Sterilizing and air purifying filter material

Abstract

The invention discloses a sterilizing and air purifying filtering material which comprises an outermost layer, a secondary outer layer, a middle layer and an innermost layer, and the outermost layer is composed of a stainless steel punching net and a nylon net; the secondary outer layer adopts a purification filter screen, and the purification filter screen comprises the following components by weight: polypropylene, electret master batch, an antioxidant, an ultraviolet light absorber, a lubricant, a nanoparticle reinforcing material and a silver ion solution; the middle layer adopts a photocatalyst-loaded glass fiber mat, and the photocatalyst-loaded glass fiber mat comprises a glass fiber mat, a mesoporous molecular sieve, a photocatalytic material and an antibacterial agent; the innermost layer is made of a thermoplastic polyurethane elastomer. The invention relates to the technical field of air purification. The filter material provided by the invention can bear the pressure generated by air flow and the influence of external environmental factors, is not easy to layer, deform and the like, and ensures the durability and stability of the material performance, thereby prolonging the service life of the product and reducing the frequent replacement of the filter material.

Description

Technical Field

[0001] The invention relates to the technical field of air purification, and in particular to a sterilizing air purification filter material. Background Art

[0002] With the improvement of people's living standards and the increasing attention paid to health and environmental quality, the demand for air purification products is growing. Among many air purification devices, air purification filter materials are the core components, and their performance directly determines the effect of air purification.

[0003] At present, the common air purification filter materials on the market have many shortcomings. Traditional filter materials, such as ordinary non-woven filters or metal filters, mainly rely on physical interception to filter particulate matter in the air. The filtration efficiency is low for tiny particles, especially those with a diameter of less than 1 micron, and it is difficult to effectively remove microorganisms such as bacteria and viruses and harmful gaseous pollutants in the air.

[0004] To solve the above problems, some existing technologies have tried to improve the materials, such as adding antibacterial agents to the filter or using a composite structure. However, these improvements often have the problem of insufficient synergy, and each component fails to give full play to its advantages, resulting in air purification filter materials being difficult to achieve an ideal balance in terms of filtration efficiency, sterilization ability, service life, and cost control.

[0005] In summary, the development of a sterilizing air purification filter material that can efficiently filter tiny particles, effectively kill bacteria and viruses, and permanently decompose harmful gaseous pollutants at a reasonable cost has important practical significance and market demand. The present invention aims to overcome the shortcomings of the prior art by carefully selecting and optimizing the combination of materials for each layer and innovating the preparation process, and to provide a sterilizing air purification filter material with better performance. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a sterilizing air purification filter material, comprising an outermost layer, a second outermost layer, an intermediate layer and an innermost layer, wherein the outermost layer is composed of a stainless steel perforated mesh and a nylon mesh; The secondary outer layer adopts a purification filter, which comprises the following weight components: 85-92 weight parts of polypropylene, 8-15 weight parts of electret masterbatch, 0.1-0.5 weight parts of antioxidant, 0.1-0.3 weight parts of ultraviolet absorber, 0.5-1.5 weight parts of lubricant, 0-3 weight parts of nanoparticle reinforcement material and 2-10 weight parts of silver ion solution; The antioxidant is antioxidant 1010, the ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, the lubricant is pentaerythritol stearate, and the nano-particle reinforcement material is nano-alumina.

[0007] The middle layer is made of glass fiber felt loaded with photocatalyst, and the glass fiber felt loaded with photocatalyst includes glass fiber felt, mesoporous molecular sieve, photocatalytic material and antibacterial agent; The innermost layer is made of thermoplastic polyurethane elastomer.

