Antibacterial material, formaldehyde-removing and antibacterial air purification composite material and preparation method thereof

Abstract

The present invention discloses an antibacterial material, a formaldehyde-removing and antibacterial air purification composite material, and a preparation method thereof. The preparation method of the antibacterial material comprises calcining diatomaceous earth at 200°C to 600°C for 60 minutes to 180 minutes, then modifying the calcined diatomaceous earth with a Class A silane coupling agent, and loading silver nanoparticles and / or copper nanoparticles on the Class A silane coupling agent-modified diatomaceous earth. The technical solution of the present invention prepares diatomaceous earth with a maximized and intact microporous structure through a calcination method, thereby maximizing its specific surface area and achieving the diatomaceous earth's loading of the above-mentioned antibacterial nanoparticles, avoiding the problem of easy agglomeration of nano-antibacterial particles, improving the dispersion effect, enhancing the antibacterial efficiency, and reducing the cost of the antibacterial material. On the other hand, the Class A silane coupling agent-modified diatomaceous earth purifies indoor air by utilizing the mechanism by which formaldehyde easily reacts with amino groups to form azomethine and Schiff base chemical structures, which can not only specifically adsorb aldehyde pollutants but also ensure the stability of adsorption to a certain extent.

Description

Technical Field

[0001] The present invention relates to the technical field of formaldehyde purification, and in particular to an antibacterial material, a formaldehyde-removing and antibacterial air purification composite material and a preparation method thereof. Background Art

[0002] There are many types of air purifiers on the market. To improve the market competitiveness of air purifiers, the materials used for air filters and filter screens must not only ensure product quality but also reduce costs. Diatomaceous earth resources are abundant and have been developed for use as filter aids, but there are still problems such as lagging research and development and low comprehensive utilization rates. Diatomaceous earth, mainly composed of SiO2, has a unique pore structure, high porosity, good adsorption properties, light weight, and stable chemical properties. It is a natural and environmentally friendly material. Currently, diatomaceous earth has been developed as a functional interior wall finishing material for removing harmful substances from indoor air. However, simple physical adsorption using the voids in diatomaceous earth can release harmful substances such as bacteria or formaldehyde as the indoor environment and temperature change. Summary of the Invention

[0003] One of the main purposes of the present invention is to provide a method for preparing an antibacterial material, aiming to solve the problem that diatomaceous earth cannot effectively fight bacteria under environmental changes.

[0004] To achieve the above objectives, the present invention provides a method for preparing an antibacterial material, comprising calcining diatomaceous earth at 200°C to 600°C for 60 minutes to 180 minutes, then modifying the calcined diatomaceous earth with a Class A silane coupling agent, and loading silver nanoparticles and / or copper nanoparticles on the Class A silane coupling agent-modified diatomaceous earth, wherein the Class A silane coupling agent includes an amino-containing silane coupling agent.

[0005] In some embodiments of the present invention, the specific steps of modifying the calcined diatomite with a silane coupling agent include adding the calcined diatomite to an S1 solvent and ultrasonicating for t1 min to form an S1 solution of calcined diatomite; adding a type A silane coupling agent to the S1 solution of calcined diatomite, refluxing at T1°C and magnetically stirring for t2h, washing the precipitate and drying it at T2°C to obtain the type A silane coupling agent-modified diatomite.

[0006] In some embodiments of the present invention, the washing and precipitation refers to washing and precipitating the product after reflux and stirring with ethanol and deionized water respectively for three times by centrifugation, and drying at T2 to obtain diatomaceous earth modified with a type A silane coupling agent.

[0007] In some embodiments of the present invention, the S1 solvent is toluene or ethanol, t1min is 30min-60min, T1°C is 80°C-85°C, t2h is 10h-20h, and T2°C is 60°C-80°C.

[0008] In some embodiments of the present invention, the ratio of the calcined diatomaceous earth: toluene or ethanol: type A silane coupling agent is 1 g: 100 mL: (1 mL to 3 mL).

[0009] In some embodiments of the present invention, the type A silane coupling agent includes 3-aminopropyltriethoxysilane.

[0010] In some embodiments of the present invention, the step of loading silver nanoparticles and / or copper nanoparticles is as follows: the diatomaceous earth modified by the type A silane coupling agent is dispersed with the S2 solvent and ultrasonicated for t3 min, a silver nitrate solution and / or a copper nitrate solution is added, the reaction is carried out under light-shielding and stirring for t4 min at T3°C, the S3 solution is added dropwise, stirred and mixed for t5 min, and then a sodium borohydride solution is added dropwise, the reaction is carried out at T4°C for t6 min, centrifuged and washed, and freeze-dried to obtain the type A silane coupling agent-modified diatomaceous earth loaded with nano-silver and / or nano-copper.

[0011] In some embodiments of the present invention, the S2 solvent is ethanol, the S3 solution is a polyvinylpyrrolidone aqueous solution, t3min is 60min~120min, T3℃ is 20℃~25℃, t4min is 80min~150min, t5min is 20min~60min, T4℃ is 20℃~25℃, and t6min is 10min~20min.

[0012] In some embodiments of the present invention, the ratio of the mass of the Class A silane coupling agent modified diatomaceous earth: S2 solvent: S3 solution solute is 40 mg: 20 mL: 4 mg, the ratio of the concentration of silver nitrate solution: the concentration of copper nitrate solution: the concentration of sodium borohydride solution is 0.002 mol / L: 0.002 mol / L: 0.005 mol / L, the ratio of the volume of silver nitrate solution: the volume of copper nitrate solution: the volume of sodium borohydride solution: the volume of S3 solution is 5-20 mL: 5-20 mL: 10 mL: 10-50 mL, and the ratio of the volume of S2 solvent: the volume of S3 solution is 20-100 mL: 10-50 mL.

[0013] In some embodiments of the present invention, the ratio of the solute mass of the type A silane coupling agent modified diatomaceous earth: S2 solvent: S3 solution is 40 mg: 20 mL: 4 mg, the ratio of the concentration of silver nitrate solution: the concentration of sodium borohydride solution is 0.002 mol / L: 0.005 mol / L, the ratio of the volume of silver nitrate solution: the volume of sodium borohydride solution: the volume of S3 solution is 5-20 mL: 10 mL: 10-50 mL, and the ratio of the volume of S2 solvent: the volume of S3 solution is 20-100 mL: 10-50 mL.

[0014] In some embodiments of the present invention, the ratio of the solute mass of the type A silane coupling agent modified diatomaceous earth: S2 solvent: S3 solution is 40 mg: 20 mL: 4 mg, the ratio of the concentration of copper nitrate solution: the concentration of sodium borohydride solution is 0.002 mol / L: 0.005 mol / L, the volume of copper nitrate solution: the volume of sodium borohydride solution: the volume of S3 solution is 5-20 mL: 10 mL: 10-50 mL, and the ratio of the volume of S2 solvent: the volume of S3 solution is 20-100 mL: 10-50 mL.

[0015] It should be noted that the solute of the S3 solution is S3. For example, if the S3 solution is a polyvinyl pyrrolidone solution, the solute of the S3 solution is polyvinyl pyrrolidone.

[0016] The present invention also provides an antibacterial material prepared by the above preparation method.

[0017] The present invention also provides an application of the antibacterial material prepared by the above preparation method in antibacterial products.

