDH-DE:

[0041] Under light-shielded conditions, immerse 100 mg of EDTA / TP-CuAl / LDH-DE in 0.1 M AgNO3 solution (100 mL), and continuously stir or let it stand for 2 hours under light shielding to ensure that Ag+ is fully adsorbed on the surface and between the layers of the material. Subsequently, centrifuge and separate the material, wash it 3 times with deionized water to remove free Ag+, and after vacuum drying at 60 °C, it is denoted as Ag@EDTA / TP-CuAl / LDH-DE; that is, the composite material.

[0042] (5) Use of preparing the composite material into composite particles and then preparing a multi-layer gradient filtration structure for use as a mite removal material. The preparation steps of the composite particles are as follows: Immerse granular activated carbon (particle size 1-2 mm) in a 5% nitric acid solution and ultrasonically treat for 30 minutes to remove surface impurities and ash. Wash with deionized water until neutral and then dry at 110 °C for 12 hours to complete the pretreatment. Subsequently, mix the pretreated activated carbon with the Ag@EDTA / TP-CuAl / LDH-DE nanomaterial in a mass ratio of 3:1, add a 5 wt% polyvinyl alcohol (PVA) solution as a binder, and stir at 60 °C for 2 hours to uniformly load the nanomaterial in the pores and on the surface of the activated carbon. After centrifugal separation, vacuum dry at 60 °C for 12 hours to obtain composite particles. Preparation of the three-layer gradient filtration structure: Fill the obtained composite particles into a mold (size 20 cm × 20 cm × 1 cm), hot press at 10 MPa pressure and 80 °C for 30 minutes. The prepared porous filter element matrix is used as the second layer (filling density 0.8 g / cm3, thickness 10 mm); the first layer is a polypropylene melt-blown non-woven fabric (thickness 2 mm) for intercepting large particles (>10 μm); the second layer is a composite particle filling layer loaded with the composite material and activated carbon to achieve the functions of adsorption, sterilization, and mite removal; the third layer is an electrospun nanofiber membrane (PET / PA6, pore size 0.1 μm) for intercepting PM2.5 and residual allergens. Bond the three layers of materials with a high-temperature resistant epoxy resin adhesive and cure at 60 °C for 2 hours. Finally, encapsulate an aluminum mesh frame to enhance mechanical strength and air permeability.

[0043] Figure 1 (a-a2) is the scanning electron microscope image of the Ag@EDTA / TP-CuAl / LDH-DE composite material obtained in this example; it can be seen from the figure that the material morphology is relatively rough, the combination between particles is relatively loose, there is a certain distribution of nanoparticles on the surface, but the pore structure is not obvious. Figure 2 (a-a1) is the mite removal effect diagram of the Ag@EDTA / TP-CuAl / LDH-DE composite material obtained in this example, which is a microscope image after 14 days of mite killing; it can be seen from the figure that there are still many surviving individuals of mites, and some mites show a slightly shriveled state. Figure 3 (a-a1) is the scanning electron microscope image of the Ag@EDTA / TP-CuAl / LDH-DE composite material after 14 days of mite removal in this example. It can be seen from the figure that the mites show a slightly shriveled phenomenon, but no large-scale damage is observed. Figure 4Antibacterial rate graph of the composite materials obtained in Examples 1-4; It can be seen from the figure that the antibacterial rate of the Ag@EDTA / TP-CuAl / LDH-DE composite material obtained in this example against Escherichia coli after 40 days is 87.82%, and the antibacterial rate against Staphylococcus aureus after 40 days is 86.82%. Table 1 shows the comparison of the killing rates of the mite-killing bags and commercially available mite-killing bags against Dermatophagoides farinae. The killing rate of the mite-killing bag in this example is 100.0±0 on the first day of action, 3.4±1.9 on the 7th day, and 0±0 on the 14th day. Table 2 shows the calculation indexes of the mite-killing bag. The moisture content of the mite-killing bag in this example is 8%, the powder falling rate is 1%, and the compressive strength is 82 N / granule.

[0044] Example 2: Preparation of composite materials and their use as mite-killing materials.

[0045] (1) Pretreatment of diatomite, the same as in Example 1.