[0008] Preferably, the preparation method of the purification filter comprises the following steps: Step 1: Weigh polypropylene, electret masterbatch, antioxidant, ultraviolet absorber, lubricant and nanoparticle reinforcement material according to weight parts, dry the polypropylene to remove moisture, then add all the materials into a high-speed mixer, stir and mix them thoroughly to form a mixed material; Step 2: Add the mixed material into a twin-screw extruder, heat and melt, fully plasticize, and then extrude it through a die head to form a continuous polypropylene melt stream, which is stretched and refined into fibers under the action of a high-speed hot air flow and sprayed onto a rotating drum to form a melt-blown fiber felt, which is cut and hot-pressed as needed to form a polypropylene melt-blown filter element; In the step 2, the heating and melting temperature is set to 180-260°C, the aperture of the die head is set to 0.1-0.5 mm, the speed of the high-speed hot air flow is set to 100-300 m / s, and the temperature is set to 250-350°C; Step 3: Place the polypropylene melt-blown filter element between the electrodes of the corona charging device, apply high voltage direct current to ionize the air between the electrodes, generate a large number of charged particles, and charge the polypropylene melt-blown filter element under the action of the electric field, so that it is charged to form an electrostatic electret filter material; In the step 3, the electrode spacing is set to 5-15 mm, the high voltage direct current is set to 10-30 KV, and the charging time is set to 1-5 min; Step 4: Pour an appropriate amount of silver ion solution into the immersion tank, immerse the prepared electrostatic electret filter material completely in the solution, soak for a certain period of time to allow the silver ions to be evenly adsorbed on the filter, then take out the filter, drain, dry and other processes to remove excess solution to complete the purification of the filter.

[0009] Preferably, the method for preparing the photocatalyst-loaded glass fiber mat comprises the following steps: Step 1: Cut, clean and dry the fiberglass felt; Step 2: dissolving tetraethyl orthosilicate, hexadecyltrimethylammonium bromide and sodium hydroxide in water, stirring to form a mixed solution, transferring the solution to a hydrothermal reactor after aging reaction, and obtaining a mesoporous molecular sieve by centrifugation, washing and drying after the reaction is completed; In the step 2, the aging reaction temperature is set to 35-45°C and the time is set to 12-24h; In the step 2, the temperature in the reactor is set to 100-150° C., and the time is set to 24-72 hours; Step 3: Mix the mesoporous molecular sieve and the glass fiber felt in proportion, and use ultrasonic dispersion to make the mesoporous molecular sieve evenly adhere to the surface and pores of the glass fiber felt to form a basic adsorption material; Step 4: Use butyl titanate as a titanium source and ethanol as a solvent, add an appropriate amount of ferric nitrate, stir evenly to form a transparent solution, immerse the basic adsorbent material in the solution, take it out after sufficient immersion, dry it, and calcine it to form a doped and modified titanium dioxide nanotube array loaded on the basic adsorbent material; In the step 4, the drying temperature is set to 60-80°C; In the step 4, the calcination temperature is set to 400-600°C and the time is set to 2-4h; Step 5: Dissolve bismuth nitrate and sodium tungstate in nitric acid in a stoichiometric ratio, stir evenly, and then immerse the basic adsorption material loaded with the modified titanium dioxide nanotube array into the solution, and grow bismuth tungstate in situ on the surface of the material through a hydrothermal reaction to form a structure in which the modified titanium dioxide nanotube array and the bismuth-based photocatalyst are synergistically loaded; In the step 5, the hydrothermal reaction temperature is set to 160-180° C., and the time is set to 12-24 hours; In the step 5, the weight ratio of the titanium dioxide nanotube array to the bismuth-based photocatalyst is 65:35; Step six: dissolve the silver ion antibacterial agent in a solvent, and then immerse the glass fiber felt loaded with the photocatalytic material into the solution. Through the processes of immersion and drying, the antibacterial agent is evenly distributed in the material to form a glass fiber felt loaded with the photocatalyst.

[0010] The present invention provides a sterilizing air purification filter material. It has the following beneficial effects: 1. The outermost filter is composed of a stainless steel perforated mesh and a nylon mesh. The stainless steel perforated mesh has a larger aperture, which can initially intercept large impurities such as dust clumps and insect debris to prevent them from entering the subsequent filter layer, effectively reducing the burden of subsequent filtration. The nylon mesh further filters smaller impurities such as hair. Through the preliminary screening of these two layers of filters, larger visible impurities can be effectively filtered. The composite HEPA filter of the second outer layer, in which the polypropylene melt-blown filter element uses its fiber structure to filter particles within a certain particle size range through mechanical interception and Brownian motion; the electrostatic electret filter material relies on electrostatic adsorption to capture extremely small particles, especially for small particles of 0.3 microns and above. It has extremely high filtration efficiency. This multi-level filtration structure accurately intercepts particles of different sizes from large to small, greatly improving the overall filtration efficiency of particles in the air.

