A COF aerogel composite adsorbent material for PFAS treatment, its preparation method and application

Abstract

This invention discloses a COF aerogel composite material for PFAS treatment, its preparation method, and its applications, relating to the field of pollutant adsorption. The composite material comprises the following components: 68.18%–70% COF material, 22.73%–90.91% CS solution, and 9.09% TP solution. The COF material includes 0.0764 mmol (30 mg) ETTA, 0.1528 mmol of a side-functional monomer, and 3 mL of o-dichlorobenzene / n-butanol solvent. The volume ratio of o-dichlorobenzene to n-butanol in the o-dichlorobenzene / n-butanol solvent is 1:1. The side-functional monomer includes 0.025 mmol TFTDA / 0.127 mmol BFBlM, named COF-F1N5. This invention provides a series of synthesized COF / aerogels that are ultralight, pressure-resistant, stable, and have low specific surface area loss, overcoming the application limitations of COF powder, are easily recyclable, and exhibit good adsorption performance for PFAS.

Description

Technical Field

[0001] This invention relates to the field of pollutant adsorption, and in particular to a COF aerogel composite adsorbent material for PFAS treatment, its preparation method, and its application. Background Technology

[0002] Per- or polyfluoroalkyl substances (PFAS) are a class of synthetically produced compounds characterized by the replacement of all or part of the hydrogen atoms directly bonded to carbon atoms in the carbon chain with fluorine atoms. They are used in a variety of consumer and industrial products. Due to their carcinogenic and biotoxic properties, as well as their persistence and bioaccumulation in the environment, they are widely exposed in environmental media, especially in water and food, posing a serious threat to human health.

[0003] Covalent organic frameworks (COFs) are porous organic nanomaterials widely used for the adsorption and treatment of PFAS pollutants due to their ordered porosity, stability, and customizable functions. However, in practical applications, COF powders are often directly packed into columns. The powder form is prone to agglomeration in real-world applications, making it difficult to disperse in water, resulting in low flux, difficulty in recovery, and environmental pollution, which severely limits its application in water. Especially in the context of PFAS adsorption and treatment, the hydrophobicity of COFs makes uniform dispersion in water difficult, leading to aggregation on the liquid surface and poor permeability. This characteristic severely restricts its application in water treatment, pretreatment extraction, and other fields. Combining COFs with other functional materials to construct hybrid material systems can adjust the hydrophobicity of COFs, improve flux, and overcome the shortcomings of COFs from the laboratory to practical application.

[0004] Although some COF aerogel materials have been reported in studies, most are synthesized in situ, which cannot guarantee the functionality of COF in composite materials. Furthermore, there are no reports on the application of COF aerogels in PFAS treatment.

[0005] Furthermore, all reported COF aerogels currently available are monoporous COFs. Heteroporous COFs, also known as hierarchical porous COF nanomaterials, have found wide application in catalysis, energy storage, and environmental fields due to their unique two or more ordered porous network structures. The ordered pore size of hierarchical porous structures provides a potential adsorption platform for PFAS of different chain lengths. However, heteroporous COFs also face the challenge of widespread COF application. Therefore, there is an urgent need to develop a COF aerogel composite material for PFAS treatment to overcome the inherent limitations of COFs in practical applications and expand their application range. This can be achieved by utilizing the macroporous environment provided by the aerogel and the mesoporous and microporous environments of the heteroporous COF material to jointly construct a hierarchical porous structure.

[0006] However, constructing COF aerogels by co-constructing heteroporous COF and aerogel presents significant challenges and has not been reported. Therefore, this patent describes a hierarchical porous COF / aerogel composite material for the simultaneous adsorption and removal of both long-chain and short-chain PFAS. Summary of the Invention

[0007] To address the aforementioned issues, this application proposes a COF aerogel composite adsorbent material for PFAS treatment comprising the following components: COF material, CS solution, and TP solution;

[0008] The COF material comprises 0.0382-0.0764 mmol of ETTA, 15-30 mg of ETTA, 0.0764-0.1528 mmol of a side-functionalized monomer, and 1.5-3 mL of o-dichlorobenzene / n-butanol solvent;

[0009] The volume ratio of o-dichlorobenzene to n-butanol in the o-dichlorobenzene / n-butanol solvent is 1:1;

[0010] The side-functional monomers include 0.0125-0.025 mmol TFTDA and 0.0635-0.127 mmol BFBlM, named COF-F1N5.

