Silver nanowire / silk fibroin fiber / glass fiber composite filter paper and preparation method and application thereof

Abstract

The invention discloses silver nanowire / silk fibroin fiber / glass fiber composite filter paper and a preparation method and application thereof. The method comprises the following steps: with natural silkworm cocoons as raw materials, preparing multi-scale silk fibroin fibers from top to bottom by using a solvent method and a mechanical method; preparing a silver nanowire / silk fibroin fiber composite material through electrostatic assembly between the silver nanowire and the silk fibroin fiber; the silver nanowire-multi-scale silk fibroin fiber / glass fiber air filter paper is prepared from glass fibers serving as a filter framework and the silver nanowire / silk fibroin fibers through a wet papermaking process. The obtained silver nanowire-multi-scale silk fibroin fiber / glass fiber air filter paper has high strength, good toughness and excellent antibacterial performance, a cobweb-shaped filter network can be formed, and air pollutants such as fine particulate matter and biological aerosol can be effectively filtered out.

Description

Technical Field

[0001] The invention relates to the field of air filtration, and in particular to a preparation method and application of filter paper for antibacterial air filtration. Background Art

[0002] Glass fiber filter materials have been widely used as air filter materials internationally. Their main advantages include good moisture resistance, chemical resistance, heat resistance, high dust holding rate and anti-biological erosion stability. However, glass fiber also has some disadvantages, such as high brittleness, easy breakage, poor flexibility, etc. In addition, traditional glass fiber filter materials capture particles from polluted gases through their internal randomly interwoven fiber layers, but it is difficult to achieve a balance between filtration efficiency and pressure drop. In order to improve filtration efficiency, air permeability is usually sacrificed, resulting in a larger pressure drop. Therefore, regulating the microstructure of glass fiber filter paper to achieve good air resistance and filtration efficiency at the same time is the current technical key and industry trend in the development of glass fiber air filter paper.

[0003] As the basic component of natural silk fiber, multi-scale silk fibroin fiber not only has the advantages of natural abundance and mechanical toughness, but also has adjustable biodegradability and good biocompatibility, making it a potential functional material. At present, many related reports have shown that the silk fibroin fiber after natural cocoon degumming is completely dissolved to form regenerated multi-scale silk fibroin fiber, and the natural properties of silk fibroin fibrils are inevitably sacrificed in this process. Another method is to prepare aerogel by dissolving silk fibroin fiber, but its application is limited due to its low porosity, weak resilience and high brittleness. While maintaining the structural stability of silk fibroin fiber, the silk fibroin fiber is peeled into multi-scale silk fibroin fiber by solvent method and mechanical method, which can maintain good mechanical strength and toughness. Compared with regenerated silk fibroin solution, multi-scale silk fibroin fiber shows good natural toughness and complete fiber shape. Therefore, the use of multi-scale silk fibroin fiber to regulate the micro-nanopore structure in glass fiber filter material is expected to improve its folding resistance and wear resistance, and achieve an effective balance between high filtration efficiency and piezoresistance, thereby extending the life of the filter material.

[0004] In addition to organic pollutants and microparticles, the air also contains pathogenic bacteria, viruses and other microorganisms. The filter material will intercept microorganisms and accumulate on the filter material, feed on other organic pollutants, form colonies and enter the room with the airflow, causing secondary pollution. Silver nanowires have good broad-spectrum antibacterial properties. By electrostatically assembling silver nanowires with silk fibroin fibers, they can effectively provide antibacterial properties, increase the roughness of the fibers, and improve the filtration performance of the filter material without excessively affecting the air permeability of the material. This study used a top-down method to prepare silk fibers from natural cocoons into multi-scale silk fibroin fibers, and electrostatically assembled them with silver nanowires to obtain silver nanowire / silk fibroin antibacterial nanofibers. Due to steric hindrance and hydrogen bonding, the silver nanowire / silk fibroin antibacterial nanofibers spontaneously formed a spider web-like entanglement structure with the glass fiber. Therefore, the silver nanowire / silk fibroin fiber can achieve good flexibility and excellent antibacterial effect while giving the glass fiber filter material strength. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a method for preparing a silver nanowire / silk fibroin fiber / glass fiber composite filter paper and its application in air filtration.

