High-flux filter paper for water filtration and preparation method thereof

Abstract

The invention discloses high-flux filter paper for water filtration and a preparation method thereof. The method comprises the following steps: by taking natural silkworm cocoons as a silk fibroin fiber raw material, preparing silk fibroin fibers through a synergistic effect of solvent dissolution and mechanical stripping; the silk fibroin fibers and the polyester long and short fibers form an interwoven network structure through a physical entanglement and electrostatic assembly technology; the silk fibroin fiber / polyester long fiber / polyester short fiber high-flux water filtering filter paper is prepared from polyester long and short fibers serving as a filtering framework and silk fibroin fibers through a wet papermaking process. The silk fibroin fiber / polyester long fiber / polyester short fiber high-flux water filtration filter paper obtained by the invention has high flux and high toughness through bionic cobweb multistage structural design, effectively filters water pollutants such as fine particulate matters and micro-nano plastic particulate matters, and is suitable for high-precision filtration in severe environments such as a cooling water system and radioactive wastewater treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of water filtration, and in particular to a filter paper for high-throughput water filtration and a preparation method thereof. Background Art

[0002] Polyester long-fiber filter media is widely used in water filtration facilities. This is primarily due to the stringent water quality requirements imposed by these facilities, making the use of efficient and durable filter materials crucial. Polyester long-fiber's key advantages include high strength, high modulus, and high heat resistance. These properties enable long-term, stable operation in industrial environments, effectively filtering water pollutants such as fine particulate matter and microplastic particles. Furthermore, the high strength and wear resistance of polyester long-fiber ensure a long filter life, which is crucial for reducing maintenance costs and improving filtration efficiency. Compared to glass fiber in water filtration, polyester long-fiber does not undergo silica precipitation during filtration, which can introduce impurities. Furthermore, traditional polyester long-fiber filter media captures particles and other water pollutants from contaminated water through its complex interwoven fiber layers, but this suffers from low filtration efficiency. Currently, conventional approaches to improve filtration efficiency are to increase the density of polyester long-fiber, but this typically results in a decrease in water flux, resulting in reduced wastewater treatment capacity. Therefore, if the microstructure of polyester long fiber filter paper can be controlled to achieve both good filtration efficiency and high water flux, it is the technical key to the current water filtration filter paper.

[0003] Silk fibroin, the fundamental component of natural silk fibers, is composed of multiple amino acids, such as glycine, alanine, and serine. Its molecular structure exhibits a β-folded structure, which provides it with excellent strength and toughness. Furthermore, silk fibroin fibers are composed of proteins linked by amide bonds, resulting in a large number of hydrophilic groups on their surfaces, such as polar amino acid residues, hydroxyl groups, carboxyl groups, and amide groups. These groups can form numerous hydrogen bonds with water molecules. Furthermore, the naturally porous surface of silk fibroin fibers facilitates water absorption and transport. Previous studies (Small, 2025, 21, 2500226) have reported an environmentally friendly filter material based on silk fibroin nanofiber aerogel, which exhibits excellent biodegradability and filtration capacity for a wide range of pollutants. However, this material suffers from poor structural stability in water, requiring the addition of chitosan to reinforce its structure. Furthermore, there is a trade-off between filtration efficiency and flux, making it difficult to achieve both high efficiency and high flux. However, its high preparation cost and limited pore size control restrict its application in complex aqueous environments. By utilizing the spontaneous entanglement between silk fibroin fibers and polyester long fibers due to steric hindrance and hydrogen bonding to regulate the micro-nanopore structure in polyester long fiber water filtration materials, it is expected to improve its folding resistance and wear resistance, extend the life of the filter material, and achieve high filtration efficiency and high water flux, and prepare high-flux filter paper for water filtration. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention aims to provide a high-throughput water filtration filter paper and a preparation method thereof.

[0005] The purpose of the present invention is to address the deficiencies of the prior art and provide a high-throughput water filtration filter paper, specifically a water filtration filter paper with high filtration efficiency and high water flux.