[0018] A second main purpose of the present invention is to provide a method for preparing a formaldehyde-removing and antibacterial air purification composite material, aiming to solve the problem of poor formaldehyde adsorption capacity of existing antibacterial materials. The method comprises the following steps: calcining diatomaceous earth at 200°C to 600°C for 60 minutes to 180 minutes, placing it in deionized water and stirring it to form a suspension, then adding a type B silane coupling agent, stirring it at a constant temperature of T5°C for t7 hours, then washing, filtering, and drying it at a constant temperature of T6°C. The type B silane coupling agent includes an amino-containing silane coupling agent;

[0019] The type B silane coupling agent modified diatomaceous earth prepared by the above preparation method is mixed with the antibacterial material described in the above technical solution in a mixing ratio of 2:7 to 7:2.

[0020] In some embodiments of the present invention, T5°C is 50°C to 70°C, t7h is 1 to 3h, and T6°C is 50°C to 70°C.

[0021] In some embodiments of the present invention, the ratio of diatomaceous earth: deionized water: type B silane coupling agent is 1 g: 10 mL: 2.4 mmol.

[0022] In some embodiments of the present invention, the type B silane coupling agent includes 3-aminopropylmethyldimethoxysilane and / or γ-aminopropyltriethoxysilane.

[0023] In some embodiments of the present invention, the diatomaceous earth modified with the type B silane coupling agent and the antibacterial material prepared by the above preparation method are mixed in a ratio of 1:1.

[0024] The present invention also provides a formaldehyde-removing and antibacterial air purification composite material prepared by the above preparation method.

[0025] The present invention also provides an application of the formaldehyde-removing and antibacterial air purification composite material prepared by the above preparation method in products requiring formaldehyde purification function and / or products requiring antibacterial performance and / or in products requiring both formaldehyde purification and antibacterial functions.

[0026] The present invention also provides an application of the formaldehyde-removing and antibacterial air-purifying composite material prepared by the above preparation method in an air purifier.

[0027] It should be noted that the type A silane coupling agent and the type B silane coupling agent may be of the same kind or the same type, or may be of different kinds or different types.

[0028] The antibacterial material preparation method of the present invention prepares diatomaceous earth with a maximized and intact microporous structure by a roasting method to maximize its specific surface area, and then supports nanosilver and / or nanocopper on the diatomaceous earth to achieve high adsorption of the nanosilver and / or nanocopper on the diatomaceous earth. The nanosilver and nanocopper are sterilized by their individual action or synergistic action, and the sterilization effect is good. In addition, the diatomaceous earth modified with a type A silane coupling agent (containing amino groups) can achieve good adsorption of formaldehyde. This is because formaldehyde easily forms azomethine and Schiff base chemical structures with amino groups. Therefore, when applied to indoor air purification, it can not only specifically adsorb aldehyde pollutants, but also ensure the stability of adsorption to a certain extent.

[0029] Since bacteria double in number every 20 to 30 minutes, killing a single species with a single method leaves room for other bacteria to grow, resulting in an ineffective reduction in the total bacterial population and failure to achieve the desired sterilization effect. Therefore, silver nanoparticles and copper nanoparticles are used in appropriate ratios for sterilization. Although the difference in effectiveness may appear to be only a few percentage points or even a fraction of a percentage point, this difference is not a simple one-plus-one addition. Rather, it is achieved through the synergistic killing of different types of bacteria by the different sterilization mechanisms of nanosilver and nanocopper. Therefore, this is a combined invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0031] Figure 1 SEM images of diatomaceous earth-loaded copper / silver nanoparticles;

[0032] Figure 2This is the infrared characterization of diatomaceous earth modified with type I silane coupling agent in antibacterial materials. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0035] In addition, the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0036] The present invention provides a method for preparing an antibacterial material, aiming to solve the problem that diatomaceous earth cannot effectively resist bacteria under environmental changes. The method comprises the following steps: calcining diatomaceous earth at 200°C to 600°C for 60 minutes to 180 minutes, then modifying the calcined diatomaceous earth with a Class A silane coupling agent, and loading silver nanoparticles and / or copper nanoparticles on the diatomaceous earth modified with the Class A silane coupling agent, wherein the Class A silane coupling agent includes an amino-containing silane coupling agent.

[0037] When the calcination temperature of the diatomaceous earth is below 200°C, or the calcination time is less than 60 minutes, the organic matter and sticky substances in the diatomaceous earth are not effectively removed, the microporous structure is blocked, and the silane coupling agent cannot be effectively adsorbed, and the loading amount of nanosilver and / or nanocopper is too small, resulting in ineffective sterilization due to too little effective bactericidal components. When the calcination temperature of the diatomaceous earth is above 600°C, or the calcination time is more than 180 minutes, the microporous structure of the diatomaceous earth is destroyed, and the silane coupling agent cannot be effectively adsorbed, and the loading amount of nanosilver and / or nanocopper is too small, resulting in ineffective sterilization due to too little effective bactericidal components. Diatomaceous earth modified with a Class A silane coupling agent can achieve better adsorption of formaldehyde, because formaldehyde easily forms azomethine and Schiff base chemical structures with amino groups. Therefore, when applied to indoor air purification, it can not only specifically adsorb aldehyde pollutants, but also ensure the stability of adsorption to a certain extent.

[0038] The above-mentioned antibacterial material preparation method uses a roasting method to prepare diatomaceous earth with a maximized and intact microporous structure to maximize its specific surface area, and then supports nanosilver and / or nanocopper on the diatomaceous earth to achieve high adsorption of nanosilver and / or nanocopper on the diatomaceous earth. The sterilization effect is good through the individual action of nanosilver and nanocopper or their synergistic action. The diatomaceous earth modified with a type A silane coupling agent can achieve good adsorption of formaldehyde. This is because formaldehyde easily forms azomethine and Schiff base chemical structures with amino groups. Therefore, when applied to indoor air purification, it can not only specifically adsorb aldehyde pollutants, but also ensure the stability of adsorption to a certain extent.

[0039] Since bacteria double in number every 20 to 30 minutes, killing a single species with a single method leaves room for other bacteria to grow, resulting in an ineffective reduction in the total bacterial population and failure to achieve the desired sterilization effect. Therefore, silver nanoparticles and copper nanoparticles are used in appropriate ratios for sterilization. Although the difference in effectiveness may appear to be only a few percentage points or even a fraction of a percentage point, this difference is not a simple one-plus-one addition. Rather, it is achieved through the synergistic killing of different types of bacteria by the different sterilization mechanisms of nanosilver and nanocopper. Therefore, this is a combined invention.

[0040] In some embodiments of the present invention, the calcination temperature of diatomaceous earth is 400°C.

[0041] When the diatomite is calcined at 400°C, the removal of sticky and organic matter from the microporous structure is optimal. Above this temperature, while the microporous structure does not deform, the specific surface area of ​​the diatomite decreases slightly after heating. Below this temperature, the removal of sticky and organic matter from the microporous structure is incomplete.

[0042] In some embodiments of the present invention, the specific steps of modifying the calcined diatomite with a silane coupling agent include adding the calcined diatomite to an S1 solvent and ultrasonicating for t1 min to form an S1 solution of calcined diatomite; adding a type A silane coupling agent to the S1 solution of calcined diatomite, refluxing at T1°C and magnetically stirring for t2h, washing the precipitate and drying it at T2°C to obtain the type A silane coupling agent-modified diatomite.

[0043] S1 solvent is a good solvent for diatomaceous earth. Ultrasonication of diatomaceous earth in S1 can maximize the dispersion of diatomaceous earth. When adding type A silane coupling agent, the dispersed silane coupling agent can be attached to the surface of diatomaceous earth with a large active surface area due to full dispersion and react with the diatomaceous earth by reflux magnetic stirring. Diatomaceous earth modified with type A silane coupling agent can achieve better adsorption of formaldehyde. This is because formaldehyde easily forms azomethine and Schiff base chemical structures with amino groups. Therefore, its application in indoor air purification can not only specifically adsorb aldehyde pollutants, but also ensure the stability of adsorption to a certain extent.

