Preparation method and application of fluorine-containing nanofiber dispersion liquid

Abstract

The invention discloses a preparation method and application of fluorine-containing nanofiber dispersion liquid, biomass raw materials react in a fluorine-containing anhydride solution to obtain water-insoluble fluorine-containing biomass fibers, and the water-insoluble fluorine-containing biomass fibers are dispersed and dialyzed in a water system; and carrying out homogenization and ultrasonic treatment on the fluorine-containing biomass fiber water suspension, and centrifuging to obtain supernate, namely the biomass nanofiber dispersion liquid. The invention develops a method for preparing functionalized fluorine-containing nanofibers from waste biomass fibers through mild esterification pretreatment at the temperature of 65-100 DEG C; compared with typical TEMPO oxidation, the biomass nanofiber esterified with fluorine-containing anhydride has better functionalization and application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanofiber materials, and in particular relates to a preparation method of a fluorine-containing nanofiber dispersion and application thereof. Background Art

[0002] Biomass refers to the waste products of animals, plants, microorganisms, and their production, and is widely distributed. Chitin, a nitrogen-containing biomass material found extensively in the exoskeletons of insects and crustaceans, is the second most abundant biopolymer on Earth after cellulose, and the second most abundant polysaccharide on Earth. However, its extremely insoluble nature greatly limits its application as a biomass matrix. Natural chitin is abundant, inexpensive, and environmentally sustainable, and chemically modified chitin offers a wider range of value. Chitosan, a natural polymer obtained by deacetylation of chitin, possesses excellent properties such as biocompatibility, safety, and microbial degradability. It has been widely used in numerous fields, including medicine, food, chemicals, cosmetics, water treatment, metal extraction and recovery, and biomedicine, and has made significant progress.

[0003] Taking chitin nanofibers as an example, the main modification methods are usually as follows:

[0004] 1) Tsuguyuki S et al. selectively oxidized the C6 hydroxyl group on the surface of the chitin crystalline region into carboxyl groups through the TEMPO oxidation method, and then effectively isolated the chitin nanofibers with carboxyl groups (TOChNs) after homogenizing and ultrasonicating them in an aqueous system to prepare chitin nanofiber dispersions.

[0005] 2) Chitin is treated with concentrated alkali and high temperature for a long time to remove some of the acetyl groups at the C2 position, exposing more amino groups and increasing the number of amino groups on its surface. After homogenization and ultrasonic treatment under weak acidic conditions, chitin nanofibers with amino groups (DEChNs) can be obtained to prepare chitin nanofiber dispersions.

[0006] Modified chitin nanofibers possess numerous excellent properties, including a large specific surface area, high crystallinity, high hydrophilicity, high modulus, high strength, ultrafine structure, and high transparency. Furthermore, the hydroxyl and amino groups on chitin provide a variety of active sites for modification and crosslinking, making them an advantageous raw material for constructing biomass porous network hydrogel adsorbents. However, surface-modified chitin nanofibers lack specific application prospects. Summary of the Invention

[0007] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0008] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0009] One of the objectives of the present invention is to provide a method for preparing a fluorinated nanofiber dispersion. The method uses a fluorinated acid anhydride as a pretreatment agent. At a relatively mild temperature, the fiber raw material undergoes an esterification reaction with the fluorinated acid anhydride, resulting in the grafting of a large number of fluorinated groups onto the fiber surface. The fluorinated nanofiber dispersion is then obtained by mechanical dispersion and ultrasonic treatment.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for preparing a fluorine-containing nanofiber dispersion, comprising:

[0011] The fragmented cellulose or chitin is pre-cooled under low temperature conditions;

[0012] Adding fluorinated acid anhydride to the cellulose or chitin, allowing the mixture to react fully, adding alkali for repeated washing and centrifugation to remove unreacted acid anhydride, thereby obtaining a fluorinated cellulose or fluorinated chitin precipitate;

[0013] Taking the fluorinated cellulose or fluorinated chitin precipitate, dispersing it in a water system and dialyzing it to obtain a fluorinated cellulose or fluorinated chitin aqueous suspension;

[0014] The fluorinated cellulose or fluorinated chitin aqueous suspension is taken, the pH is adjusted to neutral or weakly alkaline, and then mechanically dispersed, ultrasonically treated, and centrifuged to remove precipitation to obtain a fluorinated cellulose nanofiber or chitin nanofiber dispersion.