[0011] 2. The combination of polypropylene melt-blown filter element and electrostatic electret filter material enables the filter to achieve high-efficiency filtration while maintaining low air resistance. The pore structure of the polypropylene melt-blown filter element itself ensures the smooth passage of air, while the electrostatic electret filter material filters particulate matter through electrostatic adsorption, without excessively reducing the pores to improve the filtration accuracy. Therefore, while ensuring efficient filtration of tiny particles, it ensures that the ventilation volume is not greatly affected, maintains a good purification effect, and does not reduce the air purification efficiency due to excessive resistance.

[0012] 3. Silver ion antibacterial agent or quaternary ammonium salt antibacterial agent is added to the glass fiber felt loaded with photocatalyst in the middle layer, which further enhances the bactericidal ability. At the same time, the loaded modified titanium dioxide nanotube array and bismuth-based photocatalyst will produce strong oxidizing free radicals such as hydroxyl free radicals and superoxide free radicals under light conditions. These free radicals can not only decompose harmful gases, but also directly act on the cell walls, cell membranes and internal structures of bacteria and viruses to kill them. The free radicals generated by photocatalysis and the antibacterial agent work together to greatly enhance the killing effect of microorganisms in the air, ensuring that the output air reaches a highly clean and sterile state.

[0013] 4. The modified titanium dioxide nanotube array loaded on the glass fiber felt works synergistically with the bismuth-based photocatalyst to generate photogenerated carriers under light, thereby generating active species with strong oxidizing properties. These active species can oxidize and decompose harmful gases adsorbed by the glass fiber into harmless substances such as carbon dioxide and water, thereby achieving regeneration. The modified titanium dioxide nanotube array is modified by element doping, which broadens the absorption range of light and improves the utilization rate of visible light; the bismuth-based photocatalyst forms a heterojunction with titanium dioxide, effectively promoting the transfer and separation of photogenerated carriers, and further improving the photocatalytic efficiency. This synergistic effect of adsorption and photocatalysis enables the continuous decomposition of harmful gases, ensuring the continuity and high efficiency of air purification.

[0014] 5. The entire filter material adopts a four-layer structure design, and each layer is closely matched and supports each other. This structural design enables the material to withstand the pressure generated by air flow and the influence of external environmental factors during long-term use, and is not prone to stratification, deformation and other problems, ensuring the durability and stability of material performance, thereby extending the service life of the product and reducing the cost and trouble of frequent replacement of filter materials. DETAILED DESCRIPTION

[0015] The following specific embodiments further describe the present invention in detail. The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

[0016] Embodiment 1, a sterilizing air purification filter material, comprising an outermost layer, a second outermost layer, a middle layer and an innermost layer, wherein the outermost layer is composed of a stainless steel perforated mesh and a nylon mesh; The secondary outer layer adopts a purification filter, which includes the following weight components: 85 weight parts of polypropylene, 8 weight parts of electret masterbatch, 0.1 weight parts of antioxidant, 0.1 weight parts of ultraviolet absorber, 0.5 weight parts of lubricant and 2 weight parts of silver ion solution; The middle layer adopts glass fiber felt loaded with photocatalyst, and the glass fiber felt loaded with photocatalyst includes glass fiber felt, mesoporous molecular sieve, photocatalytic material and antibacterial agent; The innermost layer is made of thermoplastic polyurethane elastomer.

[0017] The antioxidant is antioxidant 1010, the ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, the lubricant is pentaerythritol stearate, and the nano-particle reinforcing material is nano-alumina.

[0018] Embodiment 2, a sterilizing air purification filter material, comprising an outermost layer, a second outermost layer, a middle layer and an innermost layer, wherein the outermost layer is composed of a stainless steel perforated mesh and a nylon mesh; The secondary outer layer adopts a purification filter, which includes the following weight components: 88.5 weight parts of polypropylene, 11.5 weight parts of electret masterbatch, 0.3 weight parts of antioxidant, 0.2 weight parts of ultraviolet absorber, 1 weight part of lubricant, 1.5 weight parts of nanoparticle reinforcement material and 6 weight parts of silver ion solution; The middle layer adopts glass fiber felt loaded with photocatalyst, and the glass fiber felt loaded with photocatalyst includes glass fiber felt, mesoporous molecular sieve, photocatalytic material and antibacterial agent; The innermost layer is made of thermoplastic polyurethane elastomer.