[0046] (2) Preparation of CuAl / LDH-DE:

[0047] Using the co-precipitation method, 0.02 mol of Cu(NO3)2·3H2O and 0.01 mol of A(NO3)3·9H2O are dissolved in 18 mL of deionized water to prepare a mixed metal solution (Solution A). 0.045 mol of NaOH is dissolved in 30 mL of deionized water (Solution B), and 0.01 mol of Na2CO3 is dissolved in 180 mL of deionized water (Solution C). Subsequently, under constant-speed stirring, 100 mg of diatomite, Solution A, and B are simultaneously added dropwise to Solution C, while controlling the addition rates of Solution A and B to maintain the pH at 9.5 and monitoring the pH value. The resulting mixed solution is aged at 60 °C in a water bath for 12 hours, then the product is collected by centrifugation, washed 5 times with deionized water, and finally dried overnight in a vacuum drying oven at 60 °C. The obtained composite material is labeled as CuAl / LDH-DE.

[0048] (3) Preparation of CuAl / LDH-DE material:

[0049] The CuAl / LDH-DE sample is placed in a 100 mL aqueous solution of deionized water containing 0.1 M ethylenediaminetetraacetic acid (EDTA) and 0.04 M tea polyphenols. The pH value of the solution is adjusted to 9 by adding 0.1 M NaOH. Then the resulting solution is placed in a hydrothermal reactor and maintained at a temperature of 65 °C for 12 hours. After the reaction, the obtained sample is thoroughly washed with ethanol and dried for use. The obtained composite material is labeled as EDTA / TP-CuAl / LDH-DE.

[0050] (4) Preparation of Ag@EDTA / TP-CuAl / LDH-DE:

[0051] Under light - avoiding conditions, 100 mg of the EDTA / TP - CuAl / LDH - DE composite material was impregnated in a 0.2 M AgNO₃ solution (100 mL), and gently stirred or left standing for 2 hours while avoiding light to ensure that Ag⁺ was fully adsorbed on the surface and between the layers of the material. Subsequently, the material was separated by centrifugation, washed 3 times with deionized water to remove free Ag⁺, and dried in vacuo at 60 °C, denoted as Ag@EDTA / TP - CuAl / LDH - DE; this is the composite material described above.

[0052] (5) Use of the composite material to prepare composite particles and then prepare a multi - layer gradient filtration structure for use as a mite - removing material. The same as in Example 1.

[0053] Figure (b - b2) is a scanning electron micrograph of the Ag@EDTA / TP - CuAl / LDH - DE composite material obtained in this example, similar to group (a); however, the particle distribution is more uniform, there are more surface - modified nanoparticles, and finer nanoparticles can be observed filling the surface of the material, and the overall structure is still relatively loose. Figure 2 (a - a1) is the mite - removing effect diagram of the Ag@EDTA / TP - CuAl / LDH - DE composite material obtained in this example, which is a micrograph after 14 days of killing mites; it can be seen from the figure that some complete individuals can still be observed, and there are certain degrees of damage on the surface of the dead mites. Figure 3 (a - a1) is a scanning electron micrograph of the Ag@EDTA / TP - CuAl / LDH - DE composite material after 14 days of mite - removing in this example. It can be seen from the figure that the mite individuals show collapse and body surface damage, indicating that the material has a certain destructive effect on mites. Figure 4 It is the antibacterial rate diagram of the composite materials obtained in Examples 1 - 4; it can be seen from the figure that the antibacterial rate of the Ag@EDTA / TP - CuAl / LDH - DE composite material obtained in this example against Escherichia coli after 40 days is 91.55%, and the antibacterial rate against Staphylococcus aureus after 40 days is 98.55%. Table 1 shows the comparison of the killing rates of the mite - removing bags and commercially available mite - removing bags against Dermatophagoides farinae. The killing rate of the mite - removing bag in this example against Dermatophagoides farinae is 100.0 ± 0 at 1 day, 7.6 ± 3.2 at 7 days, and 0 ± 0 at 14 days. Table 2 shows the calculation indexes of the mite - removing bag. The moisture content of the mite - removing bag in this example is 8%, the powder - falling rate is 1%, and the compressive strength is 86 N / particle.

[0054] Example 3: Preparation of the composite material and its use as a mite - removing material.

[0055] (1) Pretreatment of diatomite, the same as in Example 1.

[0056] (2) Preparation of CuAl / LDH - DE:

[0057] Using the co-precipitation method, 0.03 mol of Cu(NO3)2·3H2O and 0.01 mol of A(NO3)3·9H2O were dissolved in 18 mL of deionized water to prepare a mixed metal solution (Solution A). 0.045 mol of NaOH was dissolved in 30 mL of deionized water (Solution B), and 0.01 mol of Na2CO3 was dissolved in 180 mL of deionized water (Solution C). Subsequently, under constant-speed stirring, 100 mg of diatomite, Solution A, and B were simultaneously added dropwise to Solution C, while controlling the addition rates of Solution A and B to maintain the pH at 9.5 and monitoring the pH value. The resulting mixed solution was aged at 60 °C in a water bath for 12 hours, then the product was collected by centrifugation, washed 5 times with deionized water, and finally dried overnight in a vacuum drying oven at 60 °C to obtain a composite material labeled CuAl / LDH-DE.

