An ultra-high efficiency and low resistance nanofiber air purification filter paper and a preparation method thereof

Abstract

The application discloses an ultra-high-efficiency and low-resistance nanofiber air purification filter paper and a preparation method thereof. The filter paper is composed of a three-dimensional network structure of spiral polyvinylidene fluoride nanofibers, and modified nanosilica is in-situ compounded in the fibers. In the preparation of the filter paper, the modified nanosilica and polyvinylidene fluoride are blended in an organic solvent, and a composite spinning solution is obtained through stirring and ultrasonic treatment; in the electrospinning, a receiving plate with periodic vibration is adopted to collect the fibers, spiral coiling of the induced jet flow is induced before solidification, and spiral nanofibers are formed; finally, the product is obtained through drying and hot-pressing shaping. The filter paper utilizes the elastic buffering of the spiral structure to reduce the airflow resistance and prolong the particle capture path, meanwhile, the modified particles are uniformly dispersed in the fibers, the fiber rigidity is enhanced, and the pore blockage is avoided, and the ultra-high-efficiency filtration and the low resistance are realized in cooperation.

Description

Technical Field

[0001] This invention relates to the fields of materials science and engineering, and in particular to an ultra-high efficiency, low resistance nanofiber air purification filter paper and its preparation method. Background Technology

[0002] With the increasing severity of air pollution, the demand for high-efficiency, low-resistance air purification filter paper is urgent. Electrospun nanofiber filter paper, due to its high porosity and fine structure, has shown excellent potential and become a research hotspot. Currently, most mainstream nanofiber filter papers are composed of straight or disordered fibers with a diameter greater than 60 nm. Although they have a certain filtration efficiency, the simple fiber structure and dense packing often lead to high airflow resistance, and it is difficult to achieve breakthroughs in capturing ultrafine particles (such as PM0.1). To improve performance, researchers have attempted to introduce rigid nanoparticles (such as silica and boron nitride) to enhance the mechanical properties of the fibers, but this usually comes at the cost of sacrificing porosity and has limited contribution to reducing resistance. In recent years, helical nanofiber structures have attracted much attention. Their unique three-dimensional coiled morphology can extend the particle capture path while maintaining high porosity and utilize elastic deformation to buffer airflow, making it an ideal configuration for achieving high efficiency and low resistance.

[0003] However, achieving stable and controllable fabrication of smaller diameter helical nanofibers remains a challenge in existing technologies, particularly in how to synergistically enhance rigidity with the helical structure to further improve the filter paper's stiffness, structural stability, and long-term performance. Therefore, developing a novel filter paper with smaller fiber diameters (<60 nm), a helical structure, and composite rigid nanoparticles is of significant scientific and practical value for overcoming the current bottleneck in balancing efficiency and resistance in filter materials. Summary of the Invention

[0004] To address the aforementioned issues, this invention proposes an ultra-efficient, low-resistance nanofiber air purification filter paper and its preparation method. The method involves inducing electrospinning jets through periodic vibration of a receiving plate to form helical nanofibers, while simultaneously in-situ composite of nano-silica modified with a silane coupling agent into the interior of polyvinylidene fluoride fibers to construct a three-dimensional elastic network with high porosity.

[0005] This invention can be achieved through the following technical solutions: A method for preparing an ultra-high efficiency, low resistance nanofiber air purification filter paper includes the following steps: Step 1: Mix polyvinylidene fluoride with nano-silica modified with silane coupling agent in an organic solvent. After stirring and ultrasonic treatment, the modified nano-silica is uniformly dispersed and in situ composited in the polyvinylidene fluoride body to obtain a composite spinning solution. Step 2: Inject the composite spinning solution into the injection pump for electrospinning. Use a receiving plate with periodic vibration to collect the fibers. The periodic vibration of the receiving plate induces the jet to spiral coil before solidification, forming helical nanofibers with a diameter of 30-60 nm and a helix diameter ratio of (10-30):1, which constitute a three-dimensional fiber network. The frequency of the periodic vibration is 5-50 Hz. Step 3: Dry the spiral nanofibers and hot-press them at 140-160℃ and 0.5-5MPa for 100-300s to form a stable cross-linked network between the fibers, thus obtaining nanofiber air purification filter paper. The spiral nanofibers and the modified nano-silica in situ composite inside the fibers work synergistically to maintain high porosity while extending the particle capture path by utilizing the elastic buffer of the spiral structure, and improving the fiber stiffness with the help of modified nano-silica, thereby achieving a balance between ultra-high efficiency filtration and low resistance and high structural stability.