[0015] As a preferred embodiment of the method for preparing the fluorine-containing nanofiber dispersion of the present invention, the cellulose is one or more of cotton cellulose, hemp cellulose, bamboo cellulose, wood cellulose, grass cellulose, and microcrystalline cellulose;

[0016] The chitin is one or more of crab shell chitin, shrimp shell chitin, and squid cartilage chitin.

[0017] As a preferred embodiment of the method for preparing the fluorine-containing nanofiber dispersion of the present invention, the low-temperature pre-cooling treatment is performed using liquid nitrogen or an ice bath.

[0018] As a preferred embodiment of the method for preparing the fluorine-containing nanofiber dispersion of the present invention, the fluorine-containing anhydride is one or more of trifluoroacetic anhydride, tetrafluorosuccinic anhydride, pentafluoropropionic anhydride, hexafluoroglutaric anhydride, heptafluorobutyric anhydride, trifluoromethanesulfonic anhydride, trifluoromethanesulfonic anhydride, perfluorobutylsulfonic anhydride, and nonafluorobutylsulfonic anhydride.

[0019] As a preferred embodiment of the method for preparing the fluorine-containing nanofiber dispersion of the present invention, the mass ratio of the cellulose or chitin to the fluorine-containing acid anhydride is 3:20-40.

[0020] As a preferred embodiment of the method for preparing the fluorine-containing nanofiber dispersion of the present invention, the reaction temperature is 65-100° C., the reaction time is 1-6 hours, and the stirring speed is 100-1000 r / min.

[0021] As a preferred embodiment of the method for preparing the fluorine-containing nanofiber dispersion of the present invention, the base is a hydroxide or a carbonate.

[0022] As a preferred embodiment of the method for preparing the fluorine-containing nanofiber dispersion of the present invention, the dialysis uses an 8-14 kDa dialysis bag, and the dialysis time is 1-2 days.

[0023] As a preferred embodiment of the method for preparing the fluorine-containing nanofiber dispersion of the present invention, wherein: the mechanical dispersion has a dispersion time of 5 to 10 minutes;

[0024] The ultrasonic treatment time is 30 to 60 minutes;

[0025] The centrifuge speed is 10000 r / min and the centrifugation time is 3 to 5 minutes.

[0026] Another object of the present invention is to provide the use of the fluorine-containing nanofiber dispersion obtained by the preparation method described above in nanofiber films and gel adsorbent materials.

[0027] Another object of the present invention is to provide a method for preparing fluorine-containing nanofiber hydrogel, comprising:

[0028] The fluorine-containing nanofiber dispersion obtained by the preparation method described above is fully mixed with gelatin and a cross-linking agent, and frozen to form a fluorine-containing nanofiber hydrogel;

[0029] The mass ratio of the fluorine-containing nanofiber dispersion to gelatin is 1:1-3.

[0030] Specifically, 1 mL (1-50 mg / mL) of fluorinated nanofiber dispersion was slowly added to 1 mL (1-100 mg / mL) of gelatin, and stirred at 300-800 rpm for 30-60 minutes until thoroughly mixed. 5-20 μL (0.5-2 mg / μL) of glutaraldehyde was slowly added, and stirred at 300-800 rpm for 30-60 minutes until thoroughly mixed. The uniformly mixed precursor solution was transferred to a custom mold and frozen at -20°C for 10-20 hours. After the precursor solution sol was formed, it was removed to obtain the F / G fluorinated nanofiber hydrogel.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention provides a method for preparing a fluorine-containing nanofiber dispersion by an esterification reaction between a fluorine-containing acid anhydride and fibers combined with mechanical ultrasonic dispersion. The prepared fluorine-containing nanofibers have carboxyl groups grafted onto the fiber surface through the esterification reaction between the fluorine-containing acid anhydride and the nanofibers, thereby increasing the repulsive force between the fibers and promoting the dispersibility of the fibers in an aqueous solution. The prepared fluorine-containing chitin nanofibers have a uniform size distribution and an average length of about 500 nm.

[0033] The reaction temperature of the present invention is relatively mild, and the reaction can occur at only 65-100° C., which saves energy consumption and reduces preparation costs. The method adopted is simple to operate and easy to realize industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0035] Figure 1 This is a transmission electron microscope (TEM) image of the fluorine-containing nanofibers prepared in Example 1.