[0011] A method for preparing COF aerogel composite material for PFAS treatment, comprising:

[0012] S1. Synthesis of heteroporous fluorine-doped cation COF;

[0013] S2. Synthesis of COF / chitosan aerogel composite material based on heteroporous fluorine-doped cationic COF.

[0014] Preferably, the specific steps of S1 are as follows:

[0015] S101. Mix ETTA, side-functionalized monomer, and o-dichlorobenzene / n-butanol solvent to obtain a primary mixed solution;

[0016] S102. Add acetic acid as a catalyst to the primary mixed solution and mix to obtain a secondary mixed solution;

[0017] S103. Degas and seal the secondary mixed solution. After the secondary mixed solution returns to room temperature, transfer it to a muffle furnace for reaction to obtain the product solid.

[0018] S104. Wash and filter the product solids to obtain the initial material;

[0019] S105. The initial material is vacuum dried overnight to obtain COF nanomaterials, which are then ground and sieved to obtain COF powder.

[0020] Preferably, the specific steps of S2 are as follows:

[0021] S201. Dissolve chitosan CS in an aqueous acetic acid solution and shake to form a uniform and transparent CS solution;

[0022] S202. Add COF powder to CS solution, shake and sonicate to disperse evenly to obtain a dispersion solution;

[0023] S203. Add TP solution to the dispersion solution, shake, and then sonicate to form a hydrogel;

[0024] S204 hydrogels form highly cross-linked and stable hydrogels when left undisturbed at room temperature.

[0025] S205. A highly cross-linked and stable hydrogel is frozen and vacuum dried to obtain a COF aerogel composite adsorbent material.

[0026] Preferably, the acetic acid content in S102 is 6-10 mol, and the volume is 0.3-0.6 mL.

[0027] Preferably, the acetic acid aqueous solution in S201 is 800-1000 μL, with a concentration of 0.2-0.5 mol / L;

[0028] S203 followed by 200-400 μL of TP solution, 10-15 mg / L.

[0029] Preferably, the mixture in S101 is subjected to ultrasonic treatment for 15-30 minutes;

[0030] The mixture in S102 is subjected to ultrasonic treatment for 10-30 minutes;

[0031] In S103, the secondary mixed solution is degassed and sealed using liquid nitrogen through three freezing-pumping-thawing cycles.

[0032] The temperature of the muffle furnace is 120-140℃, and the reaction time is 72-96 hours.

[0033] The solid product in S104 was thoroughly washed and filtered 5 times with ultra-dry tetrahydrofuran, and then thoroughly washed and filtered 3 times with anhydrous ethanol.

[0034] COF nanomaterials were obtained by vacuum drying the initial material in S105 overnight at 80-120℃.

[0035] Preferably, the oscillation time is 10-20 seconds within the 201 cycle.

[0036] In S202, 10-20 seconds, and then uniformly dispersed by ultrasonic treatment for 10-15 minutes;

[0037] S204 should be left to stand for 12-18 hours;

[0038] Place the S205 hydrogel in a -80 degree freezer for at least 12 hours;

[0039] COF aerogel composite adsorbent material was obtained by vacuum freeze-drying of hydrogel for 36 hours.

[0040] Preferably, the ratio of COF to CS in S202 is 1:3-4:1.

[0041] The COF aerogel composite material prepared by the method is used for the adsorption of PFAS.

