Composite nanofiber material, method of preparation and use thereof

Abstract

The application belongs to the technical field of filter materials, and particularly relates to a composite nanofiber material, a preparation method and application thereof. The application discloses a composite nanofiber material, which is prepared from a spinning solution through electrostatic spinning, and the spinning solution comprises the following raw material components by weight: polylactic acid: 5-30 wt%, cellulose acetate: 5-30 wt%, a surfactant: 0.001-1 wt%, a conductivity regulator: 0.001-0.5 wt%, and a solvent: 60-90 wt%. By adding cellulose acetate, the surfactant and the conductivity regulator, the heat resistance and the filtration performance of the composite nanofiber material are improved. The prepared composite nanofiber material has good biodegradability, good heat resistance, good filtration performance, natural antibacterial property, low cost and simple operation, and is suitable for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of filtration materials technology, specifically relating to a composite nanofiber material, its preparation method, and its application. Background Technology

[0002] Electrospinning is a simple and efficient technique for preparing nanofibers. Its principle is as follows: in a high-voltage electric field, the charged spinning solution is stretched and refined by the electric field force, accompanied by solvent evaporation, and finally deposited on a receiving device to form a nanofiber membrane. Electrospun nanofibers possess ultra-high specific surface area and porosity, three-dimensional interconnected nanoscale pores, and nanoscale fiber diameter, enabling the prepared nanofiber filter materials to exhibit excellent air and water filtration performance.

[0003] Chinese patent CN114225711A discloses "an electrospun nanofiber membrane and its preparation method and application." This method involves co-spinning polylactic acid and cellulose acetate in a solvent. Cellulose acetate improves the mechanical strength of the nanofiber membrane and also adsorbs heavy metal ions and pigments. The nanofiber membrane prepared by electrospinning can effectively filter impurities below the micrometer scale, exhibiting good water permeability, hydrolysis resistance, biodegradability, and swelling resistance, making it suitable for manufacturing durable, long-lasting filter materials. However, it suffers from drawbacks such as low conductivity of the spinning solution, inability to further refine the fiber diameter, low spinning efficiency, dense fiber membrane, low porosity, and high filtration resistance. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, a composite nanofiber material, its preparation method, and its application are provided. This material is biodegradable, has good heat resistance, good filtration performance, and natural antibacterial properties. The preparation method is convenient to operate and low in cost.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] The first objective of this invention is to provide a composite nanofiber material, which is prepared by electrospinning from a spinning solution, wherein the spinning solution comprises the following raw material components by weight:

[0007] Polylactic acid: 5-30wt%

[0008] Cellulose acetate: 5-30 wt%

[0009] Surfactant: 0.001-1 wt%

[0010] Conductivity modifier: 0.001-0.5wt%

[0011] Solvent: 60-90 wt%.

[0012] Further, the surfactant is one or more of the following: polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monopalmitate, dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, octadecyldimethylbenzylammonium chloride, tetrabutylammonium chloride, sodium dodecylbenzenesulfonate, or sodium dodecyl sulfate.

[0013] Furthermore, the conductivity modifier is a soluble organic salt or an inorganic salt.

[0014] Furthermore, the soluble inorganic salt is one or more of the following: sodium chloride, potassium chloride, lithium chloride, calcium chloride, and magnesium chloride.

[0015] Further, the solvent includes one or more of the following: acetone, dichloromethane, chloroform, DMF, DMAc, hexafluoroisopropanol, formic acid, acetic acid, and trifluoroacetic acid.

[0016] A second objective of this invention is to provide a method for preparing a composite nanofiber material, comprising the steps of:

[0017] S1. Dissolve polylactic acid, cellulose acetate, surfactant and conductivity modifier in a solvent, heat and stir until completely dissolved, let stand to defoam, and obtain spinning solution;

[0018] S2. The spinning solution prepared in step S1 is loaded into the liquid storage device of the electrospinning machine, and electrospinning is performed to deposit nanofibers on the biodegradable nonwoven fabric substrate.

[0019] S3. Dry the nanofiber membrane prepared in step S2 to remove residual solvent, and roll it up to obtain the composite nanofiber membrane.