[0006] The purpose of the present invention is to address the deficiencies of the prior art and provide an antibacterial air filter paper, specifically a silver nanowire / silk fibroin fiber / glass fiber composite filter paper with filtering performance and antibacterial performance.

[0007] The present invention also aims to provide a preparation method of the silver nanowire / silk fibroin fiber / glass fiber composite filter paper and its application in air filtration. The preparation method adopts a top-down method to prepare multi-scale silk fibroin fibers from silk fibers in natural silkworm cocoons, and electrostatically assembles them with silver nanowires to obtain silver nanowire-silk fibroin antibacterial nanofibers, which spontaneously form a spider web-like entanglement structure through steric hindrance and hydrogen bonding with glass fibers, thereby obtaining antibacterial air filter paper with high filtration performance and antibacterial performance.

[0008] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0009] The present invention uses multi-scale silk fibroin fibers to prepare antibacterial air filter paper, and uses a wet papermaking process to prepare air filter paper with a lasting antibacterial effect.

[0010] The silver nanowire / silk fibroin fiber / glass fiber composite filter paper and its preparation method provided by the present invention adopt a top-down method to prepare silk fibers in natural silk cocoons into multi-scale silk fibroin fibers, and electrostatically assemble them with silver nanowires to obtain silver nanowire-silk fibroin antibacterial nanofibers, which spontaneously form a spider web-like entanglement structure through steric hindrance and hydrogen bonding with glass fibers, thereby obtaining antibacterial air filter paper with high filtration performance and antibacterial performance.

[0011] The present invention provides a method for preparing a silver nanowire / silk fibroin fiber / glass fiber composite filter paper, comprising the following steps:

[0012] (1) washing, chopping and degumming natural silk cocoons to obtain crude silk fibroin fibers, swelling the obtained crude silk fibroin fibers by a solvent method, then crushing them by a mechanical method under alkaline conditions, and dialyzing them with deionized water to obtain a multi-scale silk fibroin fiber dispersion;

[0013] (2) using polypyrrolidone and ethylene glycol as a template and a reducing agent, dissolving polypyrrolidone in ethylene glycol, reducing silver nitrate in a high-temperature oil bath, and then fully washing with acetone and dispersing in deionized water to obtain a silver nanowire solution;

[0014] (3) under stirring, adding the silver nanowire solution described in step 2 to the multi-scale silk fibroin fiber dispersion described in step 1 to obtain a multi-scale silver nanowire / silk fibroin fiber dispersion by electrostatic assembly;

[0015] (4) dispersing glass fibers in an acidic aqueous solution to obtain a glass fiber aqueous dispersion, adding the multi-scale silver nanowire / silk fibroin fiber dispersion described in step 3 to the glass fiber aqueous dispersion, and stirring thoroughly to obtain a silver nanowire / silk fibroin fiber / glass fiber dispersion. The dispersion is subjected to a wet papermaking process to obtain a silver nanowire / silk fibroin fiber / glass fiber antibacterial air filter paper.

[0016] Furthermore, the cocoon fragments in step (1) are approximately 1-2 cm, the concentration of sodium bicarbonate used for degumming is 1%-2%, and the degumming time is 30 min-60 min.

[0017] Furthermore, in step (1), the scale of the multi-scale silk fibroin fiber is 100 nm-2 μm; the alkaline condition is 1%-5% sodium hydroxide solution; and the mechanical crushing time is 5 min-30 min.

[0018] Furthermore, in step (1), the solvent method is specifically as follows: preparing a ternary solution of water / anhydrous ethanol / calcium chloride with a molar ratio of 1:2:8 to 1:4:8, taking 2g to 4g of the degummed silk fibroin fiber and soaking it in the ternary solution, and soaking and swelling it for 24-48 hours.

[0019] Further, in step (2), in step (2), the mass percentage concentration of the silver nanowires is 1%-2%. The specific conditions of the high temperature oil bath are: 130-150°C; the concentration of the polypyrrolidone in ethylene glycol is 1.0-8.0 g / L, and the concentration of the silver nitrate in ethylene glycol is 5.0-10.0 g / L.

[0020] Furthermore, in step (3), the amount of the silver nanowire solution added to the multi-scale silk fibroin fiber dispersion is 5-10 ml, and the amount of the multi-scale silk fibroin fiber dispersion added is 50-100 ml.