[0042] In summary, the present invention provides a COF aerogel composite adsorbent material for PFAS treatment, its preparation method, and its application. Compared with traditional technologies, the series of COF / aerogels synthesized in this invention exhibit ultralight weight (26 mg / cm³). 3 It exhibits excellent pressure resistance (able to withstand 100g of pressure while maintaining its original structure), good stability (maintaining its structure in water for 30 days), and good adsorption performance for PFAS, especially COF / CS-4, which demonstrates rapid adsorption kinetics. This is particularly evident in the rapid treatment of PFAS in water, especially in co-dissolved systems of long-chain and short-chain PFAS, where the adsorption of short-chain PFAS is enhanced. Compared to commercial adsorbents, COF aerogel significantly enhances the adsorption and treatment of PFAS in water while maintaining stability in the aquatic environment.

[0043] The technical method of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0044] Figure 1 The images show the morphology of the five aerogels in the examples. Figure 1 Image a shows the morphology of CS aerogel. Figure 1 Figure b shows the morphology of COF / CS-1 aerogel. Figure 1 In the middle, c is the morphology diagram of COF / CS-2 aerogel. Figure 1 In the middle, d represents the morphology of COF / CS-3 aerogel. Figure 1 In the middle, e represents the morphology of COF / CS-4 aerogel;

[0045] Figure 2 This is a diagram showing the state of the aerogel placed on the fine hairs of foxtail grass in the example. Figure 2 In the diagram, a represents the state of CS aerogel. Figure 2 b is a state diagram of COF / CS-4 aerogel;

[0046] Figure 3 The graph shows the changes of the five aerogels placed in ultrapure water over time in the example. Figure 3 Figure a shows the five aerogel states over 24 hours. Figure 3 Figure b shows the five aerogel states after 48 hours. Figure 3Figure c shows the five aerogel states after 72 hours. Figure 3 In the diagram, d represents the five aerogel states after 96 hours. Figure 3 The image in section e shows the five aerogel states over 15 days. Figure 3 The diagram in Figure f shows the five aerogel states over 30 days.

[0047] Figure 4 This is a diagram showing that COF / CS-4 can withstand a weight of 100g in the example.

[0048] Figure 5 This is a diagram illustrating the recovery process of COF / CS-4 under different pressure ratios in the examples.

[0049] Figure 6 The figures shown are isothermal adsorption and nonlinear fitting diagrams for five types of aerogels in the examples. Figure 6 Figure 'a' shows the isothermal adsorption and nonlinear fitting of PFOA by five aerogels. Figure 6 In the middle b, there is the isothermal adsorption and nonlinear fitting of five aerogels on GenX;

[0050] Figure 7 This is a schematic diagram illustrating the PFOA removal rates of different COF aerogels in the examples;

[0051] Figure 8 This is a schematic diagram illustrating the Gen X removal rates of different COF aerogels in the examples;

[0052] Figure 9 This example compares COF / CS-4 with commercial adsorbents in isothermal adsorption experiments. Figure 9 In Figure 'a', the isothermal adsorption experiment comparison of PFOA with COF / CS-4 and a commercial adsorbent is shown. Figure 9 In Figure b, the isothermal adsorption experiment comparison between GenX's COF / CS-4 and commercial adsorbents is shown.

[0053] Figure 10 This example compares COF / CS-4 with commercial adsorbents in adsorption kinetics experiments. Figure 10 In Figure 'a', the adsorption kinetics of PFOA with COF / CS-4 are compared with those of commercial adsorbents. Figure 10 In Figure b, the adsorption kinetics of GenX's COF / CS-4 are compared with those of commercial adsorbents. Detailed Implementation

[0054] The technical method of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application.

[0055] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0056] Techniques, systems, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the instruction manual.

[0057] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0058] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0059] By enhancing the dispersibility and mechanical stability of COF in aqueous media through the three-dimensional network structure of aerogel, the shortcomings of COF in practical applications can be compensated. By integrating the biocompatibility of chitosan, the high specific surface area of ​​COF, and the hierarchical porous structure of aerogel, this study aims to overcome the technical bottlenecks of traditional materials such as low adsorption capacity, slow adsorption rate, and high environmental risk for PFAS, and provide a new strategy for the green and efficient removal of PFAS in complex water systems.