[0019] The antioxidant is antioxidant 1010, the ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, the lubricant is pentaerythritol stearate, and the nano-particle reinforcing material is nano-alumina.

[0020] Embodiment 3, a sterilizing air purification filter material, comprising an outermost layer, a second outermost layer, a middle layer and an innermost layer, wherein the outermost layer is composed of a stainless steel perforated mesh and a nylon mesh; The secondary outer layer adopts a purification filter, which includes the following weight components: 92 parts by weight of polypropylene, 15 parts by weight of electret masterbatch, 0.5 parts by weight of antioxidant, 0.3 parts by weight of ultraviolet absorber, 1.5 parts by weight of lubricant, 3 parts by weight of nanoparticle reinforcement material and 10 parts by weight of silver ion solution; The middle layer adopts glass fiber felt loaded with photocatalyst, and the glass fiber felt loaded with photocatalyst includes glass fiber felt, mesoporous molecular sieve, photocatalytic material and antibacterial agent; The innermost layer is made of thermoplastic polyurethane elastomer.

[0021] The antioxidant is antioxidant 1010, the ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, the lubricant is pentaerythritol stearate, and the nano-particle reinforcing material is nano-alumina.

[0022] In Example 1, Example 2 and Example 3, the preparation method of the purification filter screen comprises the following steps: Step 1: Weigh polypropylene, electret masterbatch, antioxidant, ultraviolet absorber, lubricant and nanoparticle reinforcement material according to weight parts, dry the polypropylene to remove moisture, then add all the materials into a high-speed mixer, stir and mix them thoroughly to form a mixed material; Step 2: Add the mixed material into a twin-screw extruder, heat and melt, fully plasticize, and then extrude it through a die head to form a continuous polypropylene melt stream, which is stretched and refined into fibers under the action of a high-speed hot air flow and sprayed onto a rotating drum to form a melt-blown fiber felt, which is cut and hot-pressed as needed to form a polypropylene melt-blown filter element; In step 2, the heating and melting temperature is set to 180-260°C, the aperture of the die head is set to 0.1-0.5 mm, the speed of the high-speed hot air flow is set to 100-300 m / s, and the temperature is set to 250-350°C; Step 3: Place the polypropylene melt-blown filter element between the electrodes of the corona charging device, apply high voltage direct current to ionize the air between the electrodes, generate a large number of charged particles, and charge the polypropylene melt-blown filter element under the action of the electric field, so that it is charged to form an electrostatic electret filter material; In step 3, the electrode spacing is set to 5-15 mm, the high voltage direct current is set to 10-30 KV, and the charging time is set to 1-5 min; Step 4: Pour an appropriate amount of silver ion solution into the immersion tank, immerse the prepared electrostatic electret filter material completely in the solution, soak for a certain period of time to allow the silver ions to be evenly adsorbed on the filter, then take out the filter, drain, dry and other processes to remove excess solution to complete the purification of the filter.