[0006] The present invention also aims to provide a method for preparing the aforementioned high-throughput water filtration filter paper. The method comprises preparing silk fibers from natural silkworm cocoons into fibroin fibers, which are then electrostatically assembled with polyester filaments to produce a fibroin fiber / polyester filament / polyester staple fiber composite filter paper. The fibroin fibers, the polyester filaments, and the polyester staple fibers spontaneously entangle through steric hindrance and hydrogen bonding, resulting in a water filtration filter paper with high filtration efficiency and high water flux.

[0007] The present invention also aims to provide the use of the above filter paper with high filtration performance and high water flux in water filtration.

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

[0009] The invention provides a filter paper for high-throughput water filtration, in particular a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper.

[0010] The present invention provides a method for preparing the above-mentioned silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper, comprising the following steps:

[0011] (1) Pre-treating natural silkworm cocoons to obtain crude silk fibroin fibers, then subjecting the fibers to solvent swelling to relax the fiber structure, mechanically shearing the fibers, and dialysis with deionized water to purify the fibers, thereby obtaining silk fibroin fibers;

[0012] (2) Pre-treating the polyester long fiber and polyester short fiber: first, soaking the polyester long fiber in deionized water and then deflocculanting it with a deflocculant; then, adding the polyester short fiber and deflocculanting it again with a deflocculant to obtain a uniformly dispersed polyester long fiber / polyester short fiber dispersion;

[0013] (3) adding the polyester long fiber / polyester short fiber dispersion of step (2) to the silk fibroin fiber of step (1) under stirring to obtain a silk fibroin fiber / polyester long fiber / polyester short fiber dispersion by electrostatic assembly;

[0014] (4) The silk fibroin fiber / polyester long fiber / polyester short fiber dispersion prepared in step (3) is fully stirred and subjected to a wet papermaking process to obtain a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper.

[0015] Preferably, in step (1), the pretreatment of the natural silk cocoons includes washing and degumming steps, wherein deionized water is used for washing, and a sodium bicarbonate solution with a concentration of 0.5%-2% is used for degumming. The degumming time is 30-60 minutes, and the size of the shredded silk cocoon fragments is 0.3-0.5 cm.

[0016] Preferably, in step (1), the solvent is a ternary solvent, wherein the molar ratio of calcium chloride: anhydrous ethanol: water is 1: 1.5-2.5: 6-10.

[0017] Preferably, in step (1), the size of the silk fibroin fibers is 200 nm-2 μm; and the mechanical crushing time is 60-180 min.

[0018] Preferably, the mass fraction of the silk fibroin fiber in step (1) is 10%-20%.

[0019] Preferably, in step (2), the molecular weight of the polyester long fiber is between 20,000 and 30,000, the size is between 1 and 3 mm, and the concentration is 1.0-8.0 g / L; the molecular weight of the polyester short fiber is between 15,000 and 25,000, the size is between 0.1 and 0.5 mm, and the concentration is 1.0-8.0 g / L.

[0020] Preferably, in the polyester long fiber / polyester short fiber dispersion liquid described in step (2), the polyester short fibers account for 40%-50%; and the polyester long fibers account for 30%-40%.

[0021] Preferably, in step (2), the stirring speed of the deflaking machine is 5000-25000 rpm, and the deflaking time is 15 min-30 min.

[0022] Furthermore, in step (3), the mass ratio of the added polyester long fiber / polyester short fiber dispersion is 80%-90%; and the concentration of the silk fibroin fiber is 10%-20%.

[0023] Furthermore, in step (3), the stirring time is 10 min-20 min.

[0024] Furthermore, in step (4), the wet papermaking process conditions are: drying temperature 85-95° C., and drying time 10-30 min.

[0025] The present invention provides a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper prepared by the above-mentioned preparation method, which has a hierarchical fiber network structure (a spider web-like multi-level structure) with a pore size of 1-1.5 μm. The three-dimensional interlaced fiber network formed by the silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper can effectively filter out more than 90% of water pollutants such as tiny particles and microplastics with a size of 1-5 mm, and has a water flux of more than 1000 L·m -2 ·h -1 bar -1 .