[0020] Further, in step S1, the spinning voltage is 10-70kV for the spinning electrode and -1-20kV for the receiving electrode; the ambient temperature is 25-45℃ and the humidity is 20-40%.

[0021] Furthermore, in step S2, the biodegradable receiving substrate is a nonwoven fabric made of biodegradable materials, including but not limited to cotton, linen, silk, wool, viscose fiber needle-punched and spunlace nonwoven fabrics, and heat-resistant modified PLA, PBAT, PBS, PBSA, PPC, PHA, PGA spunbond, meltblown, spunlace, needle-punched, and hot-air nonwoven fabrics.

[0022] Furthermore, in step S1, the conductivity of the spinning solution is 50-200 μS / cm.

[0023] A third objective of this invention is to provide a composite nanofiber material for use as a material for wastewater filtration or air filtration.

[0024] The beneficial effects of this invention are:

[0025] 1. All materials used in this invention are biodegradable, and the products are completely biodegradable and do not pollute the environment after disposal; polylactic acid hydrolyzes to be acidic, and cellulose acetate molecules contain a large number of hydroxyl groups with good hydrophilicity. The composite nanofibers have better degradability than single polylactic acid nanofibers or cellulose acetate nanofibers.

[0026] 2. Fiber acetate has high heat resistance. The polylactic acid / cellulose acetate composite nanofiber in this invention has better heat resistance than pure polylactic acid nanofiber, which broadens the application range of polylactic acid nanofiber and increases its service life.

[0027] 3. The synergistic effect of surfactants and conductivity modifiers in the spinning solution formulation of the present invention results in polylactic acid / cellulose acetate composite nanofiber membranes with smaller and more uniform fiber diameters, higher spinning efficiency, higher fiber membrane porosity, lower resistance, and more efficient filtration compared to conventional nanofiber membranes.

[0028] 4. In the spinning solution formulation of the present invention, since polylactic acid has natural weak acidity and antibacterial properties, the prepared polylactic acid / cellulose acetate composite nanofiber membrane also has natural antibacterial properties.

[0029] 5. In the preparation method of the present invention, the organic solvents used are collected and processed in a closed loop at each production stage, and then separated, purified and reused in a solvent recovery device. There is no harmful solvent discharge, which is a green and environmentally friendly process. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] Figure 1 This is a scanning electron microscope image of the nanofibers prepared in Example 1. Detailed Implementation

[0032] In this application, all raw materials are commercially available, and the sources of some of these raw materials are shown below:

[0033] Table 1 Sources of Some Raw Materials

[0034]

[0035] This invention provides a composite nanofiber material, its preparation method, and its application. Specifically, it provides a biodegradable polylactic acid / cellulose acetate composite nanofiber filter material, its preparation method, and its application, in order to solve the defects of existing nanofiber membranes, such as non-degradability, poor heat resistance, difficulty in refining fibers, low spinning efficiency, low porosity of fiber membranes, and high filtration resistance.

[0036] Polylactic acid (PLA), also known as polylactide, is a semi-crystalline thermoplastic material produced by the ring-opening polymerization of lactic acid and lactide. It possesses relatively good mechanical properties, solubility, biocompatibility, and biodegradability. However, PLA has poor thermal stability, with a glass transition temperature around 60℃ and a melting point around 175℃. One of the main drawbacks of its electrospun nanofibers is their relatively low heat resistance, which significantly limits their applications. Cellulose acetate (CA) is a biocompatible benign derivative of cellulose and one of the most abundant biopolymers on Earth. It is produced through esterification of green, environmentally friendly, and renewable wood or cotton fibers with acetic acid. It exhibits biodegradability, solubility, high transparency, and good hydrophilicity. Cellulose acetate has good thermal stability, with a glass transition temperature around 185℃ and a melting point between 230℃ and 300℃. By adjusting the ratio of polylactic acid (PLA) to cellulose acetate, the glass transition temperature of PLA / cellulose acetate composite nanofibers can be easily adjusted within a range of 60-185℃. PLA / cellulose acetate composite nanofibers exhibit better heat resistance than pure PLA nanofibers.