[0021] Furthermore, in step (4), the mass percentage concentration of the silver nanowires / silk fibroin fibers is between 10% and 20%.

[0022] Furthermore, in step (4), the acidic aqueous solution is a 10%-20% sulfuric acid aqueous solution; the mass percentage concentration of the glass fiber aqueous dispersion is 0.05%-0.10%; the added amounts of the multi-scale silver nanowires / silk fibroin fibers and the glass fiber aqueous dispersion satisfy: the mass ratio of the multi-scale silver nanowires / silk fibroin fibers to the glass fiber aqueous dispersion is 10%-20%; and the drying temperature of the wet drying process is 90°C-95°C.

[0023] The present invention provides a silver nanowire / silk fibroin fiber / glass fiber antibacterial air filter paper prepared by the above-mentioned preparation method, which can effectively filter out 99% of PM2.5, bacteria and other air pollutants, and can kill bacteria to prevent bacteria from multiplying on the filter paper and causing secondary pollution.

[0024] The present invention provides a silver nanowire / silk fibroin fiber / glass fiber antibacterial air filter paper prepared by the above-mentioned preparation method, which can meet the requirements of antibacterial air filter paper.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) The silk fibroin fiber used in the present invention is safe, non-toxic, and has good biocompatibility and biodegradability;

[0027] (2) The present invention adopts a top-down method to prepare multi-scale silk fibroin fibers from silk fibers in natural silk cocoons, and electrostatically assembles them with silver nanowires to obtain silver nanowire-silk fibroin antibacterial nanofibers, which spontaneously form a spider web-like entanglement structure through steric hindrance and hydrogen bonding with glass fibers, thereby obtaining antibacterial air filter paper with high filtration performance and antibacterial properties.

[0028] (3) The preparation method of the present invention is simple and easy to operate, has low energy consumption, and is conducive to large-scale industrial production;

[0029] (4) The silver nanowire / silk fibroin fiber / glass fiber antibacterial air filter paper prepared by the present invention can effectively filter out 99% of PM2.5, bacteria and other air pollutants, and prevent secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Example 2 is an electron microscope image of silver nanowire / silk fibroin fiber / glass fiber.

[0031] Figure 2 It is a graph showing the antibacterial effects of glass fiber, silk fibroin / glass fiber obtained in Example 4, and silver nanowire / silk fibroin fiber / glass fiber on Escherichia coli.

[0032] Figure 3 It is a graph showing the antibacterial effects of glass fiber, silk fibroin / glass fiber obtained in Example 4, and silver nanowire / silk fibroin fiber / glass fiber on Staphylococcus aureus. DETAILED DESCRIPTION

[0033] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. If the manufacturer of the reagents or instruments used is not indicated, they are deemed to be conventional products that can be purchased commercially.

[0034] Example 1

[0035] A method for preparing a silver nanowire / silk fibroin fiber / glass fiber composite filter paper comprises the following steps:

[0036] (1) washing natural silkworm cocoons, chopping them into pieces of 1-2 cm, degumming for 0.5 h, and obtaining crude silk fibroin fibers; the obtained crude silk fibroin fibers were subjected to a solvent method, i.e., a ternary solution of water / anhydrous ethanol / calcium chloride with a molar ratio of 1:2:8 was prepared, 2 g of the degummed silk fibroin fibers were soaked in the ternary solution, and the fibers were swollen for 24 h, and then mechanically crushed for 10 min under alkaline conditions of pH 9.0, and dialyzed with deionized water to obtain 4 wt% multi-scale silk fibroin fibers;

[0037] (2) reducing 0.1 g of silver nitrate in a 1.6 g / L polypyrrolidone ethylene glycol solution in an oil bath at 130° C., washing the solution with acetone, and dispersing the solution in 10 mL of deionized water to obtain a 2 wt % silver nanowire solution;

[0038] (3) under stirring, adding the 2 wt % silver nanowire solution described in step 2 to the 50 mL of multi-scale silk fibroin fiber containing 4 wt % described in step 1, and obtaining multi-scale silver nanowire / silk fibroin fiber by electrostatic assembly;

[0039] (4) Dispersing 2.5 g of glass fiber in water to obtain a glass fiber aqueous dispersion, adding the multi-scale silver nanowire / silk fibroin fiber with a solid content of 0.3 g described in step 3 to the glass fiber aqueous dispersion, and stirring thoroughly to obtain a silver nanowire / silk fibroin fiber / glass fiber dispersion. The dispersion is subjected to a wet papermaking process to obtain a silver nanowire / silk fibroin fiber / glass fiber antibacterial air filter paper (drying temperature at 90-95° C.).