[0006] Preferably, in step 1, the amount of nano-silica modified with silane coupling agent is 5%-40% of the mass of polyvinylidene fluoride, and the particle size is 10-100 nm.

[0007] Preferably, the stirring conditions in step 1 are 20-60℃ and 200-800 rpm for 6-24 hours; the ultrasonic treatment power is 200-800W and the duration is 30-120 minutes.

[0008] Preferably, the organic solvent in step 1 is N,N-dimethylformamide or tetrahydrofuran.

[0009] Preferably, in step 2, electrospinning is carried out in an environment with a relative humidity of 40%-65%, a spinning voltage of 15-35kV, a feeding rate of 0.5-3mL / h, and a receiving distance of 10-25cm.

[0010] The beneficial effects of this invention are: This invention achieves a strong interfacial bond between nanoparticles and the fiber matrix by uniformly dispersing and in-situ composited modified nano-silica into a polyvinylidene fluoride matrix. This enhances the intrinsic stiffness of the fiber while preventing pore blockage caused by particle agglomeration, ensuring a smooth fiber surface and complete preservation of interfiber pores. Simultaneously, a receiving plate subjected to periodic vibration is used to collect the fibers. The periodic vibration of the receiving plate induces the jet to spirally coil before solidification, stabilizing and forming helical nanofibers, thus constructing a high-porosity three-dimensional elastic network. The helical structure and the modified particles produce a significant synergistic effect: vibration induces the formation of a helical structure, which reduces airflow resistance through elastic buffering and improves particle capture efficiency through path extension, achieving high efficiency and low resistance; the in-situ composite of modified particles enhances fiber stiffness without sacrificing porosity, and the two work synergistically to achieve a breakthrough in ultra-high efficiency and low resistance performance.

[0011] Compared with Comparative Example 1, which uses a static receiving plate, the present invention reduces the pressure drop by 43.5% (from 62 Pa to 35 Pa) and increases the air permeability by 84.4% (from 12.2 mm / s to 22.5 mm / s) and the quality factor by 52.7% through the vibration-induced spiral structure. Compared with Comparative Example 2, which uses unmodified nanoparticles, the present invention increases the flexural strength by 59.2% (from 9.8 MPa to 15.6 MPa) and the elastic recovery rate by 7.9% (from 85.7% to 92.5%) through the uniform dispersion of modified particles, while reducing the pressure drop by 34.0%, fully demonstrating the indispensability of the synergistic effect of the spiral structure and modified particles. The air purification filter paper produced by this invention has a filtration efficiency of up to 99.9994% for PM0.3 particles, an initial pressure drop of 35-48 Pa, a quality factor as high as 0.119 Pa-1, a bending strength of 15.6-35.5 MPa, an elastic recovery rate of 92.5%-96.4%, and an air permeability of 19.7-28.6 mm / s, truly achieving a unity of ultra-high efficiency filtration, ultra-low resistance, high structural stability, and excellent air permeability. Attached Figure Description

[0012] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 The filtration performance of air purification filter paper; Figure 2 Mechanical properties of air purification filter paper; Figure 3 For the air permeability of air purification filter paper; Figure 4 This is a scanning electron microscope image of nanofiber air purification filter paper. Detailed Implementation