[0037] Therefore, a method for preparing biodegradable polylactic acid / cellulose acetate composite nanofibers is provided, the process flow of which is as follows: Figure 1 As shown, it includes the following steps:

[0038] S1. Dissolve polylactic acid, cellulose acetate, surfactant and conductivity modifier in a solvent, heat and stir until completely dissolved, let stand to defoam, and obtain spinning solution;

[0039] S2. The spinning solution prepared in step S1 is loaded into the liquid storage device of the electrospinning machine, and electrospinning is carried out under certain spinning environment temperature, humidity and spinning voltage to deposit nanofibers on the biodegradable nonwoven fabric substrate.

[0040] S3. The nanofiber membrane prepared in step S2 is dried at a certain temperature to remove residual solvent, and then wound into a roll to obtain the composite nanofiber membrane.

[0041] S4. The volatile organic solvents from steps S1, S2 and S3 are transported in a closed loop to a solvent recovery device for separation and purification. The purified solvents can be reused in step S1.

[0042] In step S1, the surfactant is used to reduce the surface tension of the spinning solution, which helps the spinning droplets overcome the surface tension and form a spinning jet. It also prevents fiber beading and results in more uniform fiber diameter. In step S1, the conductivity regulator significantly increases the conductivity of the spinning solution, increases the charge on the spinning jet, and thus increases the electric field pulling force on the spinning jet. This is beneficial for increasing the jet velocity, reducing fiber diameter, and also for increasing the charge on the resulting fibers. This results in larger electrostatic repulsion between the fibers, making them fluffy, with high porosity and lower filtration resistance. Specifically, the conductivity regulator is a soluble organic or inorganic salt, wherein the soluble inorganic salt is one or more of sodium chloride, potassium chloride, lithium chloride, calcium chloride, and magnesium chloride. Meanwhile, the surfactant and conductivity modifier can work synergistically to make the prepared polylactic acid / cellulose acetate composite nanofiber membrane smaller and more uniform in fiber diameter, with higher spinning efficiency, higher fiber membrane porosity, and higher efficiency and lower resistance compared to conventional nanofiber membranes. Specifically, the surfactant is one or more of the following: polyoxyethylene dehydrated sorbitan monooleate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monopalmitate, dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, octadecyldimethylbenzylammonium chloride, tetrabutylammonium chloride, sodium dodecylbenzenesulfonate, or sodium dodecyl sulfate.

[0043] In step S2, the biodegradable nonwoven fabric substrate includes, but is not limited to, cotton, linen, silk, wool, viscose fiber needle-punched and spunlace nonwoven fabrics, heat-resistant modified PLA, PBAT, PBS, PBSA, PPC, PHA, PGA spunbond, meltblown, spunlace, needle-punched, and hot-air nonwoven fabrics. Specifically, the substrate can be selected according to the actual production needs.

[0044] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the invention.

[0045] Example 1:

[0046] Spinning solution weight raw material composition:

[0047] Polylactic acid 10wt%

[0048] 10wt% cellulose acetate

[0049] Surfactant: Polyoxyethylene dehydrated sorbitan monooleate 0.05wt%

[0050] Conductivity modifier: Sodium chloride 0.01wt%

[0051] Solvent: 79.94%, of which chloroform / DMF (2:1, wt)

[0052] The solvent consists of chloroform and DMF in a weight ratio of 2:1.

[0053] Preparation method of composite nanofiber materials:

[0054] S1. Dissolve the above raw materials in a solvent, heat and stir until completely dissolved, let stand to defoam, and obtain a spinning solution;

[0055] S2. The spinning solution prepared in step S1 is loaded into the liquid storage device of the electrospinning machine. Electrospinning is carried out under the following conditions: spinning environment temperature of 35℃, humidity of 40%, conductivity of spinning solution of 80us / cm, spinning head voltage of 25kv and receiving end voltage of -5kv. Nanofibers are deposited on the pure cotton spunlace nonwoven fabric substrate.

[0056] S3. The nanofiber membrane prepared in step S2 is dried in an infrared oven at 45°C to remove residual solvent, and then rolled up to obtain polylactic acid / cellulose acetate composite nanofiber filter material.