[0036] Figure 2 The X-ray diffraction (XRD) patterns of the fluorine-containing nanofibers prepared in Examples 1 to 4 are shown.

[0037] Figure 3 The Fourier transform infrared spectrometer (FTIR) spectra of the fluorine-containing nanofibers prepared in Examples 1 to 4 are shown.

[0038] Figure 4 This is the X-ray photoelectron spectroscopy (XPS) spectrum of the fluorine-containing nanofibers prepared in Example 1.

[0039] Figure 5Li of different proportions of fluorine-containing nanofiber hydrogel prepared in Examples 5 to 8 and Comparative Example 1 + Adsorption data spectrum.

[0040] Figure 6 These are the compressive mechanical properties of the fluorine-containing nanofiber hydrogels prepared in different proportions in Examples 5 to 7 and Comparative Example 1.

[0041] Figure 7 These are the rheological properties of the fluorine-containing nanofiber hydrogels prepared in different proportions in Examples 5 to 7 and Comparative Example 1.

[0042] Figure 8 Li of nanofiber hydrogels prepared by different modification methods in Example 6 and Comparative Example 2 + Adsorption data spectrum. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0044] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0045] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0046] Unless otherwise specified, the raw materials used in the examples were purchased commercially.

[0047] The chitin raw material used in the embodiment of the present invention is chitin purified from crab shells.

[0048] Purification steps of crab shells:

[0049] The crab shells were soaked in a 1M NaOH solution for approximately 12 hours to remove protein, washed with distilled water until neutral, and then soaked in a 1M HCl solution for 12 hours to remove minerals. The shells were then washed with distilled water until neutral. This process was repeated three times to remove as much protein and minerals (primarily calcium) as possible. The shells were softened and washed to neutrality. The shells were then bleached in a 70°C waterbath in a fume hood for 2 hours, stirring intermittently. If bleaching was incomplete, the shells were washed to neutrality and bleached a second time. The purified shells were washed again to neutrality, crushed with a juicer, and stored in a sealed bag in a refrigerator at 4°C for two days to balance the moisture content. A sample was then taken to measure the moisture content using an infrared moisture analyzer and retained for future use.

[0050] Chitin can be purified from crab shells, shrimp shells, and squid parietal bones. The experimental method is the same as above and will not be repeated here.

[0051] Example 1

[0052] Preparation of fluorine-containing nanofiber dispersion: 150 mg dry weight chitin raw material is taken, the chitin raw material is pre-cooled with liquid nitrogen in a pressure tube, and then mixed with 1 g hexafluoroglutaric anhydride solution; the mixing process is stirred under low temperature conditions, and after mixing evenly, the mixture is transferred to a water bath and heated at 90°C for reaction, the reaction time is 1 hour, and the mechanical stirring speed is 1000 r / min; after the reaction is completed, the water-insoluble fluorine-containing chitin is washed with deionized water to fully wash away the unreacted anhydride to obtain a fluorine-containing chitin precipitate; the precipitate is water-insoluble fluorine-containing chitin, and water is taken. Insoluble fluorinated chitin is added to a water system and stirred thoroughly to obtain a fluorinated chitin suspension; the fluorinated chitin aqueous suspension is dialyzed in a dialysis bag with a specification of 8 to 14 kDa for 2 days; the pH of the dialyzed fluorinated chitin aqueous suspension is adjusted to approximately 10, and the suspension is subjected to nanofiber treatment; mechanical dispersion and ultrasonic treatment are repeated 4 to 6 times; the nanofiber-treated suspension is placed in a centrifuge at 10,000 r / min and centrifuged for 3 to 5 minutes, and the supernatant is the fluorinated chitin nanofiber dispersion.

[0053] According to the method provided by the present invention, the reaction time is 1 hour, but the system provided by the present invention is not limited thereto. The following examples are respectively described with reaction times of 2 hours, 4 hours, and 6 hours.

[0054] Example 2

[0055] The preparation method of the fluorine-containing nanofiber dispersion is the same as that of Example 2, wherein in Example 2, the reaction time of chitin and hexafluoroglutaric anhydride is 2 hours.

[0056] Example 3

[0057] The preparation method of the fluorine-containing nanofiber dispersion is the same as that of Example 2, wherein in Example 2, the reaction time of the chitin fiber and hexafluoroglutaric anhydride is 4 hours.

