A hyperbranched polyamidoamine-chitosan aerogel and a preparation method thereof

Abstract

The application discloses a kind of hyperbranched polyamidoamine-chitosan aerogel and preparation method thereof, belong to adsorption material field.The preparation method includes: (1) synthesis hyperbranched polyamidoamine;(2) chitosan is dissolved in dilute acetic acid solution, then hyperbranched polyamidoamine is added in above-mentioned solution and is stirred to form clear liquid, by adding crosslinking agent, form hyperbranched polyamidoamine-chitosan gel;(3) hyperbranched polyamidoamine-chitosan gel is frozen and dried to obtain hyperbranched polyamidoamine-chitosan aerogel.Preparation method is simple, and preparation cost is low, in addition, hyperbranched polyamidoamine-chitosan aerogel obtained by the method of the application has three-dimensional network structure, is favorable for hexavalent chromium ion to enter the inside of the material, improves the adsorption performance of hyperbranched polyamidoamine-chitosan aerogel, and has good application prospect in the technical field such as heavy metal ion treatment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of adsorption materials, and relates to a hyperbranched polyamidoamine-chitosan aerogel and a preparation method thereof. BACKGROUND

[0002] Heavy metal pollution has a serious impact on human life. Among common heavy metal ions, chromium ions attract people's attention due to their great toxicity, which mainly comes from the leather tanning, electroplating and pigment manufacturing industries. In nature, chromium ions mainly exist in the form of trivalent chromium and hexavalent chromium, and the toxicity of hexavalent chromium is much greater than that of trivalent chromium. Hexavalent chromium can cause chromosomal aberrations, and long-term exposure to hexavalent chromium can cause nausea, upper abdominal pain and bleeding, and even lung cancer and gastrointestinal cancer (Polyhedron 15 (1995) 3667-3689). It has been reported that the concentration of hexavalent chromium in drinking water in China is less than 0.05 mg / L, and the concentration of hexavalent chromium in industrial wastewater is less than 0.5 mg / L (Chem. Eng. J. 408 (2021) 127327, ACS Appl. Mater. Interfaces 9 (2017) 15525-15532). Therefore, it is very important to find an ideal adsorbent material to remove hexavalent chromium ions in industrial wastewater to reduce its threat to humans.

[0003] Common methods for removing hexavalent chromium ions include ion exchange method, electrochemical reduction method, chemical precipitation method, membrane filtration method and adsorption method. Among them, the ion exchange resin used in the ion exchange method is easily contaminated by organic matter; the electrochemical reduction method and the membrane filtration method have high use cost; the chemical precipitation method is easy to cause secondary pollution. Compared with the above, the adsorption method is valued by people due to its high removal efficiency, low preparation cost and no secondary pollution.

[0004] Chitosan is abundant in nature, and its raw material is easy to obtain. It has good compatibility with organisms and can be degraded, and is a natural polymer material with great development prospects (Progress in Polymer Science 31 (7) (2006) 603-632). In addition, chitosan molecules contain a large number of amine groups and hydroxyl groups, which makes it easy to adsorb heavy metal ions. Therefore, chitosan is an ideal adsorbent material. For common chitosan powder, chitosan aerogel has more advantages, such as easy recovery and high porosity. However, due to the relatively small number of amine groups in chitosan aerogel, its adsorption efficiency for hexavalent chromium is not very high. This shortcoming limits the application range of chitosan aerogel adsorbent. In order to improve the use range of chitosan aerogel, it is a good strategy to introduce a large number of amine groups into chitosan to form chitosan aerogel derivatives.

[0005] Hyperbranched polyamidoamine has the advantages of low viscosity, chain not easy to entangle, good solubility, containing a large number of amine functional groups and three-dimensional network structure, etc., and is valued and favored by the majority of researchers, and is regarded as an important direction of the development of polymer science in the 21st century. The patent aims to provide a preparation method of hyperbranched polyamidoamine-chitosan aerogel, and preliminarily explore the adsorption capacity of the material for hexavalent chromium. SUMMARY

[0006] The present application aims to provide a kind of hyperbranched polyamidoamine-chitosan aerogel and preparation method thereof.The present application uses hyperbranched polyamidoamine and chitosan as raw material, uses the coordination strategy of dissolution and crosslinking to prepare hyperbranched polyamidoamine-chitosan aerogel.The present application is simple to prepare, low in cost, and environmentally friendly material, and has good application prospect in the field of heavy metal ion adsorption.

