Chitosan-polyacrylonitrile composite material as well as preparation method and application thereof

Abstract

The invention is applicable to the technical field of materials, and provides a chitosan-polyacrylonitrile composite material as well as a preparation method and application thereof, the structural general formula of the chitosan-polyacrylonitrile composite material is # imgabs0 #, cheap chitosan and polyacrylonitrile fibers are taken as raw materials, and the novel chitosan-polyacrylonitrile composite material is developed; according to the present invention, the dissolvability limitation of chitosan under the acidic condition is overcome, the adsorption capacity of the chitosan on phenolic compounds and heavy metals is enhanced, the selectivity on the target pollutants is high, and the application prospect is broad. Especially, in eight different phenolic compounds (phenol, 4-methylphenol, 4-chlorophenol, 4-nitrophenol, hydroquinone, catechol, resorcinol and phloroglucinol), the adsorbent shows excellent adsorption performance on hydroquinone, and the adsorption capacity reaches up to 316.84 mg.g <-1 >. In addition, the adsorption capacity on soft metal ions Hg < 2 + > is very outstanding, and the maximum adsorption capacity can reach 237.18 mg.g <-1 >.

Description

Technical Field

[0001] This application belongs to the field of materials technology, and particularly relates to a chitosan-polyacrylonitrile composite material, its preparation method, and applications. Background Art

[0002] The continuous development of the manufacturing industry has significantly increased the discharge of organic waste into aquatic ecosystems, thus exacerbating the problem of water resource pollution. Even at trace concentrations, organic pollutants still pose a serious threat to the recycling and sustainable development of water resources. As a type of typical persistent organic pollutant, phenolic compounds are widely used in industrial production processes such as plastics, dyes, and pesticides, and have extremely strong anti-degradability due to the stability of their chemical structures. Once these compounds enter the environment, they are easily enriched in the food chain, posing potential risks to the ecosystem and human health.

[0003] In addition to organic pollutants, heavy metals (such as lead, chromium, and mercury) are also one of the main pollutants in wastewater. The presence of these toxic metals not only significantly reduces the water quality of groundwater and surface water but also poses a serious threat to aquatic ecosystems and terrestrial organisms. Moreover, long-term exposure to heavy metals may cause irreversible damage to important human organs (such as the liver, kidneys, brain, and nervous system), and even have carcinogenicity or cause acute poisoning at high concentrations.

[0004] Among many water pollution control technologies, the adsorption method is widely regarded as one of the most promising pollutant removal technologies due to its simple operation, low energy consumption, recyclability, and high treatment efficiency. Currently, a variety of efficient adsorption materials have been developed for removing organic pollutants and heavy metals from wastewater. However, despite certain progress in removing pollutants by these materials, they still face the problem of low selectivity and are difficult to efficiently separate phenolic pollutants and heavy metal ions. Therefore, developing adsorption materials with higher selectivity, larger adsorption capacity, and better regeneration performance remains the core challenge in the current field of water pollution treatment. Summary of the Invention

[0005] The purpose of the embodiments of this application is to provide a chitosan-polyacrylonitrile composite material, aiming to solve the problem that existing efficient adsorption materials have low selectivity and are difficult to efficiently separate phenolic pollutants and heavy metal ions.

[0006] The embodiments of this application are implemented as follows. A chitosan-polyacrylonitrile composite material, the structural general formula of the chitosan-polyacrylonitrile composite material is:

[0007]

[0008] The embodiments of this application also provide a preparation method of the above chitosan-polyacrylonitrile composite material, including:

[0009] The modified polyacrylonitrile fibers dissolved in N-methylpyrrolidone are uniformly mixed with copper sulfate pentahydrate and L-ascorbic acid sodium dissolved in water to obtain a first mixture;

[0010] Modified chitosan is added to the first mixture for stirring reaction, and after filtration and washing, a second mixture is obtained;

[0011] The second mixture is placed in an acid solution for mixing and stirring. After filtration, the obtained solid is put into a sodium carbonate solution for mixing and stirring, and after filtration, washing and drying, a chitosan-polyacrylonitrile composite material is obtained.

[0012] The embodiment of the present application also provides an application of the above chitosan-polyacrylonitrile composite material in adsorbing organic pollutants and heavy metal ions.