[0013] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0014] Example 1: A method for preparing an ultra-high efficiency, low resistance nanofiber air purification filter paper, comprising the following steps: Step 1: Disperse 5g of fumed silica nanoparticles in 200mL of anhydrous ethanol and sonicate for 30min. Under mechanical stirring, slowly add 0.5g of KH-550 to the dispersion and react in a 60℃ water bath for 6h. After the reaction is complete, collect the modified silica nanoparticles by centrifugation, wash them three times with ethanol, and dry them in a vacuum drying oven at 80℃ for 12h to obtain nano-silica modified with silane coupling agent. Step 2: Mix 2g of polyvinylidene fluoride, 0.1g of the above-mentioned modified nano-silica with a particle size of 10nm and 18g of N,N-dimethylformamide, stir at 200rpm for 24h at 20℃, and then treat with ultrasonic power of 200W for 120min to make the modified nano-silica uniformly dispersed and in-situ composite in the polyvinylidene fluoride body to obtain the composite spinning solution; Step 3: Inject the composite spinning solution into a 10mL syringe, install a 21G stainless steel flat-tipped needle as the spinning nozzle, fix the syringe on the feed pump, set the feed speed to 0.5mL / h, perform electrospinning, set the spinning voltage to 15kV, use a receiving plate with periodic vibration to collect the fibers, the vibration frequency of the receiving plate is 5Hz, adjust the receiving distance between the needle tip and the receiving plate to 10cm, use the periodic vibration of the receiving plate to induce the jet to spiral coil before solidification, place the entire spinning process in a temperature and humidity control chamber, control the ambient temperature to 20℃, the relative humidity to 40%, the spinning time to last 4h, form a spiral nanofiber with a fiber diameter of 30nm and a spiral diameter ratio of 10:1, forming a three-dimensional fiber network; Step 4: Dry the spiral nanofibers at 80℃ for 12 hours, and then hot-press them at 140℃ and 0.5MPa for 300 seconds to form a stable cross-linked network between the fibers. After natural cooling, the nanofiber air purification filter paper is obtained.

[0015] Example 2: A method for preparing an ultra-high efficiency, low resistance nanofiber air purification filter paper, comprising the following steps: Step 1: Disperse 5g of fumed silica nanoparticles in 200mL of anhydrous ethanol and sonicate for 30min. Under mechanical stirring, slowly add 0.5g of KH-550 to the dispersion and react in a 60℃ water bath for 6h. After the reaction is complete, collect the modified silica nanoparticles by centrifugation, wash them three times with ethanol, and dry them in a vacuum drying oven at 80℃ for 12h to obtain nano-silica modified with silane coupling agent. Step 2: Mix 2g of polyvinylidene fluoride, 0.45g of the above-mentioned modified nano-silica with a particle size of 55nm and 18g of tetrahydrofuran. Stir at 500rpm for 15h at 40℃, and then treat with ultrasonic power of 500W for 75min to make the modified nano-silica uniformly dispersed and in-situ composite in the polyvinylidene fluoride body to obtain the composite spinning solution. Step 3: Inject the composite spinning solution into a 10mL syringe, install a 21G stainless steel flat-tipped needle as the spinning nozzle, fix the syringe on the feed pump, set the feed speed to 1.75mL / h, perform electrospinning, set the spinning voltage to 25kV, use a receiving plate with periodic vibration to collect the fibers, the vibration frequency of the receiving plate is 27.5Hz, adjust the receiving distance between the needle tip and the receiving plate to 17.5cm, use the periodic vibration of the receiving plate to induce the jet to spiral coil before solidification, place the entire spinning process in a temperature and humidity control chamber, control the ambient temperature to 22.5℃, the relative humidity to 52.5%, and the spinning time to last for 4h, forming helical nanofibers with a fiber diameter of 45nm and a helix diameter ratio of 20:1, forming a three-dimensional fiber network; Step 4: Dry the spiral nanofibers at 80°C for 12 hours, and then hot-press them at 150°C and 2.75 MPa for 200 seconds to form a stable cross-linked network between the fibers. After natural cooling, nanofiber air purification filter paper is obtained.

[0016] Example 3: A method for preparing an ultra-high efficiency, low resistance nanofiber air purification filter paper, comprising the following steps: Step 1: Disperse 5g of fumed silica nanoparticles in 200mL of anhydrous ethanol and sonicate for 30min. Under mechanical stirring, slowly add 0.5g of KH-550 to the dispersion and react in a 60℃ water bath for 6h. After the reaction is complete, collect the modified silica nanoparticles by centrifugation, wash them three times with ethanol, and dry them in a vacuum drying oven at 80℃ for 12h to obtain nano-silica modified with silane coupling agent. Step 2: Mix 2g of polyvinylidene fluoride, 0.8g of the above-mentioned modified nano-silica with a particle size of 100nm and 18g of tetrahydrofuran. Stir at 800rpm for 6h at 60℃, and then treat with ultrasonic power of 800W for 30min to make the modified nano-silica uniformly dispersed and in-situ composite in the polyvinylidene fluoride body to obtain the composite spinning solution. Step 3: Inject the composite spinning solution into a 10mL syringe, install a 21G stainless steel flat-tipped needle as the spinning nozzle, fix the syringe on the feed pump, set the feed speed to 3mL / h, perform electrospinning, set the spinning voltage to 35kV, use a receiving plate with periodic vibration to collect the fibers, the vibration frequency of the receiving plate is 50Hz, adjust the receiving distance between the needle tip and the receiving plate to 25cm, use the periodic vibration of the receiving plate to induce the jet to spiral coil before solidification, place the entire spinning process in a temperature and humidity control chamber, control the ambient temperature to 25℃, the relative humidity to 65%, the spinning time to last 4h, form a spiral nanofiber with a fiber diameter of 60nm and a spiral diameter ratio of 30:1, forming a three-dimensional fiber network; Step 4: Dry the spiral nanofibers at 80°C for 12 hours, and then hot-press them at 160°C and 5MPa for 100 seconds to form a stable cross-linked network between the fibers. After natural cooling, nanofiber air purification filter paper is obtained.