[0044] In some embodiments of the present invention, the S1 solvent is toluene or ethanol, t1min is 30min-60min, T1°C is 80°C-85°C, t2h is 10h-20h, and T2°C is 60°C-80°C.

[0045] Toluene or ethanol are good solvents for diatomaceous earth. Ultrasonication of diatomaceous earth in toluene or ethanol maximizes its dispersion. When a Type A silane coupling agent is added, the dispersed silane coupling agent can be maximized through reflux magnetic stirring to adhere to and react with the diatomaceous earth, which has a large active surface area due to its thorough dispersion. If t1 is less than 30 minutes, the diatomaceous earth is not fully dispersed, resulting in insufficient silane coupling agent adhesion and insufficient formaldehyde removal. If t1 is greater than 60 minutes, the diatomaceous earth may be overactivated and shrink, destroying its micropore structure and surface structure, resulting in insufficient silane coupling agent adhesion and formaldehyde removal. If t2 is less than 10 hours or T1 is less than 80°C, the silane coupling agent has insufficient time to react with the diatomaceous earth, resulting in insufficient adhesion and formaldehyde removal. If t2 is greater than 20 hours or T1 is greater than 85°C, the diatomaceous earth may shrink upon activation, destroying its micropore structure and surface structure, and thus insufficient formaldehyde removal. When T2 is less than 60°C, it is impossible to effectively dry liquid substances such as toluene or ethanol and obtain diatomaceous earth modified with a type A silane coupling agent. When T2 is greater than 80°C, the diatomaceous earth will be activated and agglomerated, thereby reducing the specific surface area of ​​the diatomaceous earth modified with a type A silane coupling agent and making the formaldehyde removal function insufficient.

[0046] In some embodiments of the present invention, the washing precipitation refers to washing the product after reflux stirring with ethanol and deionized water respectively for three times by centrifugation, and drying at T2°C to obtain diatomaceous earth modified with a type A silane coupling agent.

[0047] Centrifugal washing with ethanol and deionized water can remove organic and inorganic impurities in the product, respectively. After three centrifugal washings with ethanol and deionized water, the impurities are essentially removed. If T2 is less than 60°C, the diatomaceous earth modified with the type A silane coupling agent is difficult to dry, and if T2 is greater than 80°C, the diatomaceous earth modified with the type A silane coupling agent tends to agglomerate.

[0048] In some embodiments of the present invention, the ratio of the calcined diatomaceous earth: toluene or ethanol: type A silane coupling agent is 1 g: 100 mL: (1 mL to 3 mL).

[0049] The aforementioned ratios of calcined diatomaceous earth, toluene or ethanol, and a Type A silane coupling agent allow the calcined diatomaceous earth to be fully dispersed in the toluene or ethanol. When the amount of the Type A silane coupling agent is less than 1 mL, the formaldehyde removal effect is insufficient due to the low content. When the amount of the Type A silane coupling agent is greater than 3 mL, further addition of the Type A silane coupling agent will not improve the formaldehyde removal effect.

[0050] In some embodiments of the present invention, the type A silane coupling agent includes 3-aminopropyltriethoxysilane.

[0051] Diatomaceous earth modified with 3-aminopropyltriethoxysilane can achieve high adsorption of formaldehyde. This is because formaldehyde easily forms azomethine and Schiff base chemical structures with amino groups. Therefore, its application in indoor air purification can not only specifically adsorb aldehyde pollutants, but also ensure the stability of adsorption to a certain extent.

[0052] In some embodiments of the present invention, the step of loading silver nanoparticles and / or copper nanoparticles is as follows: the diatomaceous earth modified by the type A silane coupling agent is dispersed with the S2 solvent and ultrasonicated for t3 min, a silver nitrate solution and / or a copper nitrate solution is added, the reaction is carried out under light-shielding and stirring for t4 min at T3°C, the S3 solution is added dropwise, stirred and mixed for t5 min, and then a sodium borohydride solution is added dropwise, the reaction is carried out at T4°C for t6 min, centrifuged and washed, and freeze-dried to obtain the type A silane coupling agent-modified diatomaceous earth loaded with nano-silver and / or nano-copper.

[0053] The amino group does not react with the S2 solvent, and the S2 solvent is a good solvent for diatomaceous earth, so the diatomaceous earth modified with the type A silane coupling agent is dispersed in the S2 solvent. The S3 solution is used to control the particle size of nanosilver and / or nanocopper within a certain range.

[0054] In some embodiments of the present invention, the S2 solvent is ethanol, the S3 solution is a polyvinylpyrrolidone aqueous solution, t3min is 60min~120min, T3℃ is 20℃~25℃, t4min is 80min~150min, t5min is 20min~60min, T4℃ is 20℃~25℃, and t6min is 10min~20min.

[0055] Because amino groups do not react with ethanol, and ethanol is a good solvent for diatomaceous earth, diatomaceous earth modified with a type A silane coupling agent is dispersed in ethanol. When t3 is less than 60 minutes, the diatomaceous earth is not fully dispersed. When t3 is greater than 120 minutes, the diatomaceous earth may be overactivated and shrink, resulting in a decrease in active surface area. Since silver nitrate solutions and / or copper nitrate solutions decompose in the presence of light, subsequent light-shielding reactions are required. When T3 is less than 20°C or t4 is shorter than 80 minutes, the reaction is incomplete and the loading capacity is low. When T3 is greater than 25°C or t4 is longer than 150 minutes, the reaction is too complete, resulting in large nanosilver and / or nanocopper particle sizes, which affects the bactericidal effect. Polyvinyl pyrrolidone aqueous solution is used to control the particle size of nanosilver and / or nanocopper within a certain range. When t5 is less than 20 minutes, the resulting nanosilver and / or nanocopper particles are too small and the loading capacity is low. When t5 is greater than 60 minutes, the resulting nanosilver and / or nanocopper particles are too large, affecting the bactericidal effect. Sodium borohydride solution is used to prepare nanosilver and / or nanocopper via a reduction method. When T4 is less than 20°C or t6 is shorter than 10 minutes, the reaction is incomplete and the loading capacity is low. When T4 is greater than 25°C or t6 is longer than 20 minutes, the reaction is too complete, resulting in large nanosilver and / or nanocopper particles, affecting the bactericidal effect. Furthermore, dropwise addition is used to ensure a more complete and controllable reaction, avoiding overly rapid reactions or runaway reactions.

[0056] In some embodiments of the present invention, the ratio of the mass of the Class A silane coupling agent modified diatomaceous earth: S2 solvent: S3 solution solute is 40 mg: 20 mL: 4 mg, the ratio of the concentration of silver nitrate solution: the concentration of copper nitrate solution: the concentration of sodium borohydride solution is 0.002 mol / L: 0.002 mol / L: 0.005 mol / L, the ratio of the volume of silver nitrate solution: the volume of copper nitrate solution: the volume of sodium borohydride solution: the volume of S3 solution is 5-20 mL: 5-20 mL: 10 mL: 10-50 mL, and the ratio of the volume of S2 solvent: the volume of S3 solution is 20-100 mL: 10-50 mL.