[0007] The technical scheme of the present application is as follows:

[0008] A kind of hyperbranched polyamidoamine-chitosan aerogel and preparation method thereof, comprising the following steps:

[0009] (1) diethylenetriamine and dimethyl maleate are used as raw materials, stirred under ice bath condition for 4-6h, then warmed to 90-110 DEG C, and reacted for 7-10h in open condition to obtain viscous yellow liquid, i.e.

[0010] (2) chitosan is dissolved in dilute acetic acid solution, then hyperbranched polyamidoamine obtained in step (1) is added into the above solution, stirred for 2-4h to obtain transparent solution, then crosslinking agent is slowly added into the transparent solution while stirring to obtain hyperbranched polyamidoamine-chitosan gel, and then solidified at room temperature for 4-6h.

[0011] (3) hyperbranched polyamidoamine-chitosan gel obtained in step (2) is washed with water for multiple times, and hyperbranched polyamidoamine-chitosan aerogel is obtained after freeze-drying.

[0012] Further, in the above technical scheme, in step (1), the molar ratio of diethylenetriamine to dimethyl maleate is 1.5:1-2.5:1, preferably 2:1.

[0013] Further, in the above technical scheme, in step (2), the mass ratio of chitosan to dilute acetic acid solution is 1:40-1:100, preferably 1:50.

[0014] Further, in the above technical scheme, in step (2), the mass concentration of the dilute acetic acid solution is 1-5%, preferably 2%.

[0015] Further, in the technical solution above, in step (2), the mass ratio of the hyperbranched polyamidoamine to the dilute acetic acid solution is 3:100-4:100.

[0016] Further, in the technical solution above, in step (2), the crosslinking agent is preferably epoxy chloropropane or glutaraldehyde, and glutaraldehyde is preferred.

[0017] Further, in the technical solution above, in step (2), the mass ratio of the crosslinking agent to the dilute acetic acid solution is 1:25-1:100.

[0018] Further, in the technical solution above, in step (3), the water used for washing is deionized water or tap water, and deionized water is preferred.

[0019] Further, in the technical solution above, in step (3), the freeze-drying temperature is less than -60 DEG C, and the freeze-drying time is greater than or equal to 48 h. Preferably, the freeze-drying temperature is -70 DEG C, and the freeze-drying time is 48 h.

[0020] The present application has the following advantages:

[0021] (1) One of the raw materials used in the present application is chitosan, which is inexpensive, easy to obtain, green and non-toxic. In addition, the preparation process of the hyperbranched polyamidoamine-chitosan aerogel is relatively simple, and the production cost is low.

[0022] (2) The hyperbranched polyamidoamine-chitosan aerogel has a three-dimensional network structure and contains a large number of amine groups, and has good heavy metal ion adsorption capacity.

[0023] (3) The prepared hyperbranched polyamidoamine-chitosan aerogel has the advantages of structural stability and easy recovery, and is a novel heavy metal ion adsorbent that has never been reported. BRIEF DESCRIPTION OF DRAWINGS

[0024] The embodiments of the present application will be described in detail with reference to the accompanying drawings, in which

[0025] Figure 1 : The infrared spectrum of the hyperbranched polyamidoamine-chitosan aerogel prepared in Example 4.

[0026] Figure 2 : The scanning electron microscope image of the hyperbranched polyamidoamine-chitosan aerogel prepared in Example 4.

[0027] Figure 3 : The adsorption capacity graph of the hyperbranched polyamidoamine-chitosan aerogel prepared in Example 4 for hexavalent chromium.

[0028] Figure 4Cycling of the hyperbranched polyamidoamine-chitosan aerogel prepared in Example 4. DETAILED DESCRIPTION

[0029] The application will be further described in conjunction with the following examples, but the embodiments of the application are not limited to them. The experimental methods described in the following examples are conventional methods, and the reagents and materials described are commercially available unless otherwise specified.