[0040] Example 2

[0041] A method for preparing a silver nanowire / silk fibroin fiber / glass fiber composite filter paper comprises the following steps:

[0042] (1) washing natural silkworm cocoons, chopping them, and degumming them for 0.5 h to obtain crude silk fibroin fibers, and treating the obtained crude silk fibroin fibers with a solvent method, i.e., preparing a ternary solution of water / anhydrous ethanol / calcium chloride with a molar ratio of 1:2:8, taking 2 g of the degummed silk fibroin fibers and soaking them in the ternary solution for swelling for 24 h, and then mechanically crushing them for 15 min under alkaline conditions of pH 9.0, and dialyzing them with deionized water to obtain 4 wt% multi-scale silk fibroin fibers;

[0043] (2) reducing 0.3 g of silver nitrate in a 3.2 g / L polypyrrolidone ethylene glycol solution in an oil bath at 130° C., washing the solution with acetone, and dispersing the solution in 10 mL of deionized water to obtain a 2 wt % silver nanowire solution;

[0044] (3) under stirring, adding the 2 wt % silver nanowire solution described in step 2 to the 50 mL of multi-scale silk fibroin fiber containing 4 wt % described in step 1, and obtaining multi-scale silver nanowire / silk fibroin fiber by electrostatic assembly;

[0045] (4) Dispersing 2.4 g of glass fiber in water to obtain a glass fiber aqueous dispersion, adding the multi-scale silver nanowire / silk fibroin fiber with a solid content of 0.4 g described in step 3 to the glass fiber aqueous dispersion, and stirring thoroughly to obtain a silver nanowire / silk fibroin fiber / glass fiber dispersion. The silver nanowire / silk fibroin fiber / glass fiber antibacterial air filter paper (drying temperature at 90-95° C.) is obtained by a wet papermaking process. Figure 1 As shown in the electron microscope of silver nanowires / silk fibroin fibers / glass fibers, an interwoven fiber network is formed between the silver nanowires / silk fibroin fibers and the glass fibers.

[0046] Example 3

[0047] A method for preparing a silver nanowire / silk fibroin fiber / glass fiber composite filter paper comprises the following steps:

[0048] (1) washing natural silkworm cocoons, chopping them, and degumming them for 0.5 h to obtain crude silk fibroin fibers, and treating the obtained crude silk fibroin fibers with a solvent method, i.e., preparing a ternary solution of water / anhydrous ethanol / calcium chloride with a molar ratio of 1:2:8, taking 2 g of the degummed silk fibroin fibers and soaking them in the ternary solution for swelling for 24 h, and then mechanically crushing them under alkaline conditions of pH 9 for 20 min, and dialyzing them with deionized water to obtain 6 wt% multi-scale silk fibroin fibers;

[0049] (2) reducing 0.5 g of silver nitrate in a 4.8 g / L polypyrrolidone ethylene glycol solution in an oil bath at 130° C., washing the solution with acetone, and dispersing the solution in 10 mL of deionized water to obtain a 3 wt % silver nanowire solution;

[0050] (3) under stirring, adding the 3 wt % silver nanowire solution described in step 2 to the 50 mL of multi-scale silk fibroin fiber containing 6 wt % described in step 1, and obtaining the multi-scale silver nanowire / silk fibroin fiber by electrostatic assembly;

[0051] (4) Dispersing 2.3 g of glass fiber in water to obtain a glass fiber aqueous dispersion, adding the multi-scale silver nanowire / silk fibroin fiber with a solid content of 0.5 g described in step 3 to the glass fiber aqueous dispersion, and stirring thoroughly to obtain a silver nanowire / silk fibroin fiber / glass fiber dispersion. The dispersion is subjected to a wet papermaking process to obtain a silver nanowire / silk fibroin fiber / glass fiber antibacterial air filter paper (drying temperature at 90-95° C.).