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

[0027] (1) Using natural silkworm cocoons as the raw material of silk fibroin fibers, silk fibroin fibers were prepared by the synergistic effect of solvent dissolution and mechanical stripping; the silk fibroin fibers and polyester long and short fibers were formed into an interwoven network structure through physical entanglement and electrostatic assembly technology; the polyester long and short fibers were used as the filter skeleton and the silk fibroin fibers were prepared through a wet papermaking process to prepare silk fibroin fiber / polyester long fiber / polyester short fiber high-throughput water filtration filter paper.

[0028] (2) The silk fibroin fiber / polyester long fiber / polyester short fiber high-throughput water filtration filter paper obtained by the present invention has a bionic spider web multi-level structure design, which has both high throughput and high toughness, and can effectively filter water pollutants such as fine particles and micro-nano plastic particles. It is suitable for high-precision filtration in harsh environments such as cooling water systems and radioactive wastewater treatment.

[0029] (3) The silk fibroin used in the present invention is derived from natural silk, is safe and green, and has good biocompatibility and biodegradability.

[0030] (4) 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.

[0031] (5) The silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper obtained by the method of the present invention can effectively filter out more than 90% of water pollutants such as tiny particles and microplastics with a size of 1-5 mm, and the water flux is greater than 1000 L·m -2 ·h -1 bar -1 . BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is an electron microscope image of the silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper prepared in Example 2.

[0033] Figure 2 This is a diagram of the filtration efficiency of the silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper prepared in Example 3.

[0034] Figure 3 This is a comparison chart of the water flux of the composite filter paper prepared in Example 3 and silk fibroin fiber, polyester long fiber, and polyester short fiber. DETAILED DESCRIPTION

[0035] The specific implementation of the present invention is further described below with reference to 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 any processes not specifically described 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.

[0036] Example 1

[0037] A method for preparing a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper for high-throughput water filtration comprises the following steps:

[0038] (1) Washing natural silk cocoons, degumming for 0.5 h, degumming twice to obtain crude silk fibroin fibers, adding 2 g of crude silk fibroin fibers to 500 mL of a ternary solution (calcium chloride: anhydrous ethanol: water molar ratio of 1:2:10), soaking at room temperature for 2 days, then taking out, and then mechanically crushing for 90 min, dialyzing with deionized water and concentrating, adjusting the final mass fraction of silk fibroin fibers to 10%, and obtaining a silk fibroin fiber dispersion;

[0039] (2) Add 1.25 g of polyester long fiber and 1.00 g of polyester short fiber into deionized water with a polyester long fiber concentration of 6% and a polyester short fiber concentration of 6%. After mixing evenly, stir vigorously for 5 minutes to obtain a uniformly dispersed polyester long fiber / polyester short fiber dispersion.

[0040] (3) Under stirring conditions, 50 mL of 10 wt% silk fibroin fiber from step (1) was added to the polyester long fiber / polyester short fiber dispersion from step (2), and after sufficient stirring for 15 minutes, a silk fibroin fiber / polyester long fiber / polyester short fiber dispersion was obtained by electrostatic assembly;

[0041] (4) The silk fibroin fiber / polyester long fiber / polyester short fiber dispersion obtained in step (3) is used to prepare filter paper through a wet papermaking process. The specific process flow is as follows: 7 L of water and the dispersion are added to a forming barrel, and after sufficient dispersion, vacuum filtration and dehydration are performed; during this period, the filter paper is formed in the filter screen and then placed on a drying table for heating (drying temperature is 85-95°C, drying time is 10 minutes), thereby obtaining a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper for high-throughput water filtration.