[0030] Example 1

[0031] Preparation of a hyperbranched polyamidoamine-chitosan aerogel:

[0032] (1) Diethylenetriamine (41.3 g, 0.4 mol) and dimethyl maleate (28.8 g, 0.2 mol) were added to a 250 mL four-necked flask and stirred for 5 h in an ice bath, then warmed to 100 °C and reacted for 8 h with open mouth, to obtain a viscous yellow liquid, i.e. hyperbranched polyamidoamine.

[0033] (2) 1 g of chitosan was dissolved in a 2% acetic acid solution (50 g), and then the hyperbranched polyamidoamine (1.5 g) obtained in step (1) was added to the above solution, stirred for 3 h to obtain a transparent solution, and then 1 g of glutaraldehyde was slowly dropped into the transparent solution while stirring to obtain a hyperbranched polyamidoamine-chitosan gel, which was then solidified at room temperature for 5 h.

[0034] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) was washed with deionized water for several times, and then freeze-dried at -70 °C for 48 h to obtain a hyperbranched polyamidoamine-chitosan aerogel.

[0035] Example 2

[0036] Preparation of a hyperbranched polyamidoamine-chitosan aerogel:

[0037] (1) Diethylenetriamine (41.3 g, 0.4 mol) and dimethyl maleate (28.8 g, 0.2 mol) were added to a 250 mL four-necked flask and stirred for 5 h in an ice bath, then warmed to 100 °C and reacted for 8 h with open mouth, to obtain a viscous yellow liquid, i.e. hyperbranched polyamidoamine.

[0038] (2) 1 g of chitosan was dissolved in a 2% acetic acid solution (50 g), and then the hyperbranched polyamidoamine (1.5 g) obtained in step (1) was added to the above solution, stirred for 3 h to obtain a transparent solution, and then 1 g of glutaraldehyde was slowly dropped into the transparent solution while stirring to obtain a hyperbranched polyamidoamine-chitosan gel, which was then solidified at room temperature for 5 h.

[0039] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) is washed with deionized water for several times, and then freeze-dried at -70°C for 48h to obtain the hyperbranched polyamidoamine-chitosan aerogel.

[0040] Example 3

[0041] Preparation of a hyperbranched polyamidoamine-chitosan aerogel:

[0042] (1) Diethylenetriamine (41.3g, 0.4mol) and dimethyl maleate (28.8g, 0.2mol) are added into a 250ml flask and stirred for 5h under ice-bath condition, then warmed to 100°C and reacted for 8h with open mouth to obtain a viscous yellow liquid, i.e. hyperbranched polyamidoamine.

[0043] (2) 1g of chitosan is dissolved in 50g of 2% acetic acid solution, and then the hyperbranched polyamidoamine (1.7g) obtained in step (1) is added into the above solution, stirred for 3h to obtain a transparent solution, and then 1g of glutaraldehyde is slowly dropped into the transparent solution with stirring to obtain a hyperbranched polyamidoamine-chitosan gel, which is then solidified at room temperature for 5h.

[0044] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) is washed with deionized water for several times, and then freeze-dried at -70°C for 48h to obtain the hyperbranched polyamidoamine-chitosan aerogel.

[0045] Example 4

[0046] Preparation of a hyperbranched polyamidoamine-chitosan aerogel:

[0047] (1) Diethylenetriamine (41.3g, 0.4mol) and dimethyl maleate (28.8g, 0.2mol) are added into a 250ml flask and stirred for 5h under ice-bath condition, then warmed to 100°C and reacted for 8h with open mouth to obtain a viscous yellow liquid, i.e. hyperbranched polyamidoamine.

[0048] (2) 1g of chitosan is dissolved in 50g of 2% acetic acid solution, and then the hyperbranched polyamidoamine (1.7g) obtained in step (1) is added into the above solution, stirred for 3h to obtain a transparent solution, and then 1g of glutaraldehyde is slowly dropped into the transparent solution with stirring to obtain a hyperbranched polyamidoamine-chitosan gel, which is then solidified at room temperature for 5h.

[0049] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) is washed with deionized water for several times, and then freeze-dried at -70°C for 48h to obtain the hyperbranched polyamidoamine-chitosan aerogel.

[0050] Example 5

[0051] Preparation of hyperbranched polyamidoamine-chitosan aerogel

[0052] (1) Diethylenetriamine (41.3 g, 0.4 mol) and dimethyl maleate (28.8 g, 0.2 mol) were added into a 250 mL four-necked flask and stirred for 5 h under ice-bath condition, then warmed to 100 °C and reacted for 8 h with open air to obtain a viscous yellow liquid, which was hyperbranched polyamidoamine.