[0058] (3) Preparation of CuAl / LDH-DE material:

[0059] The CuAl / LDH-DE sample was placed in 100 mL of deionized aqueous solution containing 0.1 M ethylenediaminetetraacetic acid (EDTA) and 0.06 M tea polyphenols. The pH value of the solution was adjusted to 9 by adding 0.1 M NaOH. Then the resulting solution was placed in a hydrothermal reactor and maintained at a temperature of 65 °C for 12 hours. After the reaction, the obtained sample was thoroughly washed with ethanol and dried for use, and the resulting composite material was labeled EDTA / TP-CuAl / LDH-DE.

[0060] (4) Preparation of Ag@EDTA / TP-CuAl / LDH-DE:

[0061] Under light-shielded conditions, 100 mg of the EDTA / TP-CuAl / LDH-DE composite material was impregnated in 0.3 M AgNO3 solution (100 mL), and gently stirred or left standing in the dark for 2 hours to ensure that Ag+ was fully adsorbed on the surface and between the layers of the material. Subsequently, the material was separated by centrifugation, washed 3 times with deionized water to remove free Ag+, and after vacuum drying at 60 °C, it was labeled Ag@EDTA / TP-CuAl / LDH-DE; namely, the said composite material.

[0062] (5) Use of the composite material to prepare composite particles and then prepare a multi-layer gradient filtration structure for use as a mite removal material; same as Example 1.

[0063] Figure 1 (c-c2) Scanning electron micrograph of the Ag@EDTA / TP-CuAl / LDH-DE composite material obtained in this example; it can be seen from the figure that the particle morphology of the material is regular, presenting a spherical structure, and the surface is relatively dense, with uniformly distributed nanoparticles and a relatively smooth surface. Figure 2(c-c1) is the mite-killing effect diagram of the Ag@EDTA / TP-CuAl / LDH-DE composite material obtained in this example, which is a microscope image 14 days after killing mites; as can be seen from the figure, the mites are almost dead, and the individuals are significantly shriveled and damaged, indicating that the material can effectively penetrate the surface layer of mites and kill them. Figure 3 (c-c1) is the scanning electron microscope image of the Ag@EDTA / TP-CuAl / LDH-DE composite material obtained in this example 14 days after killing mites. As can be seen from the figure, the mite individuals show severe shriveling and cracking, and even the outer shells of some mites are completely disintegrated, indicating that the material has a strong destructive effect on mites. Figure 4 It is the antibacterial rate diagram of the composite materials obtained in Examples 1-4; as can be seen from the figure, the antibacterial rate of the Ag@EDTA / TP-CuAl / LDH-DE composite material obtained in this example against Escherichia coli after 40 days is 98.55%, and the antibacterial rate against Staphylococcus aureus after 40 days is 97.21%. Table 1 shows the comparison of the killing rates of the mite-killing package and the commercially available mite-killing package against Dermatophagoides farinae. The killing rate of the mite-killing package in this example against Dermatophagoides farinae is 100.0±0 at 1 day, 15.75±1.3 at 7 days, and 0±0 at 14 days. Table 2 shows the calculation indexes of the mite-killing package. The moisture content of the mite-killing package in this example is 8%, the powder falling rate is 1%, and the compressive strength is 90 N / granule. Figure 5 It is the EDS diagram of the composite material in this example. It can be seen that the Si, O, Cu, Al, and Ag elements are evenly distributed, confirming the successful synthesis of the material.

[0064] Example 4: Preparation of the composite material and its use as a mite-killing material.

[0065] (1) Pretreatment of diatomite is the same as that in Example 1.

[0066] (2) Preparation of CuAl / LDH-DE:

[0067] Using the co-precipitation method, 0.04 mol of Cu(NO3)2·3H2O and 0.01 mol of A(NO3)3·9H2O are dissolved in 18 mL of deionized water to prepare a mixed metal solution (solution A). 0.045 mol of NaOH is dissolved in 30 mL of deionized water (solution B), and 0.01 mol of Na2CO3 is dissolved in 180 mL of deionized water (solution C). Subsequently, under constant-speed stirring, 100 mg of diatomite, solution A, and B are simultaneously added dropwise to solution C, and the addition rates of solution A and B are controlled to maintain the pH at 9.5, and the pH value is monitored. The obtained mixed solution is aged in a water bath at 60 °C for 12 hours, and then the product is collected by centrifugation, washed 5 times with deionized water, and finally dried overnight in a vacuum drying oven at 60 °C. The obtained composite material is labeled as CuAl / LDH-DE.