[0060] A method for preparing COF aerogel composite material for PFAS treatment, comprising:

[0061] S1. Synthesis of heteroporous fluorine-doped cation COF, the specific steps are as follows:

[0062] 0.0764 mmol, 30 mg ETTA was added to a glass tube, followed by 0.1528 mmol of the side-functionalized monomer (0.025 mmol TFTDA / 0.127 mmol BFBlM, named COF-F1N5). Then, 3 mL of o-dichlorobenzene / n-butanol solvent (1:1, v / v) was added, and the mixture was sonicated for 15 min to ensure thorough mixing. Next, 6 mol, 0.3 mL of acetic acid was added to each tube as a catalyst, and the mixture was immediately sonicated for 10 min. The mixture was then rapidly degassed with liquid nitrogen through three freeze-pump-thaw cycles and sealed. After the system returned to room temperature, it was transferred to a muffle furnace at 120 °C and reacted for 72 hours. After the reaction, the product was thoroughly washed with ultra-dry tetrahydrofuran and filtered five times, then thoroughly washed with anhydrous ethanol and filtered three times. Finally, the washed material was vacuum-dried overnight at 80 °C to obtain COF nanomaterials, which were then ground and sieved to obtain COF powder.

[0063] Table 1 shows different COF and CS ratios according to

[0064]

[0065] S2. Based on heteroporous fluorine-doped cationic COF, COF / chitosan aerogel composite material was synthesized. Different COF and CS ratios were shown in Table 1. The specific steps are shown in the following examples.

[0066] Example 1

[0067] First, 20 mg of chitosan (CS) was dissolved in an aqueous acetic acid solution (800 μL, 0.2 mol / L), and shaken for 10 s to form a homogeneous and transparent CS solution. Then, 200 μL of TP solution (10 mg / L) was added, shaken for 10 s, and then rapidly transferred and sonicated until a hydrogel was formed. Figure 1 As shown in 'a'.

[0068] Example 2

[0069] First, 15 mg of chitosan (CS) was dissolved in an aqueous acetic acid solution (800 μL, 0.2 mol / L) and shaken for 10 s to form a homogeneous and transparent CS solution. Then, 5 mg of powdered COF material was added to the CS solution, shaken for 10 s, and then uniformly dispersed by ultrasonication for 10 minutes. Subsequently, 200 μL of TP solution (10 mg / L) was added, shaken for 10 s, and then rapidly transferred to ultrasonication until a hydrogel was formed. The hydrogel was then left to stand undisturbed at room temperature for 12 hours to form a highly cross-linked and stable hydrogel. The hydrogel was then frozen at -80°C for at least 12 hours. Finally, the frozen COF aerogel was freeze-dried under vacuum for 36 hours to obtain the COF aerogel composite adsorbent material, as shown below. Figure 1 As shown in b in the figure.

[0070] Example 3

[0071] First, 10 mg of chitosan (CS) was dissolved in an aqueous acetic acid solution (800 μL, 0.2 mol / L) and shaken for 10 s to form a homogeneous and transparent CS solution. Then, 10 mg of powdered COF material was added to the CS solution, shaken for 10 s, and then uniformly dispersed by ultrasonication for 10 minutes. Subsequently, 200 μL of TP solution (10 mg / L) was added, shaken for 10 s, and then rapidly transferred to ultrasonication until a hydrogel was formed. The hydrogel was then left to stand undisturbed at room temperature for 12 hours to form a highly cross-linked and stable hydrogel. The hydrogel was then frozen at -80°C for at least 12 hours. Finally, the frozen COF aerogel was freeze-dried under vacuum for 36 hours to obtain the COF aerogel composite adsorbent material, as shown below. Figure 1 As shown in c in the figure.