[0057] In some embodiments of the present invention, the ratio of the solute mass of the type A silane coupling agent modified diatomaceous earth: S2 solvent: S3 solution is 40 mg: 20 mL: 4 mg, the ratio of the concentration of silver nitrate solution: the concentration of sodium borohydride solution is 0.002 mol / L: 0.005 mol / L, the ratio of the volume of silver nitrate solution: the volume of sodium borohydride solution: the volume of S3 solution is 5-20 mL: 10 mL: 10-50 mL, and the ratio of the volume of S2 solvent: the volume of S3 solution is 20-100 mL: 10-50 mL.

[0058] In some embodiments of the present invention, the ratio of the solute mass of the type A silane coupling agent modified diatomaceous earth: S2 solvent: S3 solution is 40 mg: 20 mL: 4 mg, the ratio of the concentration of copper nitrate solution: the concentration of sodium borohydride solution is 0.002 mol / L: 0.005 mol / L, the volume of copper nitrate solution: the volume of sodium borohydride solution: the volume of S3 solution is 5-20 mL: 10 mL: 10-50 mL, and the ratio of the volume of S2 solvent: the volume of S3 solution is 20-100 mL: 10-50 mL.

[0059] Using this ratio, the diatomaceous earth modified with the type A silane coupling agent can be dispersed to the greatest extent possible in the S2 solvent, such as ethanol, without destroying its structure. Using the above volume ratios and concentrations of the S3 solution, such as a polyvinyl pyrrolidone aqueous solution and a sodium borohydride solution, the particle size of the silver or copper nanoparticles can be effectively controlled in combination with the volume and concentration of the silver nitrate or copper nitrate solution, thereby preventing poor particle uniformity or excessively large or small particle sizes.

[0060] In some embodiments of the present invention, the sodium borohydride solution is added dropwise at a constant pressure.

[0061] The purpose of dropwise addition is to make the reaction more complete and controllable, and to avoid excessive reaction or loss of control. The purpose of constant pressure addition is to make the droplet volume basically consistent, and to avoid uneven reaction.

[0062] The present invention also provides an antibacterial material prepared by the above preparation method.

[0063] The antibacterial material prepared by the above preparation method has an antibacterial effect of more than 90%, and can be as high as close to 100%.

[0064] Figure 1 This is an SEM image of the antibacterial material loaded with silver nanoparticles and copper nanoparticles. It can be seen from the figure that the silver nanoparticles and copper nanoparticles have been loaded on the diatomaceous earth modified with a type 1 silane coupling agent.

[0065] The present invention also provides an application of the antibacterial material prepared by the above preparation method in antibacterial products.

[0066] Figure 2 This is the infrared characterization of diatomaceous earth modified by type A silane coupling agent in antibacterial materials, at 1102 cm -1 、793cm -1 and 483cm -1 The absorption peaks at 1301cm correspond to the characteristic peaks of Si-O antisymmetric stretching vibration, Si-O symmetric stretching vibration, and O-Si-O antisymmetric bending vibration, reflecting the basic vibration characteristics of SiO2 tetrahedron in diatomite. -1 It is the deformation vibration absorption peak of OH.

[0067] 2974cm -1 The absorption peaks of CH3 are on the left and right, which are characteristic absorption peaks caused by the asymmetric stretching vibration of CH; 1486 and 1574 cm -1 The characteristic peak at 963cm represents the presence of -NH2; -1 The corresponding absorption peak is Si-O-CH2-. In the infrared spectrum, in addition to the characteristic peaks of common groups of diatomite, there are also absorption peaks of new groups -NH2 and -CH2, which indicates that the aminosilane coupling agent forms chemical adsorption with the surface of diatomite.

[0068] 3300-3500cm -1 The peak at (1) is the stretching vibration peak of OH bond or NH, which may be the NH stretching vibration peak after modification of bound water, hydroxyl group on diatomaceous earth and aminosilane coupling agent. As shown in the figure, the peak gradually weakens after modification, which may be due to the reduction of silicon hydroxyl group after modification, resulting in the weakening of the absorption peak.

[0069] Since the antibacterial material containing diatomaceous earth modified with a type A silane coupling agent has a certain formaldehyde removal effect (see Examples 7 to 9), it can be proved by referring to the above infrared spectra that the type A silane coupling agent has been chemically adsorbed onto the modified diatomaceous earth and removes formaldehyde by easily forming azomethine and Schiff base chemical structures with amino groups.

[0070] Since the antibacterial material prepared by the present invention is in powder form, it is generally used as a filler in antibacterial products to achieve antibacterial function by filtering bacteria in the air and / or liquid. The antibacterial effect of the antibacterial product of the present invention is as high as over 90%, and the highest is close to 100%. See the examples for details, so it has a wide range of applications. The antibacterial material also has the effect of removing formaldehyde, but the formaldehyde removal effect is limited when used alone.

[0071] A second main purpose of the present invention is to provide a method for preparing a formaldehyde-removing and antibacterial air purification composite material, which aims to solve the problem of poor formaldehyde adsorption capacity of existing antibacterial materials. The method comprises the following steps: calcining diatomaceous earth at 200°C to 600°C for 60 minutes to 180 minutes, placing it in deionized water and stirring it to form a suspension, then adding a Class B silane coupling agent, stirring it at a constant temperature of T5°C for t7 hours, then washing, filtering, and drying it at a constant temperature of T6°C; mixing the Class B silane coupling agent-modified diatomaceous earth prepared by the above preparation method with the antibacterial material prepared by the above preparation method, with a mixing ratio of 2:7 to 7:2, wherein the Class B silane coupling agent includes an amino-containing silane coupling agent.

[0072] When the diatomite is calcined at a temperature below 200°C or for a time of less than 60 minutes, organic matter and sticky substances in the diatomite are not effectively removed, and the microporous structure is blocked, making it unable to effectively adsorb silane coupling agents. When the diatomite is calcined at a temperature above 600°C or for a time of more than 180 minutes, the microporous structure of the diatomite is destroyed, making it unable to effectively adsorb silane coupling agents.

[0073] The calcined diatomaceous earth only needs to be loaded with a Class B silane coupling agent to enable it to have the function of formaldehyde adsorption. Deionized water is used to prepare a suspension containing the calcined diatomaceous earth, and then the Class B silane coupling agent is added. After a period of constant temperature reaction, the Class B silane coupling agent is washed and dried to achieve the loading of the Class B silane coupling agent. The antibacterial material is mixed with the diatomaceous earth modified with the Class B silane coupling agent to achieve the two functions of formaldehyde adsorption and long-term antibacterial.

[0074] In some embodiments of the present invention, the calcination temperature of diatomaceous earth is 400°C.

[0075] When the diatomite is calcined at 400°C, the removal of sticky and organic matter from the microporous structure is optimal. Above this temperature, while the microporous structure does not deform, the specific surface area of ​​the diatomite decreases slightly after heating. Below this temperature, the removal of sticky and organic matter from the microporous structure is incomplete.

[0076] In some embodiments of the present invention, T5°C is 50°C to 70°C, t7h is 1 to 3h, and T6°C is 50°C to 70°C.

[0077] When T5 is less than 50°C or t7 is less than 1h, the loading of the Type B silane coupling agent is insufficient. When T5 is greater than 70°C or t7 is greater than 180min, the diatomaceous earth is overactivated, resulting in a shrinkage reaction. The product is then washed to remove inorganic impurities, generally with water. The solid is then filtered and dried. When T6 is less than 50°C, it is difficult to obtain a dry product. When T6 is greater than 70°C, the product may agglomerate and fail to effectively perform its formaldehyde adsorption function. The diatomaceous earth with formaldehyde adsorption function is then mixed with the antibacterial material. If the mixing ratio is too low, the formaldehyde adsorption function is poor, while if the mixing ratio is too high, the antibacterial performance is poor.