[0057] S4. The volatile organic solvents from steps S1, S2 and S3 are transported in a closed loop to a solvent recovery device for separation and purification. The purified solvents can be reused in step S1.

[0058] Example 2:

[0059] Spinning solution weight raw material composition:

[0060] Polylactic acid 5wt%

[0061] 15wt% cellulose acetate

[0062] Surfactant: Sodium dodecylbenzenesulfonate 0.05wt%

[0063] Conductivity modifier: Lithium chloride 0.01 wt%

[0064] Solvent: 79.94%, of which chloroform / DMF (2:1, wt)

[0065] The solvent consists of chloroform and DMF in a weight ratio of 2:1.

[0066] Preparation method of composite nanofiber materials:

[0067] S1. Dissolve the above raw materials in a solvent, heat and stir until completely dissolved, let stand to defoam, and obtain a spinning solution;

[0068] S2. The spinning solution prepared in step S1 is loaded into the electrospinning machine storage device, and electrospinning is carried out under the following conditions: spinning environment temperature 35℃, humidity 40%, spinning solution conductivity 80us / cm, spinning head voltage 25kv and receiving end voltage -5kv. Nanofibers are deposited on the viscose hydroentangled nonwoven fabric substrate.

[0069] S3. Fiber drying: The nanofiber membrane prepared in step S2 is dried in an infrared oven at 65°C to remove residual solvent, and then rolled up to obtain polylactic acid / cellulose acetate composite nanofiber filter material.

[0070] S4. The volatile organic solvents from steps S1, S2 and S3 are transported in a closed loop to a solvent recovery device for separation and purification. The purified solvents can be reused in step 1.

[0071] Example 3:

[0072] Spinning solution weight raw material composition:

[0073] Polylactic acid 20wt%

[0074] 5wt% cellulose acetate

[0075] Surfactant: Dodecyltrimethylammonium bromide 0.02 wt%

[0076] Conductivity modifier: 0.05 wt% calcium chloride

[0077] Solvent: 74.93%, of which dichloromethane / DMAc (3:2, wt)

[0078] The solvent consists of dichloromethane and DMAc in a weight ratio of 3:2.

[0079] Preparation method of composite nanofiber materials:

[0080] S1. Dissolve the above raw materials in a solvent, heat and stir until completely dissolved, let stand to defoam, and obtain a spinning solution;

[0081] S2. The spinning solution prepared in step S1 is loaded into the electrospinning machine storage device. Electrospinning is carried out under the following conditions: spinning environment temperature of 35°C, humidity of 30%, spinning solution conductivity of 120 μS / cm, spinning head voltage of 20 kV and receiving end voltage of -10 kV. Nanofibers are deposited on the viscose / cotton blend spunlace nonwoven fabric substrate.

[0082] S3. Fiber drying: The nanofiber membrane prepared in step S2 is dried in an infrared oven at 55°C to remove residual solvent, and then rolled up to obtain polylactic acid / cellulose acetate composite nanofiber filter material.

[0083] S4. Solvent Recovery: The volatile organic solvents from steps S1, S2 and S3 are transported in a closed loop to a solvent recovery device for separation and purification. The purified solvents can be reused in step S1.

[0084] Example 4:

[0085] Spinning solution weight raw material composition:

[0086] Polylactic acid 30wt%

[0087] 5wt% cellulose acetate

[0088] Surfactants: 0.5 wt% polyoxyethylene dehydrated sorbitan monooleate, 0.5 wt% dodecyltrimethylammonium bromide

[0089] Conductivity modifiers: 0.25 wt% calcium chloride, 0.25 wt% potassium chloride

[0090] Solvent: 63.5%, of which dichloromethane / DMAc (3:2, wt)

[0091] The solvent consists of dichloromethane and DMAc in a weight ratio of 3:2.

[0092] Preparation method of composite nanofiber materials:

[0093] S1. Dissolve the above raw materials in a solvent, heat and stir until completely dissolved, let stand to defoam, and obtain a spinning solution;

[0094] S2. The spinning solution prepared in step S1 is loaded into the electrospinning machine storage device. Electrospinning is carried out under the following conditions: spinning environment temperature 25℃, humidity 20%, spinning solution conductivity 50us / cm, spinning head voltage 10kv and receiving end voltage -1kv. Nanofibers are deposited on the viscose / cotton blend spunlace nonwoven fabric substrate.