[0053] (2) 1 g of chitosan was dissolved in 50 g of 2% acetic acid solution, then hyperbranched polyamidoamine (1.9 g) obtained in step (1) was added into the above solution and stirred for 3 h to obtain a transparent solution, then 1 g of glutaraldehyde was slowly dropped into the transparent solution with stirring to obtain hyperbranched polyamidoamine-chitosan gel, which was solidified at room temperature for 5 h.

[0054] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) was washed with deionized water for several times, then freeze-dried at -70 °C for 48 h to obtain hyperbranched polyamidoamine-chitosan aerogel.

[0055] Example 6

[0056] Preparation of hyperbranched polyamidoamine-chitosan aerogel

[0057] (1) Diethylenetriamine (41.3 g, 0.4 mol) and dimethyl maleate (28.8 g, 0.2 mol) were added into a 250 mL four-necked flask and stirred for 5 h under ice-bath condition, then warmed to 100 °C and reacted for 8 h with open air to obtain a viscous yellow liquid, which was hyperbranched polyamidoamine.

[0058] (2) 1 g of chitosan was dissolved in 50 g of 2% acetic acid solution, then hyperbranched polyamidoamine (2.0 g) obtained in step (1) was added into the above solution and stirred for 3 h to obtain a transparent solution, then 1 g of glutaraldehyde was slowly dropped into the transparent solution with stirring to obtain hyperbranched polyamidoamine-chitosan gel, which was solidified at room temperature for 5 h.

[0059] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) was washed with deionized water for several times, then freeze-dried at -70 °C for 48 h to obtain hyperbranched polyamidoamine-chitosan aerogel.

[0060] Example 7

[0061] Preparation of hyperbranched polyamidoamine-chitosan aerogel

[0062] (1) Diethylenetriamine (41.3 g, 0.4 mol) and dimethyl maleate (28.8 g, 0.2 mol) were added to a 250 mL flask and stirred for 5 h in an ice bath, then warmed to 100 °C and left open to react for 8 h to obtain a viscous yellow liquid, which is hyperbranched polyamidoamine.

[0063] (2) 1 g of chitosan was dissolved in 50 g of 2% acetic acid solution, then the hyperbranched polyamidoamine (1.5 g) obtained in step (1) was added to the above solution, stirred for 3 h to obtain a transparent solution, then 1.5 g of glutaraldehyde was slowly dropped into the transparent solution while stirring to obtain a hyperbranched polyamidoamine-chitosan gel, which was then solidified at room temperature for 5 h.

[0064] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) was washed with deionized water for several times, and then freeze-dried at -70 °C for 48 h to obtain a hyperbranched polyamidoamine-chitosan aerogel.

[0065] Example 8

[0066] Preparation of a hyperbranched polyamidoamine-chitosan aerogel:

[0067] (1) Diethylenetriamine (41.3 g, 0.4 mol) and dimethyl maleate (28.8 g, 0.2 mol) were added to a 250 mL flask and stirred for 5 h in an ice bath, then warmed to 100 °C and left open to react for 8 h to obtain a viscous yellow liquid, which is hyperbranched polyamidoamine.

[0068] (2) 1 g of chitosan was dissolved in 50 g of 2% acetic acid solution, then the hyperbranched polyamidoamine (1.5 g) obtained in step (1) was added to the above solution, stirred for 3 h to obtain a transparent solution, then 1.5 g of glutaraldehyde was slowly dropped into the transparent solution while stirring to obtain a hyperbranched polyamidoamine-chitosan gel, which was then solidified at room temperature for 5 h.

[0069] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) was washed with deionized water for several times, and then freeze-dried at -70 °C for 48 h to obtain a hyperbranched polyamidoamine-chitosan aerogel.

[0070] Example 9

[0071] Preparation of a hyperbranched polyamidoamine-chitosan aerogel:

[0072] (1) Diethylenetriamine (41.3 g, 0.4 mol) and dimethyl maleate (28.8 g, 0.2 mol) were added to a 250 mL flask and stirred for 5 h in an ice bath, then warmed to 100 °C and left open to react for 8 h to obtain a viscous yellow liquid, which is hyperbranched polyamidoamine.