[0072] Example 4

[0073] First, 6.67 mg of chitosan (CS) was dissolved in an aqueous acetic acid solution (800 μL, 0.2 mol / L), and shaken for 10 s to form a homogeneous and transparent CS solution. Then, 13.33 mg of powdered COF material was added to the CS solution, shaken for 10 s, and then uniformly dispersed by ultrasonication for 10 minutes. Subsequently, 200 μL of TP solution (10 mg / L) was added, shaken for 10 s, and then rapidly transferred to ultrasonication until a hydrogel was formed. The hydrogel was then allowed to stand undisturbed at room temperature for 12 hours to form a highly cross-linked and stable hydrogel. The hydrogel was then frozen at -80°C for at least 12 hours. Finally, the frozen COF aerogel was freeze-dried under vacuum for 36 hours to obtain the COF aerogel composite adsorbent material, as shown below. Figure 1 As shown in d.

[0074] Example 5

[0075] First, 5 mg of chitosan (CS) was dissolved in an aqueous acetic acid solution (800 μL, 0.2 mol / L) and shaken for 10 s to form a homogeneous and transparent CS solution. Then, 15 mg of powdered COF material was added to the CS solution, shaken for 10 s, and then uniformly dispersed by ultrasonication for 10 minutes. Subsequently, 200 μL of TP solution (10 mg / L) was added, shaken for 10 s, and then rapidly transferred to ultrasonication until a hydrogel was formed. The hydrogel was then left to stand undisturbed at room temperature for 12 hours to form a highly cross-linked and stable hydrogel. The hydrogel was then frozen at -80°C for at least 12 hours. Finally, the frozen COF aerogel was freeze-dried under vacuum for 36 hours to obtain the COF aerogel composite adsorbent material, such as... Figure 1 As shown in e.

[0076] The five forms of aerogel are as follows Figure 1 As shown: CS aerogel is white, and the color of COF / CS aerogel gradually darkens as the proportion of COF incorporation gradually increases.

[0077] COF / CS aerogels have a low density (22.27–26 mg / cm³). 3 It has the characteristics of being ultra-lightweight, such as... Figure 2 As shown:

[0078] like Figure 3 As shown, a series of synthesized aerogels can maintain their original shape after 30 days when placed in ultrapure water, and float on the surface of the liquid due to their low density.

[0079] like Figure 4-5 As shown, it has certain pressure resistance and self-healing properties.

[0080] The synthesized series of COF / aerogels are ultralight, pressure resistant, stable, and have low specific surface area loss. They exhibit good adsorption performance for PFAS, especially COF / CS-4, which has fast adsorption kinetics and has certain application potential for the rapid treatment of PFAS in water.

[0081] Adsorption performance of PFAS

[0082] The adsorption performance of five COF aerogels was evaluated using isothermal adsorption experiments and adsorption kinetic experiments. Adsorption capacity and adsorption rate were calculated using the following formulas:

[0083]

[0084] C0 and C e (mg / L) represent the initial and equilibrium concentrations of PFAS, respectively. t The PFAS concentration at time t represents the adsorbent concentration. m (mg) and V (mL) represent the adsorbent mass and solution volume, respectively. Furthermore, the Langmuir and Freundlich adsorption isotherm models were used to fit the adsorption process of the two PFAS on the heteroporous COF to describe the adsorption process of the COF material in this study.

[0085] The equation for the Langmuir adsorption isotherm is as follows:

[0086]

[0087] The Freundlich adsorption isotherm equation is as follows:

[0088]

[0089] q m (mg / g) represents the maximum adsorption capacity, K L K is Langmuir's constant. F C is the Freundlich constant. e (mg / L) represents the concentration of PFAS at adsorption equilibrium.

[0090] First, such as Figure 6 As shown, CS aerogel without COF loading also exhibits a high adsorption capacity for PFOA. With increasing COF loading, q e With further increases, COF / CS-2 reached its maximum adsorption capacity; subsequently, it tended to stabilize.