[0013] The embodiment of the present application uses cheap chitosan and polyacrylonitrile fibers as raw materials to successfully develop a new chitosan-polyacrylonitrile composite material, which overcomes the solubility limitation of chitosan under acidic conditions and simultaneously enhances its adsorption capacity for phenolic compounds and heavy metals. Compared with chitosan, the internal structure of the chitosan-polyacrylonitrile composite material is more compact, which is mainly attributed to the structural confinement effect of polyacrylonitrile. This structural modification endows the chitosan-polyacrylonitrile composite material with higher selectivity for target pollutants. Especially among eight different phenolic compounds (phenol, 4-methylphenol, 4-chlorophenol, 4-nitrophenol, hydroquinone, catechol, resorcinol and phloroglucinol), hydroquinone shows excellent adsorption performance, and the adsorption capacity is as high as 316.84 mg·g -1 . In addition, the adsorption capacity of the chitosan-polyacrylonitrile composite material for the soft metal ion Hg 2+ is also very prominent, and the maximum adsorption amount can reach 237.18 mg·g -1 . Description of the Drawings

[0014] Figure 1 is the TEM diagram of PAN-CS and CS provided in Example 1 of the present application;

[0015] Figure 2 is the infrared spectrum diagram of different functionalized materials provided in Example 1 of the present application. Detailed Embodiments

[0016] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0017] The present application provides a chitosan-polyacrylonitrile composite material, the chitosan-polyacrylonitrile composite material has the general structural formula:

[0018]

[0019] In the examples of the present application, the chitosan-polyacrylonitrile composite material (PAN-CS) is formed by combining modified chitosan and modified polyacrylonitrile by chemical bonding, and is used for the adsorption and removal of phenolic pollutants and heavy metal ions. This material not only has the high adsorption performance of chitosan and the acid resistance of polyacrylonitrile fiber, but also significantly improves the structural stability and pollutant selectivity of the material.

[0020] Among them, chitosan is a natural polymer material derived from chitin. Due to its excellent biocompatibility, biodegradability, high-efficiency adsorption performance and good functionalization potential, it has attracted much attention in the fields of environmental protection and industrial applications. However, the application of chitosan is limited under certain environmental conditions, especially in weakly acidic solutions, where it is prone to acid degradation and gelation, resulting in reduced dispersibility in the aqueous phase and affecting its ability to complex metal ions through hydroxyl and amino groups, thereby limiting its adsorption performance.

[0021] Polyacrylonitrile Fiber (PANF) is an acid-resistant material with rich cyanide groups on its surface, which can be converted into a variety of functional groups through chemical modification. Studies have shown that functionalized PANF can exhibit high selective adsorption capacity for specific pollutants in the process of water pollution control, providing an important scientific basis for its precise application in wastewater treatment. Therefore, by rationally designing functionalized PANF and optimizing its interaction mechanism with pollutants, it is expected to further enhance its application value in the field of water pollution control.

[0022] The present application also provides a method for preparing the chitosan-polyacrylonitrile composite material, comprising the following steps:

[0023] Step S1: Dissolve modified polyacrylonitrile fiber (PAN) in N-methylpyrrolidone P F), uniformly mixed with copper sulfate pentahydrate and sodium L-ascorbate dissolved in water to obtain a first mixture.

[0024] Step S2: adding modified chitosan (BNCS) to the first mixture for stirring reaction, filtering and washing to obtain a second mixture (PAN-BCS).

[0025] Step S3: Place the second mixture in an acid solution for mixing and stirring. After filtration, put the obtained solid into a sodium carbonate solution for mixing and stirring. After filtration, washing, and drying, a chitosan-polyacrylonitrile composite material (PAN-CS) is obtained.

[0026] The reaction route is as follows:

[0027]

[0028] Optionally, the preparation method of the modified polyacrylonitrile fiber includes: Stirring and reacting polyacrylonitrile fiber (PAN P F), propargylamine, and deionized water under boiling reflux conditions. After the reaction, clamp out the fiber, wash it, and dry it to obtain the modified polyacrylonitrile fiber (PAN P F). The reaction route is as follows:

[0029]

[0030] More specifically, the preparation method of the modified polyacrylonitrile fiber includes: Add 1.00 g of polyacrylonitrile fiber, 10.0 mL of propargylamine, and 30.0 mL of deionized water to a round-bottom flask. The mixture is stirred and reacted under boiling reflux conditions for 24 hours. After the reaction, clamp out the fiber, wash it repeatedly with ethanol, and dry it to obtain the modified polyacrylonitrile fiber.