[0042] Example 2

[0043] A method for preparing a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper for high-throughput water filtration comprises the following steps:

[0044] (1) Washing natural silk cocoons, degumming for 0.5 h, degumming twice to obtain crude silk fibroin fibers, adding 2 g of crude silk fibroin fibers to 500 mL of a ternary solution (calcium chloride: anhydrous ethanol: water molar ratio of 1:2:9), soaking at room temperature for 2 days, then taking out, and then mechanically crushing for 90 min, dialyzing with deionized water, and adjusting the final mass fraction of silk fibroin fibers to 12.5%, to obtain a silk fibroin fiber dispersion;

[0045] (2) 1.19 g of polyester long fiber and 0.93 g of polyester short fiber were added to deionized water with a polyester long fiber concentration of 7% and a polyester short fiber concentration of 7%. After mixing evenly, the mixture was vigorously stirred for 10 minutes to obtain a uniformly dispersed polyester long fiber / polyester short fiber dispersion.

[0046] (3) Under stirring conditions, 50 mL of the 12.5 wt% silk fibroin fiber prepared in step (1) was added to the polyester long fiber / polyester short fiber dispersion prepared in step (2), and after sufficient stirring for 15 minutes, a silk fibroin fiber / polyester long fiber / polyester short fiber dispersion was obtained by electrostatic assembly;

[0047] (4) The silk fibroin fiber / polyester long fiber / polyester short fiber dispersion obtained in step (3) is used to prepare filter paper through a wet papermaking process. The specific process flow is as follows: 7 L of water and the dispersion are added to a forming barrel, and after sufficient dispersion, vacuum filtration and dehydration are performed; during this period, the filter paper is formed in the filter screen and then placed on a drying table for heating (drying temperature is 85-95°C, drying time is 15 minutes), thereby obtaining a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper for high-throughput water filtration.

[0048] Figure 1 This electron micrograph of the silk fibroin fiber / polyester long fiber / polyester short fiber filter paper prepared in Example 2 shows a three-dimensional random network structure formed by the polyester long fibers, polyester short fibers, and silk fibroin fibers. The image shows the interweaving of fibers of varying thicknesses, with the coarser polyester fibers forming a supporting framework and the finer silk fibroin fibers uniformly filling the pores, creating a microscopic porous structure.

[0049] Example 3

[0050] A method for preparing a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper for high-throughput water filtration comprises the following steps:

[0051] (1) Washing natural silk cocoons, degumming for 0.5 h, degumming twice to obtain crude silk fibroin fibers, adding 2 g of crude silk fibroin fibers to 500 mL of a ternary solution (calcium chloride: anhydrous ethanol: water molar ratio of 1:2:8), soaking at room temperature for 2 days, then taking out, and then mechanically crushing for 120 min, dialyzing and concentrating with deionized water, and adjusting the final mass fraction of silk fibroin fibers to 15% to obtain a silk fibroin fiber dispersion;

[0052] (2) 1.12 g of polyester long fiber and 0.88 g of polyester short fiber were added to deionized water with a polyester long fiber concentration of 8% and a polyester short fiber concentration of 8%. After mixing evenly, the mixture was vigorously stirred for 15 min to obtain a uniformly dispersed polyester long fiber / polyester short fiber dispersion.

[0053] (3) adding 50 mL of 15 wt% silk fibroin fiber from step (1) to the polyester long fiber / polyester short fiber dispersion from step (2), stirring thoroughly for 15 minutes, and then electrostatically assembling to obtain a silk fibroin fiber / polyester long fiber / polyester short fiber dispersion;

[0054] (4) The silk fibroin fiber / polyester long fiber / polyester short fiber dispersion obtained in step (3) is used to prepare filter paper through a wet papermaking process. The specific process flow is as follows: 7 L of water and the dispersion are added to a forming barrel, and after sufficient dispersion, vacuum filtration and dehydration are performed; during this period, the filter paper is formed in the filter screen and then placed on a drying table for heating (drying temperature is 85-95°C, drying time is 20 minutes), thereby obtaining a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper for high-throughput water filtration.