[0095] S3. Fiber drying: The nanofiber membrane prepared in step S2 is dried in an infrared oven at 55°C to remove residual solvent, and then rolled up to obtain polylactic acid / cellulose acetate composite nanofiber filter material.

[0096] S4. Solvent Recovery: The volatile organic solvents from steps S1, S2 and S3 are transported in a closed loop to a solvent recovery device for separation and purification. The purified solvents can be reused in step S1.

[0097] Example 5:

[0098] Spinning solution weight raw material composition:

[0099] Polylactic acid 5wt%

[0100] 30wt% cellulose acetate

[0101] Surfactant: Polyoxyethylene dehydrated sorbitan monooleate 0.001 wt%

[0102] Conductivity modifier: 0.001 wt% calcium chloride

[0103] Solvent: 64.99%, of which dichloromethane / DMAc (3:2, wt)

[0104] The solvent consists of dichloromethane and DMAc in a weight ratio of 3:2.

[0105] Preparation method of composite nanofiber materials:

[0106] S1. Dissolve the above raw materials in a solvent, heat and stir until completely dissolved, let stand to defoam, and obtain a spinning solution;

[0107] S2. The spinning solution prepared in step S1 is loaded into the electrospinning machine storage device. Electrospinning is carried out under the following conditions: spinning environment temperature 45℃, humidity 25%, spinning solution conductivity 200us / cm, spinning head voltage 70kv and receiving end voltage -20kv. Nanofibers are deposited on the viscose / cotton blend spunlace nonwoven fabric substrate.

[0108] S3. Fiber drying: The nanofiber membrane prepared in step S2 is dried in an infrared oven at 55°C to remove residual solvent, and then rolled up to obtain polylactic acid / cellulose acetate composite nanofiber filter material.

[0109] S4. Solvent Recovery: The volatile organic solvents from steps S1, S2 and S3 are transported in a closed loop to a solvent recovery device for separation and purification. The purified solvents can be reused in step S1.

[0110] Comparative Example 1:

[0111] Unlike Example 1, the spinning solution did not contain cellulose acetate, but all other conditions were the same.

[0112] Comparative Example 2:

[0113] Unlike Example 1, polylactic acid was not added to the spinning solution, but all other conditions were the same.

[0114] Comparative Example 3:

[0115] Unlike Example 1, no surfactants and conductivity modifiers were added to the spinning solution, while all other conditions remained the same.

[0116] Comparative Example 4:

[0117] Unlike Example 1, no conductivity modifier was added to the spinning solution, while all other conditions remained the same.

[0118] Comparative Example 5:

[0119] Unlike Example 1, no surfactant was added to the spinning solution, but all other conditions were the same.

[0120] Analysis of experimental results:

[0121] 1. The temperature resistance of the nanofiber membranes prepared in Example 1 and Comparative Examples 1-2 was tested:

[0122] The nanofiber membranes were fixed onto glass slides with double-sided tape and placed in a heating oven. They were kept at 60℃, 90℃ and 120℃ for 10 min respectively. The changes in the appearance of the nanofiber membranes were observed and recorded. The results are shown in Table 2.

[0123] Table 2. Temperature resistance test of nanofiber membranes at different temperatures

[0124] temperature 60℃ 90℃ 120℃ Example 1 No deformation No deformation No deformation Comparative Example 1 Shrinkage deformation Shrinkage deformation Shrinkage deformation Comparative Example 2 No deformation No deformation No deformation

[0125] As can be seen from the results in Table 2, the polylactic acid / cellulose acetate (1:1) nanofiber membrane of Example 1 can withstand a temperature of up to 120°C without deformation or damage, which is close to the heat resistance of the cellulose acetate nanofiber membrane of Comparative Example 2; the polylactic acid nanofiber membrane of Comparative Example 1 without the addition of cellulose acetate has already undergone severe softening, shrinkage and deformation at 60°C.