[0031] Optionally, the uniform mixing of the modified polyacrylonitrile fiber dissolved in N-methylpyrrolidone with copper sulfate pentahydrate and L-ascorbic acid sodium dissolved in water to obtain the first mixture includes:

[0032] Dissolve 1.00 g of modified polyacrylonitrile fiber in 50.0 mL of N-methylpyrrolidone at 130 °C. After the solution cools to room temperature, add 0.32 g of copper sulfate pentahydrate and 0.52 g of L-ascorbic acid sodium dissolved in 1.0 mL of water thereto, and stir evenly to obtain the first mixture.

[0033] Optionally, the preparation method of the modified chitosan includes: Dissolve chitosan (CS) in an acetic acid solution, add methanol for uniform mixing, and then slowly dropwise add a benzaldehyde-methanol solution for mixing reaction. After the reaction, slowly add a sodium hydroxide solution until no white precipitate is produced in the solution. After washing and drying, a first modified product (BCS) is obtained; After swelling the first modified product in a sodium hydroxide solution, slowly add a p-toluenesulfonyl chloride-chloroform solution for stirring reaction. After filtration and washing, a second modified product (BTCS) is obtained; Stir and react the second modified product, sodium azide, and N,N-dimethylformamide. After filtration and washing, a modified chitosan (BNCS) is obtained. The reaction route is as follows:

[0034]

[0035] More specifically, the preparation method of the modified chitosan includes: dissolving chitosan in an acetic acid solution, adding methanol and stirring until the solution is uniformly mixed, then slowly dropping in a benzaldehyde-methanol solution, heating to 60 °C, reacting for 3 hours. After the reaction ends, slowly add a sodium hydroxide solution until no white precipitate is produced in the solution. After washing and drying, a first modified product is obtained; swelling the first modified product in a sodium hydroxide solution for 1 hour, then at 0 °C, slowly dropping in a p-toluenesulfonyl chloride-chloroform solution, and stirring and reacting at 0 °C for 1 hour. The reaction mixture is then transferred to 30 °C and stirring and reacting is continued for 10 hours. After filtration and washing, a second modified product is obtained; adding the second modified product, sodium azide and N,N-dimethylformamide into a round-bottom flask equipped with a condenser reflux, stirring and reacting at 80 °C for 4 hours. After filtration and washing, modified chitosan is obtained.

[0036] Optionally, adding modified chitosan to the first mixture for stirring and reacting, and after filtration and washing, obtaining a second mixture, includes:

[0037] Adding 0.67 g of modified chitosan to the first mixture, continuing to stir at 30 °C for 24 hours. After the reaction is completed, pour the mixture into 100.0 mL of water, filter and wash the solid with water and ethanol to obtain a second mixture.

[0038] Optionally, placing the second mixture in an acid solution for mixing and stirring, after filtration, putting the obtained solid into a sodium carbonate solution for mixing and stirring, and after filtration, washing and drying, obtaining a chitosan-polyacrylonitrile composite material, includes:

[0039] Putting the second mixture into 40.0 mL of 2.0 M hydrochloric acid solution, stirring at 40 °C for 4 hours and then filtering. Putting the obtained solid into 40.0 mL of 1.0 M sodium carbonate solution, stirring at room temperature for 1 hour, filtering, washing the solid with water and ethanol, and drying at 60 °C to obtain a chitosan-polyacrylonitrile composite material.

[0040] The embodiment of the present application also provides an application of the above-mentioned chitosan-polyacrylonitrile composite material in adsorbing organic pollutants and heavy metal ions.