[0068] (3) Preparation of CuAl / LDH-DE material:

[0069] Put the CuAl / LDH-DE sample into 100 mL of deionized aqueous solution containing 0.1 M ethylenediaminetetraacetic acid (EDTA) and 0.08 M tea polyphenols. Adjust the pH value of the solution to 9 by adding 0.1 M NaOH. Then put the obtained solution into a hydrothermal reactor and keep it at a temperature of 65 °C for 12 hours. After the reaction, the obtained sample is thoroughly washed with ethanol and dried for use, and the obtained composite material is marked as EDTA / TP-CuAl / LDH-DE.

[0070] (4) Preparation of Ag@EDTA / TP-CuAl / LDH-DE:

[0071] Under light-shielded conditions, impregnate 100 mg of the EDTA / TP-CuAl / LDH-DE composite material in 0.4 M AgNO3 solution (100 mL), and keep stirring gently or standing still for 2 hours in the dark to ensure that Ag+ is fully adsorbed on the surface and between the layers of the material. Subsequently, centrifuge and separate the material, wash it 3 times with deionized water to remove free Ag+, and mark it as Ag@EDTA / TP-CuAl / LDH-DE after drying in vacuum at 60 °C; that is the said composite material.

[0072] (5) Use of preparing the said composite material into composite particles and then into a multi-layer gradient filtration structure for acarid removal material; same as Example 1.

[0073] Figure 1 (d-d2) is the scanning electron micrograph of the Ag@EDTA / TP-CuAl / LDH-DE composite material obtained in this example; it can be seen from the figure that the particle morphology of the material is relatively rough, and it has a higher porosity, and there are a large number of pore structures on the surface, which may provide a larger specific surface area, help adsorb acarids, and improve the release rate of active substances. Figure 2 (d-d1) is the acarid removal effect diagram of the Ag@EDTA / TP-CuAl / LDH-DE composite material obtained in this example, which is the micrograph after 14 days of acaricidal treatment; it can be seen from the figure that the mortality rate of acarids is relatively high, but some individuals are still intact, which may be due to the rapid release of the material and the significant short-term acaricidal effect. Figure 3 (d-d1) is the scanning electron micrograph of the Ag@EDTA / TP-CuAl / LDH-DE composite material after 14 days of acarid removal in this example. It can be seen from the figure that there are fewer remaining acarid individuals, but it can still be observed that the acarids are not completely decomposed. Figure 4Antibacterial rate graph of the composite materials obtained in Examples 1-4; It can be seen from the figure that the antibacterial rate of the Ag@EDTA / TP-CuAl / LDH-DE composite material obtained in this example against Escherichia coli after 40 days is 91.59%, and the antibacterial rate against Staphylococcus aureus after 40 days is 90.59%. Table 1 shows the comparison of the killing rates of the mite removal bags and commercially available mite removal bags against Dermatophagoides farinae. The killing rate of the mite removal bag in this example is 100.0±0 on the first day of action, 13±6.5 on the 7th day, and 0±0 on the 14th day. Table 2 shows the calculation indexes of the mite removal bag. The moisture content of the mite removal bag in this example is 7%, the powder falling rate is 1%, and the compressive strength is 80 N / particle.

[0074] Table 1 Comparison of the killing rates of the mite removal bags in Examples 1-4 and commercially available mite removal bags (control example) against Dermatophagoides farinae

[0075]

[0076] Table 2 Technical indexes of the mite removal bags in Examples 1-4 and commercially available mite removal bags (control example)

[0077]

[0078] In summary, through the diatomite pretreatment and 3D bionic structure design, the present invention realizes the uniform loading of nanoparticles and the densification of the structure (smooth surface, spherical distribution), significantly improving the material performance. As the concentrations of Cu and Ag ions increase, the material changes from loose (Examples 1-2) to a dense and stable structure (Example 3, (0.03 mol of Cu(NO3)2·3H2O, 0.06 M of tea polyphenols, 0.3 M of AgNO3)), and the antibacterial rate of nano-metal ions is significantly improved (98.55% for Escherichia coli and 97.21% for Staphylococcus aureus), far exceeding other examples. Its mite removal effect is outstanding. Through physical adsorption (200-nm pores of diatomite) and chemical synergistic effects (CuAl / LDH slow-release ions damage cell membranes, Ag+ interferes with metabolism, and tea polyphenol-EDTA oxidizes the epidermal lipid layer), it can penetrate the surface layer of mites to cause the outer shell to disintegrate (SEM shows complete destruction), achieving a long-term killing rate of 100% on the first day and 15.75% on the 7th day. The filter element adopts a three-layer gradient structure (intercepting large particles, adsorbing and sterilizing, and nano-film intercepting), combined with the high compressive strength (90 N / particle) and low release rate of Example 3, ensuring mechanical stability and long-term function. Generally speaking, Example 3 is the best in terms of structural uniformity, antibacterial broad-spectrum, mite killing efficiency, and filter element durability, providing an efficient and controllable solution for air purification and mite removal applications.