[0023] The preparation method of the glass fiber mat loaded with photocatalyst comprises the following steps: Step 1: Cut, clean and dry the fiberglass felt; Step 2: dissolving tetraethyl orthosilicate, hexadecyltrimethylammonium bromide and sodium hydroxide in water, stirring to form a mixed solution, transferring the solution to a hydrothermal reactor after aging reaction, and obtaining a mesoporous molecular sieve by centrifugation, washing and drying after the reaction is completed; The aging reaction temperature is set to 35-45°C and the time is set to 12-24h; The temperature in the reactor is set to 100-150°C and the time is set to 24-72h; Step 3: Mix the mesoporous molecular sieve and the glass fiber felt in proportion, and use ultrasonic dispersion to make the mesoporous molecular sieve evenly adhere to the surface and pores of the glass fiber felt to form a basic adsorption material; Step 4: Use butyl titanate as a titanium source and ethanol as a solvent, add an appropriate amount of ferric nitrate, stir evenly to form a transparent solution, immerse the basic adsorbent material in the solution, take it out after sufficient immersion, dry it, and calcine it to form a doped and modified titanium dioxide nanotube array loaded on the basic adsorbent material; In step 4, the drying temperature is set to 60-80°C; In step 4, the calcination temperature is set to 400-600°C and the time is set to 2-4h; Step 5: Dissolve bismuth nitrate and sodium tungstate in nitric acid in a stoichiometric ratio, stir evenly, and then immerse the basic adsorption material loaded with the modified titanium dioxide nanotube array into the solution, and grow bismuth tungstate in situ on the surface of the material through a hydrothermal reaction to form a structure in which the modified titanium dioxide nanotube array and the bismuth-based photocatalyst are synergistically loaded; In step 5, the hydrothermal reaction temperature is set to 160-180°C and the time is set to 12-24h; In step 5, the weight ratio of the titanium dioxide nanotube array to the bismuth-based photocatalyst is 65:35; Step six: dissolve the silver ion antibacterial agent in a solvent, and then immerse the glass fiber felt loaded with the photocatalytic material into the solution. Through the processes of immersion and drying, the antibacterial agent is evenly distributed in the material to form a glass fiber felt loaded with the photocatalyst.

[0024] The performance of the materials prepared according to the above examples is compared, and the results are as follows: By comparing the material properties of Example 1, Example 2 and Example 3, it can be seen that with the increase of components such as electret masterbatch, nanoparticle reinforcement material, silver ion solution, antioxidant and ultraviolet absorber, the material shows a significant improvement trend in multiple key performance indicators. In terms of filtration efficiency, the filtration efficiency of particles of 0.3 microns and above is increased from about 95% in Example 1 to about 98% in Example 3, thanks to the enhancement of electrostatic adsorption and overall structural stability. The mechanical strength is greatly improved, and the tensile strength jumps from about 30MPa to about 40MPa, and nano-alumina plays a key enhancement role. The antibacterial performance is also greatly improved, and the killing rate of Escherichia coli has increased from about 90% to about 98%, which is due to the increase in the concentration of silver ion solution and the synergistic effect with other antibacterial agents. The anti-aging performance is excellent, and the performance retention rate after 1000 hours of simulated light is increased from about 80% to about 90%, thanks to the increase in the dosage of antioxidants and ultraviolet absorbers. In addition, the ability to decompose harmful gases is significantly enhanced, and the decomposition rate of formaldehyde is increased from about 60% to about 80%, which is due to the optimization of the loading amount and synergy of the modified titanium dioxide nanotube array and bismuth-based photocatalyst.

[0025] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention are implemented according to the conventional means in the field unless otherwise specified and limited.

Claims

1. A sterilizing air purification filter material, characterized in that: It includes an outermost layer, a second outermost layer, a middle layer and an innermost layer, wherein the outermost layer is composed of a stainless steel perforated mesh and a nylon mesh; The secondary outer layer adopts a purification filter, which comprises the following weight components: 85-92 weight parts of polypropylene, 8-15 weight parts of electret masterbatch, 0.1-0.5 weight parts of antioxidant, 0.1-0.3 weight parts of ultraviolet absorber, 0.5-1.5 weight parts of lubricant, 0-3 weight parts of nanoparticle reinforcement material and 2-10 weight parts of silver ion solution; The middle layer is made of glass fiber felt loaded with photocatalyst, and the glass fiber felt loaded with photocatalyst includes glass fiber felt, mesoporous molecular sieve, photocatalytic material and antibacterial agent; The innermost layer is made of thermoplastic polyurethane elastomer.

2. A sterilizing air purification filter material according to claim 1, characterized in that: The antioxidant is antioxidant 1010, the ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, the lubricant is pentaerythritol stearate, and the nano-particle reinforcement material is nano-alumina.