[0073] (2) 1 g of chitosan was dissolved in 50 g of 2% acetic acid solution, and 1.7 g of the hyperbranched polyamidoamine obtained in step (1) was added to the solution, stirred for 3 h to obtain a transparent solution, and then 1.5 g of glutaraldehyde was slowly dropped into the transparent solution while stirring to obtain a hyperbranched polyamidoamine-chitosan gel, which was then solidified at room temperature for 5 h.

[0074] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) was washed with deionized water for several times, and then freeze-dried at -70°C for 48 h to obtain a hyperbranched polyamidoamine-chitosan aerogel.

[0075] Example 10

[0076] Preparation of a hyperbranched polyamidoamine-chitosan aerogel:

[0077] (1) Diethylenetriamine (41.3 g, 0.4 mol) and dimethyl maleate (28.8 g, 0.2 mol) were added to a 250 mL four-necked flask, stirred for 5 h under ice-bath conditions, then warmed to 100°C, and reacted for 8 h with open mouth to obtain a viscous yellow liquid, i.e. a hyperbranched polyamidoamine.

[0078] (2) 1 g of chitosan was dissolved in 50 g of 2% acetic acid solution, and 1.7 g of the hyperbranched polyamidoamine obtained in step (1) was added to the solution, stirred for 3 h to obtain a transparent solution, and then 1.5 g of glutaraldehyde was slowly dropped into the transparent solution while stirring to obtain a hyperbranched polyamidoamine-chitosan gel, which was then solidified at room temperature for 5 h.

[0079] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) was washed with deionized water for several times, and then freeze-dried at -70°C for 48 h to obtain a hyperbranched polyamidoamine-chitosan aerogel.

[0080] Example 11

[0081] Preparation of a hyperbranched polyamidoamine-chitosan aerogel:

[0082] (1) Diethylenetriamine (41.3 g, 0.4 mol) and dimethyl maleate (28.8 g, 0.2 mol) were added to a 250 mL four-necked flask, stirred for 5 h under ice-bath conditions, then warmed to 100°C, and reacted for 8 h with open mouth to obtain a viscous yellow liquid, i.e. a hyperbranched polyamidoamine.

[0083] (2) 1 g of chitosan was dissolved in 50 g of 2% acetic acid solution, and 1.7 g of the hyperbranched polyamidoamine obtained in step (1) was added to the solution, stirred for 3 h to obtain a transparent solution, and then 1.5 g of glutaraldehyde was slowly dropped into the transparent solution while stirring to obtain a hyperbranched polyamidoamine-chitosan gel, which was then solidified at room temperature for 5 h.

[0084] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) is washed with deionized water for several times, and then freeze-dried at -70°C for 48h to obtain the hyperbranched polyamidoamine-chitosan aerogel.

[0085] Example 12

[0086] Preparation of a hyperbranched polyamidoamine-chitosan aerogel:

[0087] (1) Diethylenetriamine (41.3g, 0.4mol) and dimethyl maleate (28.8g, 0.2mol) are added into a 250mL four-necked flask, stirred for 5h under ice-bath condition, then warmed to 100°C, and reacted for 8h with open mouth to obtain a viscous yellow liquid, i.e. hyperbranched polyamidoamine.

[0088] (2) 1g of chitosan is dissolved in 50g of 2% acetic acid solution, and then 2.0g of the hyperbranched polyamidoamine obtained in step (1) is added into the above solution, stirred for 3h to obtain a transparent solution, and then 1.5g of glutaraldehyde is slowly dropped into the transparent solution with stirring to obtain a hyperbranched polyamidoamine-chitosan gel, which is then solidified at room temperature for 5h.

[0089] (3) The hyperbranched polyamidoamine-chitosan gel obtained in step (2) is washed with deionized water for several times, and then freeze-dried at -70°C for 48h to obtain the hyperbranched polyamidoamine-chitosan aerogel.

[0090] Example 13

[0091] The basic characterization method and characterization results of the hyperbranched polyamidoamine-chitosan aerogel prepared by the present application are as follows:

[0092] 1. Molecular structure of the hyperbranched polyamidoamine-chitosan aerogel

[0093] Characterization method: Fourier transform infrared spectrometer (Tensor II, USA) is used to characterize the molecular structure of the hyperbranched polyamidoamine-chitosan aerogel in the range of 4000-500cm -1 .