[0017] Comparative Example 1: The difference between this comparative example and Example 1 is that a static metal plate receiver is used instead of a receiving plate, while the remaining steps are the same as in Example 1.

[0018] Step 1: Disperse 5g of fumed silica nanoparticles in 200mL of anhydrous ethanol and sonicate for 30min. Under mechanical stirring, slowly add 0.5g of KH-550 to the dispersion and react in a 60℃ water bath for 6h. After the reaction is complete, collect the modified silica nanoparticles by centrifugation, wash them three times with ethanol, and dry them in a vacuum drying oven at 80℃ for 12h to obtain nano-silica modified with silane coupling agent. Step 2: Mix 2g of polyvinylidene fluoride, 0.1g of the above-mentioned modified nano-silica with a particle size of 10nm and 18g of N,N-dimethylformamide, stir at 200rpm for 24h at 20℃, and then treat with ultrasonic power of 200W for 120min to make the modified nano-silica uniformly dispersed and in-situ composite in the polyvinylidene fluoride body to obtain the composite spinning solution; Step 3: Inject the composite spinning solution into a 10mL syringe, install a 21G stainless steel flat-tipped needle as the spinning nozzle, fix the syringe on the feed pump, set the feed speed to 0.5mL / h, perform electrospinning, set the spinning voltage to 15kV, use a static metal plate receiver to collect fibers, adjust the receiving distance between the needle tip and the static metal plate receiver to 10cm, place the entire spinning process in a temperature and humidity control chamber, control the ambient temperature to 20℃ and the relative humidity to 40%, and the spinning time to last for 4h, forming a fiber network with a fiber diameter of approximately 30nm; Step 4: Dry the nanofibers at 80℃ for 12 hours, then hot-press them at 140℃ and 0.5MPa for 300 seconds to form a stable cross-linked network between the fibers. After natural cooling, the nanofiber air purification filter paper is obtained.

[0019] Comparative Example 2: The difference between this comparative example and Example 1 is that the nano-rigid ions were not modified, while the remaining steps were the same as in Example 1.

[0020] A method for preparing an ultra-high efficiency, low resistance nanofiber air purification filter paper includes the following steps: Step 1: Mix 2g of polyvinylidene fluoride, 0.1g of unmodified nano-silica with a particle size of 10nm and 18g of N,N-dimethylformamide. Stir at 200rpm for 24h at 20℃, and then treat with ultrasonic power of 200W for 120min to uniformly disperse the unmodified nano-silica and in situ composite it into the polyvinylidene fluoride body to obtain the composite spinning solution. Step 2: Inject the composite spinning solution into a 10mL syringe, install a 21G stainless steel flat-tipped needle as the spinning nozzle, fix the syringe on the feed pump, set the feed speed to 0.5mL / h, perform electrospinning, set the spinning voltage to 15kV, use a receiving plate with periodic vibration to collect the fibers, the vibration frequency of the receiving plate is 5Hz, adjust the receiving distance between the needle tip and the receiving plate to 10cm, use the periodic vibration of the receiving plate to induce the jet to spiral coil before solidification, place the entire spinning process in a temperature and humidity control chamber, control the ambient temperature to 20℃, the relative humidity to 40%, the spinning time to last 4h, form a spiral nanofiber with a fiber diameter of 30nm and a spiral diameter ratio of 10:1, forming a three-dimensional fiber network; Step 3: Dry the spiral nanofibers at 80℃ for 12 hours, and then hot-press them at 140℃ and 0.5MPa for 300 seconds to form a stable cross-linked network between the fibers. After natural cooling, the nanofiber air purification filter paper is obtained.