[0091] The isothermal adsorption results and nonlinear fitting results of five COF aerogels for GenX (perfluoroalkyl substances) are as follows: Figure 7As shown, similar to PFOA, CS aerogel without COF loading also exhibits a certain adsorption capacity for GenX, but it is relatively low. With increasing COF loading, qe increases significantly, and COF / CS-2 also reaches its maximum adsorption capacity; subsequently, it tends to stabilize. The fitting results indicate that the Langmuir model can better describe the adsorption process.

[0092] Adsorption kinetics test method: 30 mL of PFOA or Gen X (1 mg / L) aqueous solution was added to the bottle. Then, COF aerogel material was added and thoroughly mixed. Subsequently, the mixture was treated at room temperature for different time intervals (2 min, 5 min, 10 min, 15 min, 30 min, 1 h, 2 h) on a shaker at 250 rpm. All sample mixtures were filtered through a 0.2 μm membrane filter, and the filtrate was analyzed using UHPLC-MS / MS to determine the remaining PFOA and Gen X content. All batch experiments were repeated three times. The kinetic adsorption process was fitted using removal rate, a pseudo-first-order kinetic model, and a pseudo-second-order kinetic model to describe the adsorption process of the COF material in this study. The calculation formulas for the pseudo-first-order and pseudo-second-order kinetic models are shown below:

[0093] In(q e -q t ) = Inq e -k1t;

[0094]

[0095] q t (mg / g) and q e (mg / g) represents the adsorption loading of the adsorbent at time t (min) and equilibrium, respectively. Furthermore, the pseudo-first-order rate constant and pseudo-second-order rate constant are represented by k1 (min). -1 ) and k2 (g mg -1 min -1 )express.

[0096] according to Figure 7 It can be seen that although CS aerogel has a good adsorption capacity, pure CS aerogel has poor kinetics, reaching a removal rate of nearly 100% within 120 min. With the incorporation of COF, the adsorption kinetics of COF / CS aerogel improves almost linearly, especially COF / CS-4, which reaches a removal rate of over 90% within 10 min.

[0097] like Figure 8For short-chain GenX, the PFAS kinetics of pure CS aerogel were poor for ultra-short chains. However, with the incorporation of COF, the adsorption kinetics of COF / CS aerogel also showed a similar linear improvement, especially COF / CS-4, which achieved a removal rate of over 80% at 2 min and over 90% at 5 min.

[0098] Compared with commercial adsorbents:

[0099] Activated carbon and β-cyclodextrin are among the most common adsorbents. The adsorption performance of COF / CS-4 was compared with other commercial adsorbents. Isothermal adsorption experiments and adsorption kinetics were conducted under the same conditions, and the results are as follows: Figure 9-10 As shown, compared to commercial adsorbents activated carbon and β-cyclodextrin, the adsorption loading capacity of COF / CS-4 aerogel is increased by 6-7 times, and the adsorption kinetics are shortened from 120 minutes to less than 15 minutes to reach adsorption equilibrium.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical methods of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical methods of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical methods to deviate from the spirit and scope of the technical methods of the present invention.

Claims

1. A COF aerogel composite material for PFAS treatment, characterized in that, include: COF materials; Chitosan CS; The mass ratio of the COF material to chitosan CS is 1:3-4:1; Trialdehyde-based phloroglucinol TP solution; The COF material comprises 0.0382-0.0764 mmol of tetra-(4-aminophenyl)ethylene ETTA, 15-30 mg, 0.0764-0.1528 mmol of the side-functionalized monomer, and 1.5-3 mL of o-dichlorobenzene / n-butanol solvent; The volume ratio of o-dichlorobenzene to n-butanol in the o-dichlorobenzene / n-butanol solvent is 1:1; The side-functional monomers include 0.0125-0.025 mmol 2',3',5',6'-tetrafluoro-[1,1':4',1''-terphenyl]-4,4''-diformaldehyde TFTDA; and 0.0635-0.127 mmol 4,7-bis(4-formylphenyl)-1,3-dimethyl-1H-benzo[d]imidazole-3-bromium bromide BFBlM, named COF-F1N5.