[0041] The following uses specific examples to describe in detail the chitosan-polyacrylonitrile composite material, its preparation method and application, as shown below. The experimental methods used in the following examples are all conventional methods unless otherwise specified; the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0042] Example 1: Preparation of Chitosan-Polyacrylonitrile Composite

[0043] Chitosan (CS, 0.75 g) with a deacetylation degree of 93.4% was dissolved in a 2 wt% acetic acid solution and placed in a 100 mL round-bottom flask. Subsequently, methanol (70.0 mL) was added, and the solution was stirred with a magnetic stirrer until evenly mixed. Then, benzaldehyde (2.00 g) was diluted in methanol (30.0 mL), and this solution was slowly added dropwise to the chitosan-methanol solution. The mixed solution was heated to 60 °C and reacted for 3 hours. After the reaction, a 5% sodium hydroxide solution was slowly added until no white precipitate was formed in the solution. Subsequently, stirring was continued for 30 minutes, and the solid was filtered and washed alternately with water and methanol. Finally, the solid was dried at 60 °C to obtain a white solid BCS (0.98 g).

[0044] BCS (0.76 g) was swollen in a 1% sodium hydroxide solution (10.0 mL) for 1 hour. Then, at 0 °C, p-toluenesulfonyl chloride (2.90 g) dissolved in chloroform (50.0 mL) was slowly added dropwise to the swollen BCS solution, and the reaction was stirred at this temperature for 1 hour. The reaction mixture was then transferred to 30 °C and the stirring reaction was continued for 10 hours. After the reaction, the solid was filtered and washed with ethanol. Finally, the solid was dried at 60 °C to obtain a white solid BTCS (0.70 g).

[0045] BTCS (0.62 g), sodium azide (0.30 g), and N,N-dimethylformamide (30.0 mL) were added to a round-bottom flask equipped with a condenser reflux, and the reaction was stirred at 80 °C for 4 hours. After the reaction, the solid was filtered and washed with water and ethanol. Finally, the solid was dried at 60 °C to obtain a light yellow solid BNCS (0.48 g).

[0046] The dried PANF (1.00 g), propargylamine (10.0 mL), and deionized water (30.0 mL) were added to a round-bottom flask, and the mixture was stirred and reacted under boiling reflux conditions for 24 hours. After the reaction, the fibers were taken out, washed repeatedly with ethanol, and after cleaning, the fibers were placed in an oven at 60 °C and dried for more than 8 hours to obtain orange fibers PAN P F.

[0047] PAN PF (1.00 g) was dissolved in N-methylpyrrolidone (50.0 mL) at 130 °C. After the solution was cooled to room temperature (25 °C), CuSO4·5H2O (0.32 g) dissolved in water (1.0 mL) and sodium L-ascorbate (0.52 g) were added thereto, and the mixture was stirred evenly. Subsequently, BNCS (0.67 g) was added, and stirring was continued at 30 °C for 24 hours. After the reaction was completed, the mixture was poured into water (100.0 mL), and the solid was filtered and washed with water and ethanol to obtain a brown powder PAN-BCS. Then, PAN-BCS was put into a 2.0 M HCl solution (40.0 mL), stirred at 40 °C for 4 hours and then filtered. Subsequently, the solid was put into a 1.0 M Na2CO3 solution (40.0 mL), stirred at room temperature for 1 hour. The solid was filtered, washed with water and ethanol, and finally dried at 60 °C to obtain a brown powder of chitosan-polyacrylonitrile composite PAN-CS (1.39 g).

[0048] TEM tests were respectively carried out on chitosan CS and chitosan-polyacrylonitrile composite PAN-CS in Example 1, and the test results are as Figure 1 shown, where Figure 1 (a)-(c) are TEM images of PAN-CS, Figure 1 (d)-(f) are TEM images of CS. It can be seen from Figure 1 that compared with CS, the particles of PAN-CS are arranged more closely. This phenomenon can be attributed to the regional restriction effect exerted by the modified polyacrylonitrile polymer chain segments on the chitosan molecular chain segments during the reaction process. This effect promotes the closer arrangement of the polymer chain segments, thus forming a more compact structure.