[0021] Performance testing 1. Filtration performance test The filtration performance of air purification filter paper was tested in accordance with GB / T 14295-2019.

[0022] Table 1 Filtration performance test results

[0023] As shown in Table 1, the filter papers of Examples 1-3 achieved a breakthrough balance between PM0.3 filtration efficiency and initial pressure drop, with quality factor (QF) values ​​significantly higher than those of the comparative examples. This superior performance stems from the synergistic effect of helical modification and modified nanoparticles: the periodic vibration of the receiving plate induces the formation of helical nanofibers, constructing a three-dimensional elastic network with high porosity, providing a low-resistance channel for airflow while extending the particle capture path; silane-modified nano-SiO2 is uniformly dispersed and in-situ composited within the fibers, improving fiber stiffness while preventing pore blockage, allowing the low-resistance advantage of the helical structure to be fully utilized.

[0024] Comparative Example 1 uses a static receiving plate, which cannot form a spiral structure. The tight stacking of straight fibers causes a sharp increase in pressure drop to 62 Pa, and the quality factor drops to 0.074 Pa⁻¹. Comparative Example 2 uses unmodified nanoparticles, which agglomerate and block some pores, reducing the filtration efficiency to 99.990%, the pressure drop to 53 Pa, and the quality factor to only 0.068 Pa⁻¹. The data from the two comparative examples demonstrate that without a spiral structure or without modified particle reinforcement, it is impossible to achieve a breakthrough in high efficiency and low resistance, highlighting the indispensability of the synergistic effect of this invention.

[0025] 2 Mechanical property testing The mechanical properties of air purification filter paper were tested in accordance with the GB / T 40353-2021 standard.

[0026] Table 2 Mechanical Performance Test Results

[0027] As shown in Table 2, in Examples 1-3, as the amount of modified nano-SiO2 added increased from 5% to 40%, the flexural strength increased from 15.6 MPa to 35.5 MPa, the flexural modulus increased from 1.24 GPa to 3.12 GPa, and the elastic recovery rate reached as high as 92.5%-96.4%. This is due to the synergistic enhancement of the modified particles and the helical structure: the silane-modified nanoparticles form a strong interfacial bond with the polyvinylidene fluoride body, which is uniformly dispersed inside the fiber, effectively transferring stress and improving the intrinsic stiffness of the fiber; the helical structure disperses the deformation throughout the helical coil when under stress, and after the external force is unloaded, the elastic energy storage drives the fiber to return to its original configuration. The two work together to achieve a unity of high strength and high elasticity.

[0028] Although Comparative Example 1 used modified particles, the straight fibers lacked the deformation dispersion and elastic recovery mechanism of the helical structure, resulting in an elastic recovery rate of only 88.3%. Comparative Example 2, while possessing a helical structure, suffered from poor dispersion of unmodified particles and weak interfacial bonding, failing to effectively transfer stress, resulting in a flexural strength of only 9.8 MPa and an elastic recovery rate of only 85.7%. The mechanical properties of both comparative examples were significantly inferior to those of Example 1, demonstrating that the helical structure is responsible for deformation dispersion and elastic recovery, while the modified particles are responsible for improving intrinsic stiffness; only through their synergy can excellent mechanical properties be achieved.

[0029] 3. Breathability test Cut a circular sample with a diameter of 80 mm and place it in a standard temperature and humidity environment (temperature: 20±2℃, relative humidity: 65%±4%) for at least 24 hours to ensure that the moisture content of the sample reaches equilibrium before testing. Then, using a calibrated digital fabric air permeability meter, the sample is clamped flat and tightly in the test head under a fixed pressure difference of 100 Pa. The test is started so that the airflow passes vertically through the sample. The instrument automatically measures and records the airflow per unit time, and the final result is the average air permeability (unit: mm / s) of at least three valid samples.