[0058] Example 4

[0059] The preparation method of the fluorine-containing nanofiber dispersion is the same as that of Example 2, wherein in Example 2, the reaction time of the chitin fiber and hexafluoroglutaric anhydride is 6 hours.

[0060] The products in Examples 1, 2, 3, and 4 were characterized by microscopic morphology. Figure 1 The morphology of the fluorine-containing nanofibers obtained under a transmission electron microscope (TEM) is shown in Figure 1. Figure 1 It can be seen that the fluorine-modified nanofibers still retain their fiber properties and their length is maintained at around 500 nm.

[0061] The internal structures of the products in Examples 1, 2, 3, and 4 were characterized. Figure 2 The X-ray diffraction (XRD) patterns of fluorine-containing nanofibers obtained at different reaction times are shown in Figure 2. Figure 2 The symbol CT refers to the raw material before fluorine modification. Figure 2 It can be seen that the fluorine-modified nanofibers still retain the original biomass crystalline structure, which shows that the fluorine modification process does not destroy the internal crystalline structure of the biomass fibers.

[0062] The internal structures of the products in Examples 1, 2, 3, and 4 were characterized. Figure 3 The following is the spectrum of fluorine-containing nanofibers obtained at different reaction times measured by Fourier infrared spectrometer (FTIR). Figure 3 It can be seen that the nanofibers modified with fluorine have the highest peaks at 1239 and 1207 cm -1 The appearance of the characteristic absorption peak of CF indicated that an esterification reaction occurred between the C6 hydroxyl groups of the nanofibers and the fluorination reagent, and the substituents were covalently bonded to chitin.

[0063] The internal structures of the products in Examples 1, 2, 3, and 4 were characterized. Figure 4 This is the spectrum of fluorine-containing nanofibers obtained under a reaction time of 1 hour measured by X-ray photoelectron spectroscopy (XPS). Figure 4 It can be seen that the fluorine-modified nanofibers show a characteristic peak of F at 688.08 eV, indicating that the fluorine-containing groups are successfully grafted onto the nanofiber surface.

[0064] Example 5

[0065] To prepare the fluorinated nanofiber hydrogel, 1 mL (25 mg, 25 mg / mL) of the nanofiber dispersion from Example 1 was slowly added with 1 mL (25 mg, 25 mg / mL) of gelatin. The mixture was stirred at 500 rpm for 30 minutes until thoroughly mixed. Glutaraldehyde (10 μL, 1 mg / μL) was then slowly added and stirred at 500 rpm for 30 minutes until thoroughly mixed. The homogeneously mixed precursor solution was transferred to a custom mold and frozen at -20°C for 14 hours. After the precursor solution sol was formed, it was removed to obtain a 1:1 F / G fluorinated nanofiber hydrogel.

[0066] Example 6

[0067] To prepare the fluorinated nanofiber hydrogel, 1 mL (16.7 mg, 16.7 mg / mL) of the fluorinated nanofiber dispersion from Example 1 was slowly added with 1 mL (33.3 mg, 33.3 mg / mL) of gelatin. The mixture was stirred at 500 rpm for 30 minutes until thoroughly mixed. Glutaraldehyde (1 mg, 1 mg / μL) was then slowly added and stirred at 500 rpm for 30 minutes until thoroughly mixed. The homogeneously mixed precursor solution was transferred to a custom mold and frozen at -20°C for 14 hours. After the precursor solution sol was formed, it was removed to obtain a 1:2 F / G fluorinated nanofiber hydrogel.

[0068] Example 7

[0069] To prepare the fluorinated nanofiber hydrogel, 1 mL (12.5 mg, 12.5 mg / mL) of the fluorinated nanofiber dispersion from Example 1 was slowly added with 1 mL (37.5 mg, 37.5 mg / mL) of gelatin. The mixture was stirred at 500 rpm for 30 minutes until fully mixed. Glutaraldehyde (1 mg, 1 mg / μL) was then slowly added and stirred at 500 rpm for 30 minutes until the glutaraldehyde was fully mixed. The uniformly mixed precursor solution was transferred to a custom mold and frozen at -20°C for 14 hours. After the precursor solution sol was formed, it was removed to obtain a 1:3 F / G fluorinated nanofiber hydrogel.