[0052] Example 4

[0053] A method for preparing a silver nanowire / silk fibroin fiber / glass fiber composite filter paper comprises the following steps:

[0054] (1) washing natural silkworm cocoons, chopping them, and degumming them for 0.5 h to obtain crude silk fibroin fibers, and treating the obtained crude silk fibroin fibers with a solvent method, i.e., preparing a ternary solution of water / anhydrous ethanol / calcium chloride with a molar ratio of 1:2:8, taking 2 g of the degummed silk fibroin fibers and soaking them in the ternary solution for swelling for 24 h, and then mechanically crushing them for 25 min under alkaline conditions of pH 9.0, and dialyzing them with deionized water to obtain 8 wt% multi-scale silk fibroin fibers;

[0055] (2) reducing 0.6 g of silver nitrate in a 6.4 g / L polypyrrolidone ethylene glycol solution in an oil bath at 130° C., washing the solution with acetone, and dispersing the solution in 10 mL of deionized water to obtain a 4 wt % silver nanowire solution;

[0056] (3) under stirring, adding the 4 wt % silver nanowire solution described in step 2 dropwise to the 50 mL of multi-scale silk fibroin fiber containing 8 wt % described in step 1 to obtain multi-scale silver nanowire / silk fibroin fiber by electrostatic assembly;

[0057] (4) Disperse 2.2 g of glass fiber in water to obtain a glass fiber aqueous dispersion, add the multi-scale silver nanowire / silk fibroin fiber with a solid content of 0.6 g described in step 3 to the glass fiber aqueous dispersion, and stir thoroughly to obtain a silver nanowire / silk fibroin fiber / glass fiber dispersion. The dispersion is subjected to a wet papermaking process to obtain a silver nanowire / silk fibroin fiber / glass fiber antibacterial air filter paper (drying temperature at 90-95°C). Figure 2 , Figure 3 The antibacterial effect of silver nanowire / silk fibroin fiber / glass fiber antibacterial air filter paper on Escherichia coli and Staphylococcus aureus is shown, indicating that the prepared antibacterial air filter paper has excellent antibacterial effect on Escherichia coli and Staphylococcus aureus.

[0058] Example 5

[0059] A method for preparing a silver nanowire / silk fibroin fiber / glass fiber composite filter paper comprises the following steps:

[0060] (1) washing natural silkworm cocoons, chopping them, and degumming them for 0.5 h to obtain crude silk fibroin fibers, and treating the obtained crude silk fibroin fibers with a solvent method, i.e., preparing a ternary solution of water / anhydrous ethanol / calcium chloride with a molar ratio of 1:2:8, taking 2 g of the degummed silk fibroin fibers and soaking them in the ternary solution for swelling for 24 h, and then mechanically crushing them for 30 min under alkaline conditions of pH 9, and dialyzing them with deionized water to obtain 10 wt% multi-scale silk fibroin fibers;

[0061] (2) reducing 0.7 g of silver nitrate in 8.0 g / L polypyrrolidone ethylene glycol solution in an oil bath at 130° C., washing the solution with acetone, and dispersing the solution in 10 mL of deionized water to obtain a 5 wt % silver nanowire solution;

[0062] (3) under stirring, adding the 5 wt % silver nanowire solution described in step 2 to the 50 mL of multi-scale silk fibroin fiber containing 10 wt % of the multi-scale silver nanowire / silk fibroin fiber described in step 1 to obtain the multi-scale silver nanowire / silk fibroin fiber by electrostatic assembly;

[0063] (4) Dispersing 2.1 g of glass fiber in water to obtain a glass fiber aqueous dispersion, adding the multi-scale silver nanowire / silk fibroin fiber with a solid content of 0.7 g described in step 3 to the glass fiber aqueous dispersion, and stirring to obtain a silver nanowire / silk fibroin fiber / glass fiber dispersion. The dispersion is subjected to a wet papermaking process to obtain a silver nanowire / silk fibroin fiber / glass fiber antibacterial air filter paper (drying temperature at 90-95° C.).