[0030] Table 3. Results of air permeability test

[0031] As shown in Table 3, the air permeability of Examples 1-3 (19.7-28.6 mm / s) is significantly higher than that of Comparative Example 1 (12.2 mm / s), proving that the filter paper of the present invention provides a smooth, low-resistance channel for airflow. This is due to the in-situ composite reinforcement mechanism of the high-porosity network of the spiral structure and the modified particles: the spiral nanofibers intertwine to form a three-dimensional structure similar to a "spring bed," with a large number of interconnected pores retained between the fibers; the silane-modified nanoparticles are uniformly dispersed and in-situ composited inside the fibers, and the fiber surface is smooth, minimizing the blockage of the inherent pores between the fibers, so that the low-resistance channel can be completely preserved.

[0032] Comparative Example 1 uses a static receiving plate with tightly stacked straight fibers, resulting in low porosity and mostly closed pores. Its air permeability is only 12.2 mm / s, less than 55% of that of Example 1. Comparative Example 2 uses unmodified nanoparticles. These particles are unevenly dispersed within the fibers and easily aggregate. The aggregates protrude from the fiber surface or deposit in the fiber gaps, blocking some pore channels. Its air permeability (18.3 mm / s) is lower than that of Example 1 (22.5 mm / s). The spiral structure ensures high porosity and channel connectivity, while the uniform dispersion of the modified particles achieves "enhanced without reducing porosity." These two factors work synergistically to enable the filter paper of this invention to achieve both high-efficiency filtration and excellent air permeability.

[0033] 4. Microscopic morphology test The microstructure of nanofiber air purification filter paper was characterized using field emission scanning electron microscopy. The prepared filter paper samples were cut into 5mm × 5mm pieces, adhered to the sample stage using conductive tape, and then subjected to ion sputtering gold sputtering for 90 seconds to enhance the conductivity of the samples. Observations were performed at an accelerating voltage of 5kV and a working distance of 8-10mm, with images acquired at magnifications of 5000x, 20000x, and 50000x to record the helical morphology and three-dimensional network structure characteristics of the fibers.

[0034] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing an ultra-high efficiency, low resistance nanofiber air purification filter paper, characterized in that, Includes the following steps: Step 1: Mix polyvinylidene fluoride with nano-silica modified with silane coupling agent in an organic solvent. After stirring and ultrasonic treatment, the modified nano-silica is uniformly dispersed and in situ composited in the polyvinylidene fluoride body to obtain a composite spinning solution. Step 2: Inject the composite spinning solution into the injection pump for electrospinning. Use a receiving plate with periodic vibration to collect the fibers. The periodic vibration of the receiving plate induces the jet to spiral coil before solidification, forming helical nanofibers with a diameter of 30-60 nm and a helix diameter ratio of (10-30):1, which constitute a three-dimensional fiber network. The frequency of the periodic vibration is 5-50 Hz. Step 3: Dry the spiral nanofibers and hot-press them at 140-160℃ and 0.5-5MPa for 100-300s to form a stable cross-linked network between the fibers, thus obtaining nanofiber air purification filter paper. The spiral nanofibers and the modified nano-silica in situ composite inside the fibers work synergistically to maintain high porosity while extending the particle capture path by utilizing the elastic buffer of the spiral structure, and improving the fiber stiffness with the help of modified nano-silica, thereby achieving a balance between ultra-high efficiency filtration and low resistance and high structural stability.

2. The method for preparing the ultra-high efficiency, low resistance nanofiber air purification filter paper according to claim 1, characterized in that, In step 1, the amount of nano-silica modified with silane coupling agent is 5%-40% of the mass of polyvinylidene fluoride, and the particle size is 10-100 nm.

3. The method for preparing the ultra-high efficiency, low resistance nanofiber air purification filter paper according to claim 1, characterized in that, The stirring conditions in step 1 are 20-60℃ and 200-800rpm for 6-24h; the ultrasonic treatment power is 200-800W and the duration is 30-120min.

4. The method for preparing the ultra-high efficiency, low resistance nanofiber air purification filter paper according to claim 1, characterized in that, The organic solvent in step 1 is N,N-dimethylformamide or tetrahydrofuran.

5. The method for preparing the ultra-high efficiency, low resistance nanofiber air purification filter paper according to claim 1, characterized in that, In step 2, electrospinning is carried out in an environment with a relative humidity of 40%-65%, a spinning voltage of 15-35kV, a feeding rate of 0.5-3mL / h, and a receiving distance of 10-25cm.

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