[0070] Example 8

[0071] To prepare the fluorinated nanofiber hydrogel, 1 mL (8.3 mg, 8.3 mg / mL) of the fluorinated nanofiber dispersion from Example 1 was slowly added with 1 mL (41.7 mg, 41.7 mg / mL) of gelatin, and stirred at 500 r / min for 30 min until fully mixed. Glutaraldehyde (1 mg, 1 mg / μL) was then slowly added, and stirred at 500 r / min for 30 min until the glutaraldehyde was fully mixed. The uniformly mixed precursor solution was transferred to a custom mold and frozen at -20°C for 14 h. After the precursor solution sol was formed, it was removed to obtain a 1:5 F / G fluorinated nanofiber hydrogel.

[0072] Comparative Example 1

[0073] To prepare the fluorinated nanofiber hydrogel, slowly add 1 mL of gelatin (50 mg, 50 mg / mL) to 1 mL of pure water and stir at 500 rpm for 30 minutes until thoroughly mixed. Slowly add 10 μL of glutaraldehyde (1 mg, 1 mg / μL) and stir at 500 rpm for 30 minutes until thoroughly mixed. The mixed precursor solution was transferred to a custom mold and frozen at -20°C for 14 hours. After the precursor solution sol formed, it was removed to obtain a 0:1 F / G fluorinated nanofiber hydrogel.

[0074] Comparative Example 2

[0075] Preparation of carboxylated chitin nanofibers (TOChNs): 1 g of dry chitin raw material was suspended in 200 mL of pure water, 0.01 mmol of TEMPO reagent (4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyl 1-oxyl free radical) 0.016 g and 0.1 g of sodium bromide were added, and the mixture was stirred until the TEMPO dissolved. Then, sodium hypochlorite (8 mmol) was added, and the pH was adjusted to 10. The reaction was carried out for 2 h, and the mixture was dialyzed for 2 days in an 8-14 kDa dialysis bag until neutrality was obtained to obtain a carboxylated chitin suspension. The suspension was nano-treated by mechanical dispersion and ultrasonic treatment, repeated 4-6 times. The nano-treated suspension was placed in a centrifuge at 10,000 r / min and centrifuged for 3-5 minutes. The supernatant was the carboxylated chitin nanofiber dispersion, which was concentrated by rotary evaporation and freeze-dried to obtain nanofibers referred to as TOChNs.

[0076] Preparation of carboxyl-containing nanofiber TOChNs hydrogel: 1 mL of carboxyl-containing nanofiber TOChNs dispersion (25 mg, 25 mg / mL) was slowly added to 1 mL of gelatin (25 mg, 25 mg / mL), and stirred at 500 r / min for 30 min until thoroughly mixed. 10 μL of glutaraldehyde (1 mg, 1 mg / μL) was slowly added and stirred at 500 r / min for 30 min until thoroughly mixed. The mixed precursor solution was transferred to a custom mold and frozen at -20°C for 14 h. After the precursor solution sol was formed, it was removed to obtain a 1:1 carboxyl-containing nanofiber TOChNs / G hydrogel.

[0077] The adsorption capacity test was performed on the products in Examples 5 to 8 and Comparative Example 1. Figure 5 Li of different proportions of fluorine-containing nanofiber hydrogels + Adsorption data spectrum, that is, the mass ratios of fluorine-containing nanofibers and gelatin are 0:1, 1:5, 1:3, 1:2, and 1:1 respectively. Figure 5 It can be seen that the adsorption capacity of the hydrogel with a high proportion of fluorine-containing nanofibers is significantly stronger than that of the hydrogel with a low proportion of fluorine-containing nanofibers, indicating that the fluorine-containing nanofibers have a better adsorption capacity on Li + The adsorption direction has potential application prospects.

[0078] The hydrogels in Examples 5 to 7 and Comparative Example 1 were subjected to compression strength tests. Figure 6 This is the compressive strength spectrum of fluorine-containing nanofiber hydrogels with different proportions. Figure 6 It can be seen that compared with the hydrogel without fluorine-containing nanofibers, the compressive strength of the hydrogel containing a certain proportion of fluorine-containing nanofibers is significantly increased, indicating that fluorine-containing nanofibers can enhance the mechanical properties of hydrogel materials.