3. The sterilizing air purification filter material according to claim 1, characterized in that: The preparation method of the purification filter comprises the following steps: Step 1: Weigh polypropylene, electret masterbatch, antioxidant, ultraviolet absorber, lubricant and nanoparticle reinforcement material according to weight parts, dry the polypropylene to remove moisture, then add all the materials into a high-speed mixer, stir and mix them thoroughly to form a mixed material; Step 2: Add the mixed material into a twin-screw extruder, heat and melt, fully plasticize, and then extrude it through a die head to form a continuous polypropylene melt stream, which is stretched and refined into fibers under the action of a high-speed hot air flow and sprayed onto a rotating drum to form a melt-blown fiber felt, which is cut and hot-pressed as needed to form a polypropylene melt-blown filter element; Step 3: Place the polypropylene melt-blown filter element between the electrodes of the corona charging device, apply high voltage direct current to ionize the air between the electrodes, generate a large number of charged particles, and charge the polypropylene melt-blown filter element under the action of the electric field, so that it is charged to form an electrostatic electret filter material; Step 4: Pour an appropriate amount of silver ion solution into the immersion tank, immerse the prepared electrostatic electret filter material completely in the solution, soak for a certain period of time to allow the silver ions to be evenly adsorbed on the filter, then take out the filter, drain, dry and other processes to remove excess solution to complete the purification of the filter.

4. A sterilizing air purification filter material according to claim 3, characterized in that: In the step 2, the heating and melting temperature is set to 180-260°C, the aperture of the die head is set to 0.1-0.5 mm, the speed of the high-speed hot air flow is set to 100-300 m / s, and the temperature is set to 250-350°C.

5. The sterilizing air purification filter material according to claim 3, characterized in that: In the step three, the electrode spacing is set to 5-15 mm, the high voltage direct current is set to 10-30 KV, and the charging time is set to 1-5 min.

6. The sterilizing air purification filter material according to claim 1, characterized in that: The method for preparing the photocatalyst-loaded glass fiber mat comprises the following steps: Step 1: Cut, clean and dry the fiberglass felt; Step 2: dissolving tetraethyl orthosilicate, hexadecyltrimethylammonium bromide and sodium hydroxide in water, stirring to form a mixed solution, transferring the solution to a hydrothermal reactor after aging reaction, and obtaining a mesoporous molecular sieve by centrifugation, washing and drying after the reaction is completed; Step 3: Mix the mesoporous molecular sieve and the glass fiber felt in proportion, and use ultrasonic dispersion to make the mesoporous molecular sieve evenly adhere to the surface and pores of the glass fiber felt to form a basic adsorption material; Step 4: Use butyl titanate as a titanium source and ethanol as a solvent, add an appropriate amount of ferric nitrate, stir evenly to form a transparent solution, immerse the basic adsorbent material in the solution, take it out after sufficient immersion, dry it, and calcine it to form a doped and modified titanium dioxide nanotube array loaded on the basic adsorbent material; Step 5: Dissolve bismuth nitrate and sodium tungstate in nitric acid in a stoichiometric ratio, stir evenly, and then immerse the basic adsorption material loaded with the modified titanium dioxide nanotube array into the solution, and grow bismuth tungstate in situ on the surface of the material through a hydrothermal reaction to form a structure in which the modified titanium dioxide nanotube array and the bismuth-based photocatalyst are synergistically loaded; Step six: dissolve the silver ion antibacterial agent in a solvent, and then immerse the glass fiber felt loaded with the photocatalytic material into the solution. Through the processes of immersion and drying, the antibacterial agent is evenly distributed in the material to form a glass fiber felt loaded with the photocatalyst.

7. A sterilizing air purification filter material according to claim 6, characterized in that: In the step 2, the aging reaction temperature is set to 35-45°C and the time is set to 12-24h; In the step 2, the temperature in the reaction kettle is set to 100-150° C., and the time is set to 24-72 hours.

8. The sterilizing air purification filter material according to claim 6, characterized in that: In the step 4, the drying temperature is set to 60-80°C; In the step 4, the calcination temperature is set to 400-600° C. and the calcination time is set to 2-4 hours.

9. The sterilizing air purification filter material according to claim 6, characterized in that: In the step 5, the hydrothermal reaction temperature is set to 160-180° C., and the time is set to 12-24 hours; In the step 5, the weight ratio of the titanium dioxide nanotube array to the bismuth-based photocatalyst is 65:35.

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