[0055] Example 4

[0056] A method for preparing a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper for high-throughput water filtration comprises the following steps:

[0057] (1) Washing natural silk cocoons, degumming for 0.5 h, degumming twice to obtain crude silk fibroin fibers, adding 2 g of crude silk fibroin fibers to 500 mL of a ternary solution (calcium chloride: anhydrous ethanol: water molar ratio of 1:2.5:7), soaking at room temperature for 2 days, then taking out, and then mechanically crushing for 150 min, dialyzing and concentrating with deionized water, and adjusting the final mass fraction of silk fibroin fibers to 17.5% to obtain a silk fibroin fiber dispersion;

[0058] (2) 1.06 g of polyester long fiber and 0.82 g of polyester short fiber were added to deionized water with a polyester long fiber concentration of 9% and a polyester short fiber concentration of 9%. After mixing evenly, the mixture was vigorously stirred for 15 minutes to obtain a uniformly dispersed polyester long fiber / polyester short fiber dispersion.

[0059] (3) adding 50 mL of the 17.5 wt% silk fibroin fiber prepared in step (1) to the polyester filament / polyester staple fiber dispersion prepared in step (2), stirring the mixture for 15 min, and then electrostatically assembling the mixture to obtain a silk fibroin fiber / polyester filament / polyester staple fiber dispersion;

[0060] (4) The silk fibroin fiber / polyester long fiber / polyester short fiber dispersion obtained in step (3) is used to prepare filter paper through a wet papermaking process. The specific process flow is as follows: 7 L of water and the dispersion are added to a forming barrel, and after sufficient dispersion, vacuum filtration and dehydration are performed; during this period, the filter paper is formed in the filter screen and then placed on a drying table for heating (drying temperature is 85-95°C, drying time is 25 minutes), thereby obtaining a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper for high-throughput water filtration.

[0061] Example 5

[0062] A method for preparing a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper for high-throughput water filtration comprises the following steps:

[0063] (1) Washing natural silk cocoons, degumming for 0.5 h, degumming twice to obtain crude silk fibroin fibers, adding 2 g of crude silk fibroin fibers to 500 mL of a ternary solution (calcium chloride: anhydrous ethanol: water molar ratio of 1:1.5:6), soaking at room temperature for 2 days, then taking out, and then mechanically crushing for 150 min, dialyzing and concentrating with deionized water, and adjusting the final mass fraction of silk fibroin fibers to 20% to obtain a silk fibroin fiber dispersion;

[0064] (2) 1.00 g of polyester long fiber and 0.75 g of polyester short fiber were added to deionized water with a polyester long fiber concentration of 10% and a polyester short fiber concentration of 10%. After mixing evenly, the mixture was vigorously stirred for 20 minutes to obtain a uniformly dispersed polyester long fiber / polyester short fiber dispersion.

[0065] (3) adding 50 mL of 20 wt% silk fibroin fiber from step (1) to the polyester long fiber / polyester short fiber dispersion from step (2), stirring thoroughly for 15 minutes, and then electrostatically assembling to obtain a silk fibroin fiber / polyester long fiber / polyester short fiber dispersion;

[0066] (4) The silk fibroin fiber / polyester long fiber / polyester short fiber dispersion obtained in step (3) is used to prepare filter paper through a wet papermaking process. The specific process flow is as follows: 7 L of water and the dispersion are added to a forming barrel, and after sufficient dispersion, vacuum filtration and dehydration are performed; during this period, the filter paper is formed in the filter screen and then placed on a drying table for heating (drying temperature is 85-95°C, drying time is 30 minutes), thereby obtaining a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper for high-throughput water filtration.

[0067] The filtration efficiency performance test of the silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper prepared in the embodiment was carried out. The test method adopted was to test the number of polystyrene microspheres of different sizes before and after filtration using a liquid laser particle counter to obtain the filtration efficiency of the composite filter paper.

[0068] Figure 2 This is a graph showing the filtration efficiency of the silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper prepared in Example 3. It shows that the composite filter paper exhibits high filtration efficiency for particles of varying water diameters. For particles larger than 300 nm, the filtration efficiency remains between approximately 95% and 98%, demonstrating that the silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper exhibits excellent particle retention and is suitable for use in water purification and other fields.