[0078] In some embodiments of the present invention, the ratio of diatomaceous earth: deionized water: type B silane coupling agent is 1 g: 10 mL: 2.4 mmol.

[0079] By adopting the above ratio, the diatomaceous earth can be fully mixed with the type B silane coupling agent in deionized water, so as to fully support the type B silane coupling agent.

[0080] In some embodiments of the present invention, the type B silane coupling agent includes 3-aminopropylmethyldimethoxysilane and / or γ-aminopropyltriethoxysilane.

[0081] The above two types of diatomaceous earth modified with Class B silane coupling agents can achieve high adsorption of formaldehyde. This is because formaldehyde easily forms azomethine and Schiff base chemical structures with amino groups. Therefore, when applied to indoor air purification, it can not only specifically adsorb aldehyde pollutants, but also ensure the stability of adsorption to a certain extent. Compared with Example 9, Example 10 adds Class B silane coupling agent to modify the diatomaceous earth, and the adsorption amount of formaldehyde is nearly doubled compared with Example 9. Therefore, this increase must be caused by the adsorbed Class B silane coupling agent. Example 10 can prove that the Class B silane coupling agent must be chemically adsorbed on the modified diatomaceous earth.

[0082] In some embodiments of the present invention, the diatomaceous earth modified with the type B silane coupling agent and the antibacterial material prepared by the above preparation method are mixed in a ratio of 1:1.

[0083] When the mixing ratio is 1:1, the antibacterial and formaldehyde purification effects of the formaldehyde-removing and antibacterial air purification composite material prepared by the above preparation method reach a balance value and a peak value, which meets the actual application requirements and is suitable for practical applications.

[0084] The present invention also provides a formaldehyde-removing and antibacterial air purification composite material prepared by the above preparation method.

[0085] The formaldehyde-removing and antibacterial air purification composite material prepared by the above preparation method has formaldehyde adsorption function and antibacterial performance of more than 90%, and the highest is close to 100%, which meets the actual application requirements.

[0086] The present invention also provides an application of the formaldehyde-removing and antibacterial air purification composite material prepared by the above preparation method in products requiring formaldehyde purification function and / or products requiring antibacterial performance and / or in products requiring both formaldehyde purification and antibacterial functions.

[0087] Since the formaldehyde-removing and antibacterial air purification composite material prepared by the present invention is in powder form, it is generally used as a filler in antibacterial products, and realizes antibacterial and formaldehyde purification functions by filtering bacteria and formaldehyde in the air and / or liquid. The formaldehyde adsorption function and antibacterial performance of the formaldehyde-removing and antibacterial air purification composite material are both as high as more than 90%, and the highest is close to 100%. See the embodiments for details, so it has a wide range of applications.

[0088] The present invention also provides an application of the formaldehyde-removing and antibacterial air-purifying composite material prepared by the above preparation method in an air purifier.

[0089] Since air purifiers require formaldehyde-removing and antibacterial air-purifying composite materials, the formaldehyde-removing and antibacterial air-purifying composite materials provided by the present invention are in powder form, and are therefore generally used as fillers in antibacterial products to achieve antibacterial and formaldehyde-purifying functions by filtering bacteria and formaldehyde in air and / or liquids. The formaldehyde-removing and antibacterial air-purifying composite materials of the present invention have formaldehyde adsorption functions and antibacterial properties of more than 90%, and are as high as close to 100%, making them suitable for use in air purifiers.

[0090] It should be noted that the type A silane coupling agent and the type B silane coupling agent may be of the same kind or the same type, or may be of different kinds or different types.

[0091] The following are examples of the present invention and comparative examples

[0092] The purity and manufacturers of the materials used in the embodiments and comparative examples are as follows:

[0093] Diatomaceous earth, purity level one, purchased from Linjiang Guoxing Diatomaceous Earth Co., Ltd.

[0094] 3-Aminopropyltriethoxysilane, analytical grade, purchased from Cool Chemical Technology (Beijing) Co., Ltd. Silver nitrate, 99.8% pure, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0095] Copper nitrate (Cu(NO3)2·3H2O) with a purity of 99.99% was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0096] Sodium borohydride, analytical grade, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0097] Ethanol, analytical grade, purchased from Beijing Bailingwei Technology Co., Ltd.

[0098] PVP-K30 (polyvinyl pyrrolidone), chromatographically pure, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0099] 3-Aminopropylmethyldimethoxysilane, purity 97%, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0100] γ-Aminopropyltriethoxysilane, purity 99%, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0101] Examples 1 to 4 show the changes in specific surface area of ​​diatomaceous earth after calcination and the formaldehyde adsorption effect.

[0102] Comparative Example 1

[0103] Uncalcined diatomaceous earth has a specific surface area of ​​17.17m 2 / g, the formaldehyde adsorption effect is 18%.

[0104] Example 1

[0105] Weigh a certain amount of diatomaceous earth, calcine it in a muffle furnace at 200°C for 2 h, and then cool it to room temperature in a desiccator for later use.

[0106] Example 2

[0107] A certain amount of diatomaceous earth was weighed and calcined in a muffle furnace at different temperatures of 400°C for 2 h, and then cooled to room temperature in a desiccator for later use.

[0108] Example 3

[0109] A certain amount of diatomaceous earth was weighed and calcined in a muffle furnace at different temperatures of 600°C for 2 h, and then cooled to room temperature in a desiccator for later use.

[0110] Example 4

[0111] A certain amount of diatomaceous earth was weighed and calcined in a muffle furnace at different temperatures of 800°C for 2 h, and then cooled to room temperature in a desiccator for later use.

[0112] The specific surface area of ​​diatomaceous earth was tested using the BET specific surface area test method.

[0113] Table 1 Effect of calcination temperature on the specific surface area of ​​diatom frustules

[0114]

[0115] The diatomaceous earth content used to test the formaldehyde adsorption effect in the examples and comparative examples is consistent.

[0116] When calcined at 200-600°C, the specific surface area of ​​treated diatomite is significantly greater than that of untreated diatomite. However, when calcined at 800°C, the structure of the diatomite is destroyed, and the specific surface area is significantly reduced. Therefore, the temperature of diatomite treatment should be appropriate during the initial treatment. For the diatomite used in this study, a temperature between 200-600°C is beneficial for removing impurities and increasing the specific surface area.

[0117] Diatomaceous earth loaded nano antibacterial particles performance:

[0118] Example 5

[0119] S1. Method of loading copper nanoparticles on diatomaceous earth:

[0120] (1) Pretreatment of diatomaceous earth

[0121] Weigh a certain amount of diatomaceous earth, calcine it in a muffle furnace at 400°C for 2 h, and then cool it to room temperature in a desiccator for later use.

[0122] (2) Modification of diatomite

[0123] Take 1 g of the treated diatomaceous earth and disperse it in 100 mL of toluene or ethanol and ultrasonicate for 30 min;

[0124] Take a round-bottom flask, add the above diatomaceous earth dispersion into the flask, then add 3 mL of 3-aminopropyltriethoxysilane dropwise, reflux at 80 ° C and magnetically stir for 15 h;

[0125] The diatomaceous earth dispersion after the above reaction was centrifuged and washed with ethanol and deionized water for three times, respectively, dried at 65° C., and properly stored.

[0126] (3) Nano-copper ion loaded diatomite

[0127] Prepare 0.01 mol / L copper nitrate solution and 0.025 mol / L sodium borohydride solution for later use;

[0128] Take 0.2 g of modified diatomaceous earth and disperse it in 100 mL of ethanol, and ultrasonicate for 100 min;

[0129] Add 20 mL of copper nitrate to the above ethanol solution, shield from light, and stir to react for 120 minutes at room temperature.