[0064] The above embodiments are only preferred implementation modes of the present invention and are only used to explain the present invention rather than to limit the present invention. Any changes, substitutions, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for preparing a silver nanowire / silk fibroin fiber / glass fiber composite filter paper, characterized in that: The steps include: (1) washing, chopping and degumming natural silk cocoons to obtain crude silk fibroin fibers, swelling the obtained crude silk fibroin fibers by a solvent method, then crushing them under alkaline conditions, and dialyzing them with deionized water to obtain multi-scale silk fibroin fibers; (2) in a high temperature oil bath, using polypyrrolidone and ethylene glycol as a template and a reducing agent to reduce silver nitrate, and then fully washing with acetone and dispersing in deionized water to obtain a silver nanowire solution; (3) under stirring, adding the silver nanowire solution obtained in step (2) to the multi-scale silk fibroin fiber dispersion obtained in step (1) to obtain a multi-scale silver nanowire / silk fibroin fiber dispersion by electrostatic assembly; (4) dispersing glass fibers in an acidic aqueous solution to obtain a glass fiber aqueous dispersion, adding the multi-scale silver nanowire / silk fibroin fiber dispersion obtained in step (3) to the glass fiber aqueous dispersion, stirring thoroughly to obtain a silver nanowire / silk fibroin fiber / glass fiber dispersion, and subjecting the silver nanowire / silk fibroin fiber / glass fiber dispersion to a wet papermaking process to obtain a silver nanowire / silk fibroin fiber / glass fiber composite filter paper.

2. The method for preparing the silver nanowire / silk fibroin fiber / glass fiber composite filter paper according to claim 1, characterized in that: In step (1), the cocoons are chopped into pieces of 1-2 cm, the mass percentage concentration of sodium bicarbonate used for degumming is 1%-2%, and the degumming time is 30min-60min.

3. The method for preparing the silver nanowire / silk fibroin fiber / glass fiber composite filter paper according to claim 1, characterized in that: In step (1), the scale of the multi-scale silk fibroin fiber is 100nm-2μm; the alkaline condition is 1%-5% sodium hydroxide solution; and the mechanical crushing time is 5min-30min.

4. The method for preparing the silver nanowire / silk fibroin fiber / glass fiber composite filter paper according to claim 1, characterized in that: In step (1), the solvent method is specifically as follows: preparing a ternary solution of water / anhydrous ethanol / calcium chloride with a molar ratio of 1:2:8 to 1:4:8, taking 2g to 4g of degummed silk fibroin fibers and soaking them in the ternary solution for swelling for 24-48 hours.

5. The method for preparing the silver nanowire / silk fibroin fiber / glass fiber composite filter paper according to claim 1, characterized in that: In step (2), the mass percentage concentration of the silver nanowires is 1%-2%; the specific conditions of the high-temperature oil bath are: 130-150°C; the concentration of the polypyrrolidone in ethylene glycol is 1.0-8.0 g / L, and the concentration of silver nitrate in ethylene glycol is 5.0-10.0 g / L.

6. The method for preparing the silver nanowire / silk fibroin fiber / glass fiber composite filter paper according to claim 1, characterized in that: In step (3), the amount of the silver nanowire solution added to the multi-scale silk fibroin fiber is 5-10 ml, and the amount of the multi-scale silk fibroin fiber dispersion added is 50 mL-100 mL.

7. The method for preparing the silver nanowire / silk fibroin fiber / glass fiber composite filter paper according to claim 1, characterized in that: In step (4), the mass percentage concentration of the silver nanowires / silk fibroin fibers is between 10% and 20%.

8. The method for preparing the silver nanowire / silk fibroin fiber / glass fiber composite filter paper according to claim 1, characterized in that: In step (4), the acidic aqueous solution is a 10%-20% sulfuric acid aqueous solution; the mass percentage concentration of the glass fiber aqueous dispersion is 0.05%-0.10%; the added amounts of the multi-scale silver nanowires / silk fibroin fibers and the glass fiber aqueous dispersion satisfy: the mass ratio of the multi-scale silver nanowires / silk fibroin fibers to the glass fiber aqueous dispersion is 10%-20%; the drying temperature of the wet drying process is 90°C-95°C.

9. The silver nanowire / silk fibroin fiber / glass fiber composite filter paper prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The filter paper can effectively filter out 99% of PM2.5 and bacterial air pollutants, and can kill bacteria, preventing bacteria from multiplying on the filter paper and causing secondary pollution.

10. The silver nanowire / silk fibroin fiber / glass fiber composite filter paper according to claim 9 is used for air filtration.

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