[0049] Furthermore, IR spectrum tests were respectively carried out on CS, BCS, BTCS, BNCS, PANF, PAN P F, PAN-BCS and PAN-CS in Example 1, and the test results are as Figure 2 shown. It can be known from Figure 2 that at 1639 cm -1 , BCS showed a stretching vibration absorption peak of the C=N bond, and characteristic absorption peaks of a monosubstituted benzene ring appeared at 755 cm -1 and 690 cm -1 , indicating the successful formation of the imine bond. The para-position benzene ring bending vibration absorption peak at 818 cm -1 confirmed the introduction of the tosyl group. In the spectrum of BNCS, the stretching vibration absorption peak at 2106 cm -1 indicated the successful introduction of the azide group. In the PANF spectrum, there was a stretching vibration absorption peak of the C≡N bond at 2244 cm -1 . PAN PThe C=O stretching vibration absorption peak at 1660 cm -1 appears. In the PAN-BCS spectrum, both the characteristic peaks of PAN p F (C≡N, 2244 cm -1 ) and those of BNCS (-OH, 3500 cm -1 ; aromatic ring, 755 cm -1 and 690 cm -1 ) are present. After hydrolysis of the imine, the bending vibration absorption peak of the monosubstituted benzene ring disappears in the PAN-CS spectrum.

[0050] Example 2: Adsorption of phenolic compounds by PAN-CS

[0051] 10 mg of dry PAN-CS was immersed in a solution containing phenolic pollutants (volume 40 mL, initial concentration 1 mmol L -1 ). After stirring at room temperature until adsorption equilibrium was reached, the absorbance was measured at the maximum absorption wavelength of each pollutant using a UV spectrophotometer, and the corresponding concentration was calculated according to the corresponding standard curve. The adsorption performance of PAN-CS for phenolic pollutants was calculated from the decrease in the concentration of the substance before and after adsorption. The results are shown in Table 1. The adsorption amount calculation formula is as follows:

[0052]

[0053] q e is the equilibrium adsorption amount of PAN-CS for phenolic pollutants (mg g -1 ), C0 and C e correspond to the starting and ending concentrations of adsorption (mg L -1 ), V is the volume of the pollutant (L), and m is the mass of PAN-CS (g).

[0054] Table 1. Adsorption capacity of PAN-CS for different phenolic substances

[0055] Adsorbed substance <![CDATA[Adsorption capacity (mmol g -1 )]]> 1 Phenol 0 2 Phloroglucinol 0.01 3 Catechol 0.01 4 Resorcinol 0.03 5 4-Methylphenol 0.05 6 4-Chlorophenol 0.11 7 4-Nitrophenol 0.33 8 Hydroquinone 2.81

[0056] Example 3: Adsorption of heavy metal ions by PAN-CS

[0057] 10 mg of dry PAN-CS was immersed in a solution containing heavy metal ions (volume 40 mL, initial concentration 1 mmol L -1 ). After stirring at room temperature until adsorption equilibrium was reached, the absorbance was measured using ICP-OES, and the corresponding concentration was calculated according to the corresponding standard curve. The adsorption performance of PAN-CS for heavy metal ions was calculated from the decrease in the concentration of the substance before and after adsorption. The adsorption amount calculation formula is the same as above.

[0058] Table 2. Adsorption Capacity of PAN-CS for Different Heavy Metal Ions

[0059]

[0060]

[0061] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

[0062] The foregoing is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A chitosan-polyacrylonitrile composite material, characterized in that: The general structural formula of the chitosan-polyacrylonitrile composite material is:

2. A method for preparing the chitosan-polyacrylonitrile composite material according to claim 1, characterized in that: include: uniformly mixing modified polyacrylonitrile fiber dissolved in N-methylpyrrolidone with copper sulfate pentahydrate and sodium L-ascorbate dissolved in water to obtain a first mixture; Adding modified chitosan to the first mixture for stirring reaction, filtering and washing to obtain a second mixture; The second mixture is placed in an acid solution for mixing and stirring. After filtering, the obtained solid is placed in a sodium carbonate solution for mixing and stirring. After filtering, washing and drying, a chitosan-polyacrylonitrile composite material is obtained.

3. The method for preparing the chitosan-polyacrylonitrile composite material according to claim 2, characterized in that: The preparation method of the modified polyacrylonitrile fiber comprises: The polyacrylonitrile fiber, propargylamine and deionized water are stirred and reacted under boiling reflux conditions. After the reaction is completed, the fiber is clamped out, washed and dried to obtain modified polyacrylonitrile fiber.