[0130] After 2 h, 0.02 g of PVP-K30 was dispersed in 50 mL of deionized water and then added dropwise to the reaction solution and stirred for 40 min;

[0131] Then, 10 mL of freshly prepared sodium borohydride solution was added dropwise to the reaction solution using a constant pressure funnel and reacted at room temperature for 15 min.

[0132] After the reaction is completed, the mixture is immediately centrifuged, and the precipitate obtained by centrifugation is washed three times with ethanol and deionized water respectively to remove excess reducing agent and PVP; finally, the mixture is freeze-dried for 15 hours to obtain nano-copper-loaded diatomaceous earth (Cu@DME).

[0133] Example 6

[0134] S1. Method of loading silver nanoparticles on diatomaceous earth:

[0135] (1) Pretreatment of diatomaceous earth

[0136] Weigh a certain amount of diatomaceous earth, calcine it in a muffle furnace at 400°C for 2 h, and then cool it to room temperature in a desiccator for later use.

[0137] (2) Modification of diatomite

[0138] Take 1 g of the treated diatomaceous earth and disperse it in 100 mL of toluene or ethanol and ultrasonicate for 30 min;

[0139] Take a round-bottom flask, add the above diatomaceous earth dispersion into the flask, then add 3 mL of 3-aminopropyltriethoxysilane dropwise, reflux at 80 ° C and magnetically stir for 15 h;

[0140] The diatomaceous earth dispersion after the above reaction was centrifuged and washed with ethanol and deionized water for three times, respectively, dried at 65° C., and properly stored.

[0141] (3) Nanosilver ion loaded diatomaceous earth

[0142] Prepare 0.01 mol / L silver nitrate solution and 0.025 mol / L sodium borohydride solution for later use;

[0143] Take 0.2 g of modified diatomaceous earth and disperse it in 100 mL of ethanol, and ultrasonicate for 100 min;

[0144] Take 20 mL of freshly prepared silver nitrate solution and add it to the above ethanol solution. Shield from light and stir at room temperature to react for 120 minutes.

[0145] After 2 h, 0.02 g of PVP-K30 was dispersed in 50 mL of deionized water and then added dropwise to the reaction solution and stirred for 40 min;

[0146] Then, 10 mL of freshly prepared sodium borohydride solution was added dropwise to the reaction solution using a constant pressure funnel and reacted at room temperature for 15 min.

[0147] After the reaction is completed, the mixture is immediately centrifuged and the precipitate obtained by centrifugation is washed three times with ethanol and three times with deionized water to remove excess reducing agent and PVP; finally, the mixture is freeze-dried for 15 hours to obtain diatomaceous earth loaded with nanosilver (Ag@DME).

[0148] Example 7

[0149] S1. Method for loading silver (copper) nanoparticles on diatomaceous earth:

[0150] (1) Pretreatment of diatomaceous earth

[0151] Weigh a certain amount of diatomaceous earth, calcine it in a muffle furnace at 400°C for 2 h, and then cool it to room temperature in a desiccator for later use.

[0152] (2) Modification of diatomite

[0153] Take 1 g of the treated diatomaceous earth and disperse it in 100 mL of toluene or ethanol and ultrasonicate for 30 min;

[0154] Take a round-bottom flask, add the above diatomaceous earth dispersion into the flask, then add 3 mL of 3-aminopropyltriethoxysilane dropwise, reflux at 80 ° C and magnetically stir for 15 h;

[0155] The diatomaceous earth dispersion after the above reaction was centrifuged and washed with ethanol and deionized water for three times, respectively, dried at 65° C., and properly stored.

[0156] (3) Nanosilver / copper ion loaded diatomaceous earth

[0157] Prepare 0.01 mol / L copper nitrate solution, 0.01 mol / L silver nitrate solution, and 0.025 mol / L sodium borohydride solution for later use;

[0158] Take 0.2 g of modified diatomaceous earth and disperse it in 100 mL of ethanol, and ultrasonicate for 100 min;

[0159] Take 10 mL of freshly prepared silver nitrate solution and 10 mL of copper nitrate and add them to the above ethanol solution. Shield from light and stir at room temperature to react for 120 minutes.

[0160] After 2 h, 0.02 g of PVP-K30 was dispersed in 50 mL of deionized water and then added dropwise to the reaction solution and stirred for 40 min;

[0161] Then, 10 mL of freshly prepared sodium borohydride solution was added dropwise to the reaction solution using a constant pressure funnel and reacted at room temperature for 15 min.

[0162] After the reaction is completed, the mixture is immediately centrifuged and the precipitate obtained by centrifugation is washed three times with ethanol and three times with deionized water to remove excess reducing agent and PVP; finally, the mixture is freeze-dried for 15 hours to obtain nanosilver / nanocopper-loaded diatomaceous earth (Ag / Cu@DME).

[0163] Example 8

[0164] S1. Method for loading silver (copper) nanoparticles on diatomaceous earth:

[0165] (1) Pretreatment of diatomaceous earth

[0166] Weigh a certain amount of diatomaceous earth, calcine it in a muffle furnace at 400°C for 2 h, and then cool it to room temperature in a desiccator for later use.

[0167] (2) Modification of diatomite

[0168] Take 1 g of the treated diatomaceous earth and disperse it in 100 mL of toluene or ethanol and ultrasonicate for 30 min;

[0169] Take a round-bottom flask, add the above diatomaceous earth dispersion into the flask, then add 3 mL of 3-aminopropyltriethoxysilane dropwise, reflux at 80 ° C and magnetically stir for 15 h;

[0170] The diatomaceous earth dispersion after the above reaction was centrifuged and washed with ethanol and deionized water for three times, respectively, dried at 65° C., and properly stored.

[0171] (3) Nanosilver / copper ion loaded diatomaceous earth

[0172] Prepare 0.01 mol / L copper nitrate solution, 0.01 mol / L silver nitrate solution, and 0.025 mol / L sodium borohydride solution for later use;

[0173] Take 0.2 g of modified diatomaceous earth and disperse it in 100 mL of ethanol, and ultrasonicate for 100 min;

[0174] Take 5 mL of freshly prepared silver nitrate solution and 5 mL of copper nitrate and add them to the above ethanol solution. Shield from light and stir at room temperature to react for 120 minutes.

[0175] After 2 h, 0.02 g of PVP-K30 was dispersed in 50 mL of deionized water and then added dropwise to the reaction solution and stirred for 40 min;

[0176] Then, 10 mL of freshly prepared sodium borohydride solution was added dropwise to the reaction solution using a constant pressure funnel and reacted at room temperature for 15 min.

[0177] After the reaction is completed, the mixture is immediately centrifuged and the precipitate obtained by centrifugation is washed three times with ethanol and three times with deionized water to remove excess reducing agent and PVP; finally, the mixture is freeze-dried for 15 hours to obtain nanosilver / nanocopper-loaded diatomaceous earth (Ag / Cu@DME).

[0178] Example 9

[0179] S1. Method for loading silver (copper) nanoparticles on diatomaceous earth:

[0180] (1) Pretreatment of diatomaceous earth

[0181] Weigh a certain amount of diatomaceous earth, calcine it in a muffle furnace at 400°C for 2 h, and then cool it to room temperature in a desiccator for later use.