2. A method for preparing a COF aerogel composite material for PFAS treatment, for preparing the COF aerogel composite material for PFAS treatment as described in claim 1, characterized in that, include: S1. Synthesis of heteroporous fluorine-doped cation COF; S2. Synthesis of COF / chitosan aerogel composite material based on heteroporous fluorine-doped cationic COF.

3. The method for preparing a COF aerogel composite material for PFAS treatment according to claim 2, characterized in that, The specific steps of S1 are as follows: S101. Mix ETTA, side-functionalized monomer, and o-dichlorobenzene / n-butanol solvent to obtain a primary mixed solution; S102. Add acetic acid as a catalyst to the primary mixed solution and mix to obtain a secondary mixed solution; S103. Degas and seal the secondary mixed solution. After the secondary mixed solution returns to room temperature, transfer it to a muffle furnace for reaction to obtain the product solid. S104. Wash and filter the product solids to obtain the initial material; S105. The initial material is vacuum dried overnight to obtain COF nanomaterials, which are then ground and sieved to obtain COF powder.

4. The method for preparing a COF aerogel composite material for PFAS treatment according to claim 3, characterized in that, The specific steps of S2 are as follows: S201. Dissolve chitosan CS in an aqueous acetic acid solution and shake to form a uniform and transparent CS solution; S202. Add COF powder to CS solution, shake and sonicate to disperse evenly to obtain a dispersion solution; S203. Add TP solution to the dispersion solution, shake, and then sonicate to form a hydrogel; S204 hydrogels form highly cross-linked and stable hydrogels when left undisturbed at room temperature. S205. A highly cross-linked and stable hydrogel is frozen and vacuum dried to obtain a COF aerogel composite adsorbent material.

5. The method for preparing a COF aerogel composite material for PFAS treatment according to claim 3, characterized in that, The acetic acid content in S102 is 6-10 mol, or 0.3-0.6 mL.

6. The method for preparing a COF aerogel composite material for PFAS treatment according to claim 4, characterized in that, S201 contains 800-1000 μL of acetic acid aqueous solution, 0.2-0.5 mol / L; S203 followed by 200-400 μL of TP solution, 10-15 mg / L.

7. The method for preparing a COF aerogel composite material for PFAS treatment according to claim 3, characterized in that, The mixture in S101 is subjected to ultrasonic treatment for 15-30 min; The mixture in S102 is subjected to ultrasonic treatment for 10-30 min; In S103, the secondary mixed solution is degassed and sealed using liquid nitrogen through three freezing-pumping-thawing cycles. The muffle furnace temperature is 120-140 °C, and the reaction time is 72-96 hours; The solid product in S104 was thoroughly washed and filtered 5 times with ultra-dry tetrahydrofuran, and then thoroughly washed and filtered 3 times with anhydrous ethanol. COF nanomaterials were obtained by vacuum drying the initial material in S105 overnight at 80-120 °C.

8. The method for preparing a COF aerogel composite material for PFAS treatment according to claim 4, characterized in that, Oscillation within 201 for 10-20 seconds; Vibrate in S202 for 10-20 seconds, and then disperse evenly by ultrasonic treatment for 10-15 minutes; S204 should be left to stand for 12-18 hours; Place the S205 hydrogel in a -80°C freezer for 12-18 hours; COF aerogel composite adsorbent material was obtained by vacuum freeze-drying of aerogel for 36 hours.

9. The method for preparing a COF aerogel composite material for PFAS treatment according to claim 4, characterized in that, The ratio of COF to CS in S202 is 1:3-4:

1.

10. The application of the COF aerogel composite material prepared by the preparation method according to any one of claims 1 to 9, characterized in that, The COF aerogel composite material is used for the adsorption of short-chain PFAS in a co-solution system of long-chain and short-chain PFAS.

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