[0126] 2. The particulate matter filtration efficiency, morphology, and fiber diameter of the nanofiber filter materials prepared in Examples 1-5 and Comparative Examples 3-5 were tested:

[0127] The filtration efficiency of nanofiber filter media for 0.3 μm sodium chloride particles was tested using a TSI8130A filter media tester at a flow rate of 32 L / min. Five points were tested in each group, and the average value was taken. The morphology of the nanofibers and the fiber diameter were observed and measured using a scanning electron microscope. The results are recorded in Table 3.

[0128] TSI8130A: Filtration efficiency testing instrument, made in the USA.

[0129] As can be seen from the results in Table 3, the filtration performance of Examples 1-5 is significantly better than that of Comparative Examples 3-5, and the fiber diameter is also smaller than that of Comparative Examples 3-5. Furthermore, comparing Comparative Examples 3-5, it can be seen that adding surfactants and conductivity modifiers can eliminate fiber bead formation; adding conductivity modifiers helps reduce fiber diameter; both surfactants and conductivity modifiers help improve the filtration efficiency of the filter media, with the conductivity modifier having the greatest effect; Example 1, which simultaneously adds both surfactants and conductivity modifiers, exhibits the best filtration performance, indicating that surfactants and conductivity modifiers have a synergistic effect in improving the filtration performance of this filter media.

[0130] Table 3. Particulate matter filtration efficiency, morphology, and fiber diameter tests of the nanofiber filter materials prepared in Examples 1-5 and Comparative Examples 3-5

[0131]

[0132]

[0133] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A composite nanofiber material, characterized in that, The composite nanofiber material is prepared by electrospinning from a spinning solution, and the spinning solution comprises the following raw material components by weight: Polylactic acid: 5-30wt% Cellulose acetate: 5-30 wt% Surfactant: 0.001-1 wt% Conductivity modifier: 0.001-0.5wt% Solvent: 60-90 wt%; The conductivity modifier is a soluble inorganic salt; The conductivity of the spinning solution is 50-200 μS / cm.

2. The composite nanofiber material according to claim 1, characterized in that, The surfactant is one or more of the following: polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monopalmitate, dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, octadecyldimethylbenzylammonium chloride, tetrabutylammonium chloride, sodium dodecylbenzenesulfonate, or sodium dodecyl sulfate.

3. The composite nanofiber material according to claim 1, characterized in that, The soluble inorganic salt is one or more of sodium chloride, potassium chloride, lithium chloride, calcium chloride, and magnesium chloride.

4. The composite nanofiber material according to claim 1, characterized in that, The solvent includes one or more of the following: acetone, dichloromethane, chloroform, DMF, DMAc, hexafluoroisopropanol, formic acid, acetic acid, and trifluoroacetic acid.

5. A method for preparing a composite nanofiber material, used to prepare the composite nanofiber material according to any one of claims 1-4, characterized in that: S1. Dissolve polylactic acid, cellulose acetate, surfactant and conductivity modifier in a solvent, heat and stir until completely dissolved, let stand to defoam, and obtain spinning solution; S2. The spinning solution prepared in step S1 is loaded into the liquid storage device of the electrospinning machine, and electrospinning is carried out under certain spinning environment temperature, humidity and spinning voltage to deposit nanofibers on the substrate. S3. The nanofibers prepared in step S2 are dried at a certain temperature to remove residual solvent, and then rolled up to obtain the composite nanofibers.

6. The method for preparing the composite nanofiber material according to claim 5, characterized in that: In step S1, the conductivity of the spinning solution is 50-200 μS / cm.

7. The method for preparing the composite nanofiber material according to claim 5, characterized in that: In step S2, the spinning voltage is 10-70kV for the spinning electrode and -1-20kV for the receiving electrode; the ambient temperature is 25-45℃ and the humidity is 20-40%.

8. The method for preparing the composite nanofiber material according to claim 5, characterized in that: In step S2, the substrate is a nonwoven fabric made of biodegradable material.

9. An application of a composite nanofiber material, characterized in that, The composite nanofiber material according to any one of claims 1-4 or the composite nanofiber material prepared by the preparation method according to any one of claims 5-8 can be used as a material for wastewater filtration or air filtration.

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