[0069] Figure 3 The water flux diagram of silk fibroin fiber, polyester long fiber, polyester short fiber and composite filter paper prepared in Example 3 is shown. It can be seen that there are significant differences in the flux of different component materials. Among them, the water flux of polyester short fiber is the highest, reaching 1450 L·m -2 ·h -1 bar -1 , while the water flux of silk fibroin fiber is relatively low, only 720 L·m -2 ·h -1 bar -1 Polyester long fiber has a large diameter and strong support, and its water flux is 1100L·m -2 ·h -1 bar -1 The water flux of the composite filter paper constructed by the three fibers reached 1250 L·m -2 ·h -1 bar -1 , taking into account both flux and structural stability, and significantly better than the filtration performance of single silk protein fiber. This shows that the synergistic construction of silk fibroin fiber and polyester long and short fibers can improve the mechanical strength and stability of filter paper while maintaining high water flux, effectively overcoming the trade-off between filtration efficiency and flux in traditional filter materials.

[0070] 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 filter paper for high-throughput water filtration, characterized in that: The filter paper is a composite filter paper of silk fibroin fiber / polyester long fiber / polyester short fiber, and the preparation method comprises the following steps: (1) Pre-treating natural silk cocoons to obtain crude silk fibroin fibers, using a solvent to perform swelling treatment to relax the fiber structure, chopping, and dialysis purification to obtain silk fibroin fibers; (2) Pre-treating the polyester long fiber and the polyester short fiber: first, soaking the polyester long fiber in deionized water to loosen it; then adding the polyester short fiber and loosening it again to obtain a uniformly dispersed polyester long fiber / polyester short fiber dispersion; (3) adding the polyester long fiber / polyester short fiber dispersion of step (2) to the silk fibroin fiber of step (1) under stirring to obtain a silk fibroin fiber / polyester long fiber / polyester short fiber dispersion by electrostatic assembly; (4) The silk fibroin fiber / polyester long fiber / polyester short fiber dispersion prepared in step (3) is fully stirred and subjected to a wet papermaking process to obtain a silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper.

2. The preparation method according to claim 1, characterized in that In step (1), the natural silk cocoons are pretreated including washing and degumming steps, wherein deionized water is used for washing and a sodium bicarbonate solution with a concentration of 0.5% to 2% is used for degumming. The degumming time is 30 to 60 minutes, and the size of the shredded silk cocoon fragments is about 0.3 to 0.5 cm.

3. The preparation method according to claim 1, characterized in that In step (1), the solvent is a ternary solvent, wherein the molar ratio of calcium chloride: anhydrous ethanol: water is 1: 1.5-2.5: 6-10; the size of the silk fibroin fiber is 200nm-2μm; and the mechanical crushing time is 60-180min.

4. The preparation method according to claim 1, characterized in that In step (2), the molecular weight of the polyester long fiber is between 20,000 and 30,000, the size is between 1 and 3 mm, and the concentration is 1.0-8.0 g / L; the molecular weight of the polyester short fiber is between 15,000 and 25,000, the size is between 0.1 and 0.5 mm, and the concentration is 1.0-8.0 g / L.

5. The preparation method according to claim 1, characterized in that In the polyester long fiber / polyester short fiber dispersion described in step (2), the polyester short fiber accounts for 40%-50%; and the polyester long fiber accounts for 30%-40%.

6. The preparation method according to claim 1, characterized in that In step (2), the stirring speed of the decomposition is 5000-25000 rpm, and the decomposition time is 15-30 min.

7. The preparation method according to claim 1, characterized in that In step (3), the mass ratio of the added polyester long fiber / polyester short fiber dispersion is 80%-90%; the concentration of the silk fibroin fiber is 10%-20%.

8. The preparation method according to claim 1, characterized in that In step (4), the wet papermaking process conditions are: drying temperature 85-95° C., and drying time 10-30 min.

9. The silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper obtained by the preparation method according to any one of claims 1 to 8, characterized in that: It has a hierarchical fiber network structure with a pore size of 1-1.5μm.

10. Use of the silk fibroin fiber / polyester long fiber / polyester short fiber composite filter paper according to claim 9 in a water filtration system, characterized in that: It can filter out more than 90% of tiny pollutants with a size of 1-5mm, and the water flux is greater than 1000L·m -2 ·h -1 bar -1 .

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