[0079] The above is only used to introduce the specific implementation manners of the present invention in detail, but the technical solutions proposed by the present invention are not limited to the above methods. Without departing from the basic principles of the present technology, equivalent modifications and changes made by those skilled in the art to the technologies proposed by the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a composite material, characterized in that: The steps include: (1) Pretreatment of diatomite: adding disc-shaped diatomite to a NaOH solution; mixing, separating, washing at a certain temperature, and drying at a certain temperature to obtain pretreated diatomite; (2) Preparation of CuAl / LDH-DE: copper salt and aluminum salt are dissolved in water to form solution A, NaOH is dissolved in water to form solution B, and Na2CO3 is dissolved in water to form solution C; pretreated diatomaceous earth, solutions A and B are simultaneously added dropwise to solution C, and the pH value of the mixed solution is maintained at 9.0-10.0; the obtained mixed solution is aged at a certain temperature for a period of time, separated, washed, and vacuum dried, and the obtained material is recorded as CuAl / LDH-DE; (3) Preparation of EDTA / TP-CuAl / LDH-D: CuAl / LDH-DE was placed in a mixed solution containing ethylenediaminetetraacetic acid and tea polyphenols, and the pH value was adjusted to 8.5-9.5; then it was kept at a certain temperature for a period of time; After separation, washing and drying, the obtained material was recorded as EDTA / TP-CuAl / LDH-DE; (4) Preparation of composite materials: EDTA / TP-CuAl / LDH-DE was immersed in a silver salt solution and kept for a period of time, and then separated, washed, and vacuum dried. The obtained material was recorded as Ag@EDTA / TP-CuAl / LDH-DE; that is, the composite material.

2. The preparation method according to claim 1, characterized in that: Step (1) adding disc-shaped diatomaceous earth with a particle size of 20-25 μm and a pore size of 150-250 nm to a 5-7 wt % NaOH solution so that the mass fraction of the diatomaceous earth is 3-5 wt %; vigorously stirring the mixture at 50-70° C. for more than 1 hour, separating the mixture; then washing with distilled water until the precipitate is neutral; finally, drying the washed precipitate in an oven at 100-120° C. for more than 10 hours.

3. The preparation method according to claim 1, characterized in that: In step (2), the copper salt and the aluminum salt are added in a molar ratio of (1-4):1; the mixed solution is aged at 50-70°C for more than 10 hours; and the copper salt or the aluminum salt is a nitrate.

4. The preparation method according to claim 1, characterized in that: The addition amount of EDTA and tea polyphenols in step (3) is 10:(1-10) in molar ratio; pH value is adjusted with NaOH solution; the temperature is maintained at 60-70° C. for more than 10 hours; and ethanol is used for washing.

5. The preparation method according to claim 1, characterized in that: Step (4) immersing EDTA / TP-CuAl / LDH-DE in a silver salt solution and keeping it for a period of time under light-proof conditions; washing with water, and vacuum drying at 50-70° C. to obtain the composite material.

6. The composite material prepared according to the preparation method according to any one of claims 1 to 5.

7. Use of the composite material according to claim 6 as a mite removal material.

8. The use according to claim 7, characterized in that The composite material is prepared into composite particles and then prepared into a multi-layer gradient filtration structure.

9. The use according to claim 8, characterized in that The preparation steps of the composite particles are as follows: treating the activated carbon particles with nitric acid, washing them with water to neutralize them, and then drying them; then mixing them with the composite material in a certain mass ratio, adding a binder so that the composite material is evenly loaded on the pores and surface of the activated carbon; and then vacuum drying to obtain the composite particles.

10. The use according to claim 8, characterized in that The multi-layer gradient filtration structure consists of three layers, and its preparation steps are as follows: fill the composite particles into the mold, and prepare a porous filter element matrix under a certain temperature and pressure; use the porous filter element matrix as the middle layer, the outer layer is a polypropylene melt-blown non-woven fabric layer of a certain thickness, and the inner layer is an electrospun nanofiber membrane; use epoxy resin glue to bond the three layers of materials and cure them for a period of time to obtain a three-layer gradient filtration structure.

Images