[0182] (2) Modification of diatomite

[0183] Take 1 g of the treated diatomaceous earth and disperse it in 100 mL of toluene or ethanol and ultrasonicate for 30 min;

[0184] Take a round-bottom flask, add the above diatomaceous earth dispersion into the flask, then add 3 mL of APTES3-aminopropyltriethoxysilane dropwise, reflux at 80 ° C and magnetically stir for 15 h;

[0185] The diatomaceous earth dispersion after the above reaction was centrifuged and washed with ethanol and deionized water for three times, respectively, dried at 65° C., and properly stored.

[0186] (3) Nanosilver / copper ion loaded diatomaceous earth

[0187] Prepare 0.01 mol / L copper nitrate solution, 0.01 mol / L silver nitrate solution, and 0.025 mol / L sodium borohydride solution for later use;

[0188] Take 0.2 g of modified diatomaceous earth and disperse it in 100 mL of ethanol, and ultrasonicate for 100 min;

[0189] Take 20 mL of freshly prepared silver nitrate solution and 20 mL of copper nitrate and add them to the above ethanol solution. Shield from light and stir at room temperature to react for 120 minutes.

[0190] After 2 h, 0.02 g of PVP-K30 was dispersed in 50 mL of deionized water and then added dropwise to the reaction solution and stirred for 40 min;

[0191] Then, 10 mL of freshly prepared sodium borohydride solution was added dropwise to the reaction solution using a constant pressure funnel and reacted at room temperature for 15 min.

[0192] After the reaction is completed, the mixture is immediately centrifuged and the precipitate obtained by centrifugation is washed three times with ethanol and deionized water to remove excess reducing agent and PVP; finally, the mixture is freeze-dried for 15 hours to obtain nanosilver / nanocopper-loaded diatomaceous earth (Ag / Cu@DME).

[0193] Example 10

[0194] S1. Method for loading silver (copper) nanoparticles on diatomaceous earth:

[0195] (1) Pretreatment of diatomaceous earth

[0196] Weigh a certain amount of diatomaceous earth, calcine it in a muffle furnace at 400°C for 2 h, and then cool it to room temperature in a desiccator for later use.

[0197] (2) Modification of diatomite

[0198] Take 1 g of the treated diatomaceous earth and disperse it in 100 mL of toluene or ethanol and ultrasonicate for 30 min;

[0199] Take a round-bottom flask, add the above diatomaceous earth dispersion into the flask, then add 3 mL of 3-aminopropyltriethoxysilane dropwise, reflux at 80 ° C and magnetically stir for 15 h;

[0200] The diatomaceous earth dispersion after the above reaction was centrifuged and washed with ethanol and deionized water for three times, respectively, dried at 65° C., and properly stored.

[0201] (3) Nanosilver / copper ion loaded diatomaceous earth

[0202] Prepare 0.01 mol / L copper nitrate solution, 0.01 mol / L silver nitrate solution, and 0.025 mol / L sodium borohydride solution for later use;

[0203] Take 0.2 g of modified diatomaceous earth and disperse it in 100 mL of ethanol, and ultrasonicate for 100 min;

[0204] Take 10 mL of freshly prepared silver nitrate solution and 10 mL of copper nitrate and add them to the above ethanol solution. Shield from light and stir at room temperature to react for 120 minutes.

[0205] After 2 h, 0.02 g of PVP-K30 was dispersed in 10 mL of deionized water and then added dropwise to the reaction solution and stirred for 40 min;

[0206] Then, 10 mL of freshly prepared sodium borohydride solution was added dropwise to the reaction solution using a constant pressure funnel and reacted at room temperature for 15 min.

[0207] After the reaction is completed, the mixture is immediately centrifuged and the precipitate obtained by centrifugation is washed three times with ethanol and deionized water to remove excess reducing agent and PVP; finally, the mixture is freeze-dried for 15 hours to obtain nanosilver / nanocopper-loaded diatomaceous earth (Ag / Cu@DME).

[0208] S2. Preparation method of amino-modified diatomite:

[0209] 1 g of calcined diatomaceous earth was weighed and placed in 10 mL of deionized water and stirred to form a suspension. 2.4 mmol of 3-aminopropylmethyldimethoxysilane was then added and stirred at a constant temperature of 60°C for 2 h. The product was washed, filtered, dried at a constant temperature of 60°C, and bagged for later use. It was named NH@DME.

[0210] S3. Composite of new materials with antibacterial and formaldehyde adsorption properties:

[0211] The nanosilver / nanocopper loaded diatomaceous earth (Ag / Cu@DME) prepared in S1 and the amino-modified diatomaceous earth NH@DME in S2 were mixed evenly in a ratio of 1:1 to obtain a new multifunctional material with both antibacterial and formaldehyde adsorption properties.

[0212] Comparative Example 2

[0213] S1. Method for loading silver (copper) nanoparticles with silica particles:

[0214] (1) Modification of silica particles

[0215] Take 1 g of the treated silica and disperse it in 100 mL of toluene or ethanol and ultrasonicate for 30 min;

[0216] Take a round-bottom flask, add the above silica particle dispersion into the flask, then add 3 mL of 3-aminopropyltriethoxysilane dropwise, reflux at 80°C with magnetic stirring for 15 h;

[0217] The silica dispersion after the reaction was centrifuged and washed with ethanol and deionized water for three times, dried at 65° C., and properly stored.

[0218] (2) Silica loaded with nanosilver / copper ions

[0219] Prepare 0.01 mol / L copper nitrate solution, 0.01 mol / L silver nitrate solution, and 0.025 mol / L sodium borohydride solution for later use;

[0220] Take 0.2 g of the modified silica and disperse it in 100 mL of ethanol, and ultrasonicate for 100 min;

[0221] Take 10 mL of freshly prepared silver nitrate solution and 10 mL of copper nitrate and add them to the above ethanol solution. Shield from light and stir at room temperature to react for 120 minutes.

[0222] After 2 h, 0.02 g of PVP-K30 was dispersed in 50 mL of deionized water and then added dropwise to the reaction solution and stirred for 40 min;

[0223] Then, 10 mL of freshly prepared sodium borohydride solution was added dropwise to the reaction solution using a constant pressure funnel and reacted at room temperature for 15 min.

[0224] After the reaction is completed, the mixture is centrifuged immediately and the precipitate obtained by centrifugation is washed three times with ethanol and deionized water to remove excess reducing agent and PVP; finally, the mixture is freeze-dried for 15 hours to obtain nanosilver / nanocopper-loaded silica (Ag / Cu@SiO2).

[0225] Examples 5-10 and Comparative Example 2 were tested using the following method

[0226] Antibacterial and formaldehyde treatment performance test methods:

[0227] T1: Antibacterial performance test

[0228] (1) Take 0.2 g of the sterilized test sample (e.g., Ag / Cu@DME) and the control sample (e.g., diatomaceous earth powder without nanoparticles), add them to 4.5 mL of sterilized PBS solution, and add 0.2 mL of Escherichia coli liquid culture dilution to each, shake well, and place in a 36°C constant temperature incubator for 6 h.

[0229] (2) Use a pipette to take 0.5 mL of the cultured bacterial solution and drip it into 4.5 mL of sterile phosphate buffer along the wall of the tube. The tip of the pipette should not touch the diluent in the test tube. Shake the test tube to mix evenly to obtain a 1:10 dilution.

[0230] (3) Take another 1 mL sterile pipette and make 10-fold incremental dilutions according to the above procedure. After each incremental dilution, use a 1 mL sterile pipette. Select three appropriate dilutions. While making 10-fold incremental dilutions, use the pipette that has been used to transfer 0.1 mL of the sample to the prepared nutrient agar medium and spread it evenly with a triangular spreading rod. Prepare two culture dishes for each dilution as replicates.