[0079] The hydrogels in Examples 5 to 7 and Comparative Example 1 were subjected to rheological strength tests. Figure 7 The rheological data of fluorine-containing nanofiber hydrogels with different proportions are shown in Figure 2. Figure 7 It can be seen that the storage modulus G' of the three groups of hydrogel materials is greater than the loss modulus G", indicating the typical elastic deformation characteristics of the hydrogel. In addition, the elastic modulus of the hydrogel with a high proportion of fluorine-containing nanofibers is significantly higher than that of the hydrogel with a low proportion of fluorine-containing nanofibers, indicating that fluorine-containing nanofibers can enhance the mechanical strength of the hydrogel material.

[0080] The hydrogels in Example 6 and Comparative Example 2 were subjected to Li + Adsorption capacity test characterization, Figure 8 The adsorption patterns of nanofiber hydrogels prepared by different modification methods are shown in Figure 2. Figure 8 It can be seen that the adsorption capacity of fluorine-containing nanofiber hydrogel is significantly stronger than that of carboxyl-containing nanofiber TOChNs hydrogel, indicating that fluorine-modified nanofibers have a better adsorption capacity for Li +It has strong adsorption capacity and superiority.

[0081] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a fluorine-containing nanofiber dispersion, characterized in that: include, The fragmented cellulose or chitin is pre-cooled under low temperature conditions; Adding fluorinated acid anhydride to the cellulose or chitin, allowing the mixture to react fully, adding alkali for repeated washing and centrifugation to remove unreacted acid anhydride, thereby obtaining a fluorinated cellulose or fluorinated chitin precipitate; Taking the fluorinated cellulose or fluorinated chitin precipitate, dispersing it in a water system and dialyzing it to obtain a fluorinated cellulose or fluorinated chitin aqueous suspension; The fluorinated cellulose or fluorinated chitin aqueous suspension is taken, the pH is adjusted to neutral or weakly alkaline, and then mechanically dispersed, ultrasonically treated, and centrifuged to remove precipitation to obtain a fluorinated cellulose nanofiber or fluorinated chitin nanofiber dispersion.

2. The method for preparing a fluorine-containing nanofiber dispersion according to claim 1, wherein: The cellulose is one or more of cotton cellulose, hemp cellulose, bamboo cellulose, wood cellulose, grass cellulose, and microcrystalline cellulose; The chitin is one or more of crab shell chitin, shrimp shell chitin, and squid cartilage chitin; The low-temperature pre-cooling treatment is performed using liquid nitrogen or an ice bath.

3. The method for preparing a fluorine-containing nanofiber dispersion according to claim 1, wherein: The fluorine-containing acid anhydride is one or more of trifluoroacetic anhydride, tetrafluorosuccinic anhydride, pentafluoropropionic anhydride, hexafluoroglutaric anhydride, heptafluorobutyric anhydride, trifluoromethanesulfonic anhydride, trifluoromethanesulfonic anhydride, perfluorobutylsulfonic anhydride, and nonafluorobutylsulfonic anhydride.

4. The method for preparing a fluorine-containing nanofiber dispersion according to claim 3, wherein: The mass ratio of the cellulose or chitin to the fluorine-containing acid anhydride is 3:20-40.

5. The method for preparing a fluorine-containing nanofiber dispersion according to claim 3 or 4, wherein: The reaction is fully carried out at a temperature of 65 to 100° C., a time of 1 to 6 hours, and a stirring speed of 100 to 1000 r / min.

6. The method for preparing a fluorine-containing nanofiber dispersion according to claim 5, wherein: The base is a hydroxide or a carbonate.

7. The method for preparing a fluorine-containing nanofiber dispersion according to claim 1, wherein: The dialysis uses an 8-14 kDa dialysis bag, and the dialysis time is 1-2 days.

8. The method for preparing a fluorine-containing nanofiber dispersion according to claim 1, wherein: The mechanical dispersion has a dispersion time of 5 to 10 minutes; The ultrasonic treatment time is 30 to 60 minutes; The centrifuge speed is 10000 r / min and the centrifugation time is 3 to 5 minutes.

9. Use of the fluorine-containing nanofiber dispersion obtained by the preparation method according to any one of claims 1 to 8 in nanofiber films and gel adsorbent materials.

10. A method for preparing fluorine-containing nanofiber hydrogel, characterized by: include, The fluorine-containing nanofiber dispersion obtained by the preparation method according to any one of claims 1 to 8 is fully mixed with gelatin and a cross-linking agent, and the mixture is frozen to form a fluorine-containing nanofiber hydrogel; The mass ratio of the fluorine-containing nanofiber dispersion to gelatin is 1:1-3.

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