[0094] Characterization results: As shown in the attached Figure 1 figure, the characteristic peak of example 4 at 3380cm -1 is attributed to the stretching vibration of O-H and N-H, the characteristic peak at 1628cm -1 is attributed to amide vibration, the characteristic peaks at 1556cm -1 and 1403cm -1 are characteristic peaks of C=N, and the characteristic peak at 1067cm -1 is attributed to the stretching vibration of C-O-C.

[0095] 2. Microstructure of hyperbranched polyamidoamine-chitosan aerogel

[0096] Characterization method: The microstructure of the hyperbranched polyamidoamine-chitosan aerogel was observed using a scanning electron microscope (sigma 300, USA).

[0097] Characterization results: As shown in the accompanying Figure 2 , the presence of a three-dimensional porous structure can be observed in Example 4, which is conducive to the entry of heavy metal ions into the interior of the hyperbranched polyamidoamine-chitosan aerogel, thereby improving the adsorption efficiency of the hyperbranched polyamidoamine-chitosan aerogel for heavy metal ions.

[0098] Example 14

[0099] The performance detection results of the hyperbranched polyamidoamine-chitosan aerogel prepared by the present application are as follows

[0100] 1. Adsorption performance of hyperbranched polyamidoamine-chitosan aerogel

[0101] Detection results: As shown in the accompanying Figure 3 , the adsorption capacity of Example 4 for hexavalent chromium ions is greater than 370 mg / g, indicating that the hyperbranched polyamidoamine-chitosan aerogel prepared in Example 4 has good removal capacity for hexavalent chromium ions.

[0102] 2. Recycling performance of hyperbranched polyamidoamine-chitosan aerogel

[0103] Detection results: As shown in the accompanying Figure 4 , after four cycles of use, the hyperbranched polyamidoamine-chitosan aerogel prepared in Example 4 still has a removal efficiency of more than 70%, indicating that the hyperbranched polyamidoamine-chitosan aerogel has excellent recycling performance.

Claims

1. A method for preparing hyperbranched polyamidoamine-chitosan aerogel, comprising the following steps: (1) using diethylenetriamine and dimethyl maleate as raw materials, stirring for 4-6 h under ice bath, then increasing the temperature to 90-110℃, and reacting for 7-10 h under open condition to obtain a viscous yellow liquid, i.e. hyperbranched polyamidoamine, (2) dissolving chitosan in dilute acetic acid solution, then adding the hyperbranched polyamidoamine obtained in step (1) into the solution, stirring for 2-4 h to obtain a transparent solution, then adding a crosslinking agent into the transparent solution while stirring to obtain a hyperbranched polyamidoamine-chitosan gel, and then solidifying at room temperature for 4-6 h, wherein the mass ratio of chitosan to dilute acetic acid solution is 1:40-1:100, and the mass ratio of hyperbranched polyamidoamine to dilute acetic acid solution is 3:100-4:100, (3) washing the hyperbranched polyamidoamine-chitosan gel obtained in step (2) with water for multiple times, and then freeze-drying to obtain a hyperbranched polyamidoamine-chitosan aerogel.

2. The method for preparing hyperbranched polyamide amine-chitosan aerogel according to claim 1, characterized in that, In step (1), the molar ratio of diethylenetriamine to dimethyl maleate is 1.5:1-2.5:

1.

3. The method for preparing hyperbranched polyamide amine-chitosan aerogel according to claim 1, characterized in that, In step (2), the mass concentration of the dilute acetic acid solution is 1-5%.

4. The method for preparing hyperbranched polyamide amine-chitosan aerogel according to claim 1, characterized in that, In step (2), the crosslinking agent is epichlorohydrin or glutaraldehyde.

5. The method for preparing hyperbranched polyamide amine-chitosan aerogel according to claim 1, characterized in that, In step (3), the water used for washing is deionized water or pure water.

6. The method for preparing hyperbranched polyamide amine-chitosan aerogel according to claim 1, characterized in that, In step (3), the freeze-drying temperature is less than -60℃, and the freeze-drying time is greater than or equal to 48 h.

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