[0231] (4) Place the evenly coated culture dish in a constant temperature incubator at 36°C. After incubation for 18 to 24 hours, remove the dish and count the colonies. The average value of the duplicate culture dishes is used as the number of E. coli colonies at that dilution. (6) Calculate the sterilization rate.

[0232] T2: Test of formaldehyde adsorption performance:

[0233] The same mass of the test materials obtained above (e.g., the test sample is diatomaceous earth modified with amino-containing silane coupling agent NH@DME and the control sample is unmodified diatomaceous earth) is placed in a formaldehyde concentration of 5 μL / m 3 In two experimental chambers with a volume of 1.5 cubic meters, the formaldehyde concentration in the two experimental chambers was measured after 12 hours of adsorption.

[0234] Table 2 Comparison of antibacterial and formaldehyde treatment properties of diatomaceous earth

[0235]

[0236] As can be seen from Table 2 above, in Example 7, the antibacterial effect of diatomaceous earth loaded silver-copper composite nanoparticles is significantly better than the antibacterial effect of diatomaceous earth loaded with a metal nanoparticle in Example 5 and Example 6. Comparing Example 7, Example 8, and Example 9, the amount of diatomaceous earth loaded with silver-copper nanoparticles will affect the antibacterial effect of the material. Therefore, in the preparation of the material, the loading amount of nano silver-copper particles should be adjusted according to actual use requirements to ensure the antibacterial effect of the material. Comparing Example 7 and Example 10, in Example 10, the modified diatomaceous earth was compounded on the basis of Example 7. The composite material has good formaldehyde adsorption performance. In addition to the physical adsorption of formaldehyde by the diatomaceous earth pores, on the other hand, due to the chemical reaction between the amino group of the modified diatomaceous earth and formaldehyde, a relatively stable compound containing an imine group is formed, thereby achieving stable adsorption of formaldehyde.

[0237] Since bacteria double in number every 20 to 30 minutes, killing a single species with a single method leaves room for other bacteria to grow, resulting in an ineffective reduction in the total bacterial population and failure to achieve the desired sterilization effect. Therefore, silver nanoparticles and copper nanoparticles are used in appropriate ratios for sterilization. Although the difference in effectiveness may appear to be only a few percentage points or even a fraction of a percentage point, this difference is not a simple one-plus-one addition. Rather, it is achieved through the synergistic killing of different types of bacteria by the different sterilization mechanisms of nanosilver and nanocopper. Therefore, this is a combined invention.

[0238] Existing formaldehyde removal materials suitable for air purifiers can only sterilize by adsorption. In order to further remove bacteria in the air, diatomaceous earth modified with a Class A silane coupling agent is used to support nanosilver / nanocopper and mixed with diatomaceous earth modified with a Class B silane coupling agent. This can simultaneously sterilize and purify formaldehyde in indoor air through the mechanism that formaldehyde easily reacts with amino groups to form azomethine and Schiff base chemical structures. This can not only specifically adsorb aldehyde pollutants, but also ensure the stability of adsorption to a certain extent.

[0239] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a formaldehyde-removing and antibacterial air purification composite material, characterized in that: The method comprises the following steps: calcining diatomite at 200-600°C for 60-180 minutes, adding the diatomite into deionized water and stirring to form a suspension, adding a type B silane coupling agent, stirring the suspension at a constant temperature of T5°C for t7 hours, washing the suspension, filtering the suspension, and drying the suspension at a constant temperature of T6°C; The type B silane coupling agent modified diatomaceous earth prepared by the above preparation method is mixed with the antibacterial material in a mixing ratio of 2:7 to 7:2; T5°C is 50°C to 70°C, t7 h is 1 to 3 h, T6°C is 50°C to 70°C, the ratio of diatomaceous earth: deionized water: type B silane coupling agent is 1 g: 10 mL: 2.4 mmol, and the type B silane coupling agent includes 3-aminopropylmethyldimethoxysilane; The antibacterial material is prepared by the following steps: Calcining diatomaceous earth at 200° C. to 600° C. for 60 min to 180 min, then modifying the calcined diatomaceous earth with a type A silane coupling agent, and loading silver nanoparticles and copper nanoparticles on the diatomaceous earth modified with the type A silane coupling agent, wherein the type A silane coupling agent includes 3-aminopropyltriethoxysilane; The specific steps of modifying the calcined diatomite with a silane coupling agent include: adding the calcined diatomite to an S1 solvent and ultrasonicating for 1 minute to form an S1 solution of the calcined diatomite; adding a type A silane coupling agent to the S1 solution of the calcined diatomite, refluxing at T1°C and magnetically stirring for 2 hours, washing the precipitate and drying at T2°C to obtain the type A silane coupling agent-modified diatomite; The S1 solvent is toluene or ethanol, t1 min is 30 min to 60 min, T1°C is 80°C to 85°C, t2 h is 10 h to 20 h, T2°C is 60°C to 80°C, and the Class A silane coupling agent includes 3-aminopropyltriethoxysilane; the washing and precipitation refers to the product after reflux and stirring, centrifuging and washing the precipitate with ethanol and deionized water three times respectively, and drying at T2 to obtain the Class A silane coupling agent modified diatomaceous earth.

2. The method for preparing the formaldehyde-removing and antibacterial air-purifying composite material according to claim 1, wherein: The ratio of the calcined diatomaceous earth: S1 solvent: type A silane coupling agent is 1 g: 100 mL: (1 mL to 3 mL).

3. The method for preparing the formaldehyde-removing and antibacterial air-purifying composite material according to claim 1, wherein: The steps of loading silver nanoparticles and copper nanoparticles are as follows: dispersing diatomaceous earth modified by a type A silane coupling agent with an S2 solvent, ultrasonicating for 3 minutes, adding a silver nitrate solution and a copper nitrate solution, stirring and reacting at T3°C for 2 minutes under light shielding, adding the S3 solution dropwise, stirring and mixing for 2 minutes, then adding a sodium borohydride solution dropwise, reacting at T4°C for 2 minutes, centrifuging and washing, and freeze-drying to obtain the type A silane coupling agent-modified diatomaceous earth loaded with nano-silver and nano-copper; The S2 solvent is ethanol, the S3 solution is a polyvinylpyrrolidone aqueous solution, t3 min is 60 min to 120 min, T3 ° C is 20 ° C to 25 ° C, t4 min is 80 min to 150 min, t5 min is 20 min to 60 min, T4 ° C is 20 ° C to 25 ° C, and t6 min is 10 min to 20 min; The ratio of the solute mass of the Class A silane coupling agent modified diatomaceous earth: S2 solvent: S3 solution is 40 mg: 20 mL: 4 mg, the ratio of the concentration of silver nitrate solution: the concentration of copper nitrate solution: the concentration of sodium borohydride solution is 0.002 mol / L: 0.002 mol / L: 0.005 mol / L, the ratio of the volume of silver nitrate solution: the volume of copper nitrate solution: the volume of sodium borohydride solution: the volume of S3 solution is 5-20 mL: 5-20 mL: 10 mL: 10-50 mL, and the ratio of the volume of S2 solvent: the volume of S3 solution is 20-100 mL: 10-50 mL.

4. A method for preparing the formaldehyde-removing and antibacterial air-purifying composite material according to claim 1, characterized in that: The mixing ratio of type B silane coupling agent modified diatomaceous earth and antibacterial material is 1:

1.

5. A formaldehyde-removing and antibacterial air-purifying composite material prepared by the preparation method according to any one of claims 1 to 4.

Images