4. The method for preparing the chitosan-polyacrylonitrile composite material according to claim 3, characterized in that: The preparation method of the modified polyacrylonitrile fiber comprises: 1.00 g of polyacrylonitrile fiber, 10.0 mL of propargylamine and 30.0 mL of deionized water were added into a round-bottom flask, and the mixture was stirred and reacted under boiling reflux conditions for 24 hours. After the reaction was completed, the fiber was clamped out, repeatedly washed with ethanol, and dried to obtain modified polyacrylonitrile fiber.

5. The method for preparing the chitosan-polyacrylonitrile composite material according to claim 2, characterized in that: The preparation method of the modified chitosan comprises: After chitosan is dissolved in an acetic acid solution, methanol is added to mix uniformly, and then a benzaldehyde-methanol solution is slowly added dropwise to carry out a mixing reaction. After the reaction is completed, a sodium hydroxide solution is slowly added until no white precipitate is generated in the solution, and the first modified product is obtained after washing and drying; The first modified product is placed in a sodium hydroxide solution for swelling treatment, and then a p-toluenesulfonyl chloride-chloroform solution is slowly added to carry out stirring reaction, and the mixture is filtered and washed to obtain a second modified product; The second modified product, sodium azide and N,N-dimethylformamide are stirred for reaction, filtered and washed to obtain modified chitosan.

6. The method for preparing the chitosan-polyacrylonitrile composite material according to claim 5, characterized in that: The preparation method of the modified chitosan comprises: Dissolve chitosan in acetic acid solution, add methanol and stir until the solution is evenly mixed, then slowly drop benzaldehyde-methanol solution, heat to 60°C, react for 3 hours, and after the reaction is completed, slowly add sodium hydroxide solution until no more white precipitate is produced in the solution, wash and dry to obtain a first modified product; After the first modified product was placed in a sodium hydroxide solution to swell for 1 hour, p-toluenesulfonyl chloride-chloroform solution was slowly added dropwise at 0°C, and stirred for reaction at 0°C for 1 hour. The reaction mixture was then transferred to 30°C, and stirred for reaction for 10 hours. After filtering and washing, a second modified product was obtained. The second modified product, sodium azide and N,N-dimethylformamide were added into a round-bottom flask with a condenser reflux device, stirred and reacted at 80° C. for 4 hours, and then filtered and washed to obtain modified chitosan.

7. The method for preparing the chitosan-polyacrylonitrile composite material according to claim 2, characterized in that: The modified polyacrylonitrile fiber dissolved in N-methylpyrrolidone is uniformly mixed with copper sulfate pentahydrate and sodium L-ascorbate dissolved in water to obtain a first mixture, comprising: 1.00 g of modified polyacrylonitrile fiber was dissolved in 50.0 mL of N-methylpyrrolidone at 130° C. After the solution was cooled to room temperature, 0.32 g of copper sulfate pentahydrate and 0.52 g of sodium L-ascorbate dissolved in 1.0 mL of water were added thereto and stirred uniformly to obtain a first mixture.

8. The method for preparing the chitosan-polyacrylonitrile composite material according to claim 7, characterized in that: The modified chitosan is added to the first mixture for stirring reaction, and the mixture is filtered and washed to obtain a second mixture, comprising: 0.67 g of modified chitosan was added to the first mixture, and stirring was continued at 30° C. for 24 hours. After the reaction was completed, the mixture was poured into 100.0 mL of water, filtered, and the solid was washed with water and ethanol to obtain a second mixture.

9. The method for preparing the chitosan-polyacrylonitrile composite material according to claim 8, characterized in that: The second mixture is placed in an acid solution for mixing and stirring, filtered, and then the obtained solid is placed in a sodium carbonate solution for mixing and stirring, filtered, washed, and dried to obtain a chitosan-polyacrylonitrile composite material, including: The second mixture was placed in 40.0 mL of 2.0 M hydrochloric acid solution, stirred at 40° C. for 4 hours and filtered. The obtained solid was placed in 40.0 mL of 1.0 M sodium carbonate solution, stirred at room temperature for 1 hour, filtered, washed with water and ethanol, and dried at 60° C. to obtain a chitosan-polyacrylonitrile composite material.

10. Use of the chitosan-polyacrylonitrile composite material according to claim 1 in adsorbing organic pollutants and heavy metal ions.

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