Polyacrylonitrile-based chelate fiber as well as preparation method and application thereof
The polyacrylonitrile-based chelated fibers prepared by microwave-assisted method and solvothermal method solve the problems of low extraction efficiency and unfriendly environment of gallium and indium, and achieve efficient and rapid adsorption and separation of dilute metal elements.
Patent Information
- Application Number
- CN202510295808.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-13
- Publication Date
- 2025-07-25
AI Technical Summary
In the prior art, the wet extraction efficiency of gallium and indium is low, the kinetic performance is poor and the environment is unfriendly, especially in low concentration conditions, which lead to low efficiency and organic pollution.
The microwave-assisted method is used to catalyze the hydrolysis of polyacrylonitrile fibers in alkaline solution, combined with acid solution soaking and solvothermal method to catalyze the amination to prepare polyacrylonitrile-based chelating fibers containing amine groups and amide groups. The functional groups on the surface of the fiber are coordinated with metal ions and the impurities are removed by ultrasonic cleaning.
The adsorption capacity and adsorption speed of gallium and indium are improved, the generation of organic pollutants is reduced, and efficient and environmentally friendly extraction and separation of rare metal elements are achieved.
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Figure CN120367038A_ABST
Abstract
Description
Technical Field:
[0001] The present invention relates to the field of polymer modification, and particularly to a polyacrylonitrile-based chelating fiber and its preparation method and application. Background Art:
[0002] Currently, gallium and indium belong to the rare and dispersed metals of the boron group (ШA), which are the supporting materials for high-tech new materials and play an important role in fields such as aerospace, energy, and communication. However, the above rare and dispersed metals have no independent mineral deposits in the earth's crust and mostly occur in aluminum or zinc minerals. The contents of gallium and indium elements are extremely low and widely distributed. Under the background of energy conservation, consumption reduction, and pollution reduction, it is of great significance to study the efficient, clean, and short-process extraction of rare and dispersed metals such as gallium and indium.
[0003] Currently, both gallium and indium can be extracted by solvent extraction method and resin adsorption method. In the sulfuric acid system, gallium and indium can be extracted by hydroxamic acid. In the alkaline system, gallium can be adsorbed by amidoxime chelating resin; in the sulfuric acid system, indium can be adsorbed by ion exchange resin. Due to the low concentration of rare and dispersed metal ions in the solution, in order to achieve a high direct recovery rate of metals, multi-stage extraction must be carried out. It can be seen that the efficiency of the existing extraction processes is low. In addition, the extraction method produces organic pollutants, which cause certain harm to water bodies. Although the chelating resin method is convenient, fast, reusable, and has little environmental pollution, it is chemically cross-linked, and the diffusion rate inside the resin microspheres is slow, and the time required for the metal ions to reach the adsorption equilibrium is relatively long. Summary of the Invention:
[0004] The purpose of the present invention is to provide a polyacrylonitrile-based chelating fiber and its preparation method and application, which solve the problems of low extraction efficiency, poor kinetic performance, and environmental unfriendliness in the wet treatment of rare and dispersed metals such as gallium and indium in the prior art.
[0005] The present invention is realized by the following technical solutions:
[0006] A preparation method of a polyacrylonitrile-based chelating fiber, the method comprising the following steps:
[0007] (1) Using the ultrasonic method to alternately clean the surface of polyacrylonitrile fiber with water and a lower alcohol as two solvents to obtain a clean polyacrylonitrile fiber;
[0008] (2) Using the microwave-assisted method to catalytically hydrolyze the clean polyacrylonitrile fiber in an alkaline solution at 90-100 °C to obtain a polyacrylonitrile fiber containing carboxylate; the microwave power is 200-600 W, and the hydrolysis time is 0.5-1.0 h;
[0009] (3) Washing the polyacrylonitrile-based fiber obtained in step (2) with pure water to wash away the alkali solution attached to the fiber surface, and the washing end point is that the pH value of the washing water is close to 7.0;
[0010] (4) Immerse the polyacrylonitrile-based fiber containing carboxylate obtained in step (3) in acid solution for 1 - 4 h, and then wash it with pure water to remove the acid solution adhering to the fiber surface. The washing end point is when the pH value of the wash water is close to 7.0, obtaining a polyacrylonitrile-based fiber containing carboxyl groups;
[0011] (5) Catalyze the amination of the polyacrylonitrile-based fiber containing carboxyl groups obtained in step (4) in a polyamine solution at 100 - 130 °C by the solvothermal method. The cyano groups and carboxyl groups on the polyacrylonitrile-based fiber containing carboxyl groups undergo condensation reactions with the polyamine to obtain a crude polyacrylonitrile-based chelating fiber containing amino groups and amide groups; the solvent used is water, ethylene glycol, or a mixed solvent composed of water and ethylene glycol, with ethylene glycol being preferred. The catalyst used is aluminum trichloride, tin tetrachloride, lanthanum chloride, or cerium chloride, with cerium chloride being preferred;
[0012] (6) Alternately wash the crude chelating fiber with two solvents, water and lower alcohol, by the ultrasonic method; then dry it at 50 - 70 °C for 0.5 - 2.0 h to remove the moisture and alcohol adsorbed on the surface of the wet chelating fiber, obtaining a dry polyacrylonitrile-based chelating fiber containing amide groups and amino groups.
[0013] The lower alcohol described in step (1) is methanol or ethanol, with ethanol being preferred. The ultrasonic frequency used in the ultrasonic method in step (1) is 20 - 40 kHz, the average sound intensity is 1.0 - 2.0 W / cm 2 , the temperature is from room temperature to 40 °C, and the time is 5 - 10 min.
[0014] In step (1), the ultrasonic method is used to alternately wash the polyacrylonitrile fiber with two solvents, water and lower alcohol, to remove the ash and oil stains on the fiber surface. Since the polyacrylonitrile fiber has a certain adsorption effect, the fiber surface usually adsorbs ash, oil stains, and gas. The principle of ultrasonic cleaning is that when ultrasonic waves with a certain frequency and sound intensity irradiate the liquid, under the action of the negative pressure phase of the sound wave, the jet generated by the liquid impacts the dirt on the fiber surface, obtaining a clean fiber surface.
[0015] In step (2), in a microwave field and under the catalytic action of an alkali, the polyacrylonitrile fiber undergoes a certain degree of hydrolysis to obtain a fiber containing sodium carboxylate.
[0016] The alkali used is one of sodium hydroxide, potassium hydroxide, and sodium carbonate, with sodium hydroxide being preferred.
[0017] When sodium carbonate is selected, the alkali solution concentration is 2.0 wt% - 10 wt%; when sodium hydroxide is selected, the alkali solution concentration is 0.5 wt% - 2.0 wt%; when potassium hydroxide is selected, the alkali solution concentration is 0.5 wt% - 2.0 wt%.
[0018] The solid-liquid ratio of the polyacrylonitrile fiber to the alkali solution is 1 g : 20 - 40 mL.
[0019] In step (4), the acid used in the acid solution is one of hydrochloric acid and sulfuric acid, and hydrochloric acid is preferred.
[0020] When hydrochloric acid is selected, the concentration of hydrochloric acid is 0.1 - 1.0 mol / L; when sulfuric acid is selected, the concentration of sulfuric acid is 0.05 - 0.5 mol / L.
[0021] The solid-liquid ratio of the polyacrylonitrile-based fiber to the acid solution is 1 g: 20 - 40 mL.
[0022] The polyamine used in step (5) is one of ethylenediamine, diethylenetriamine, and triethylenetetramine, and diethylenetriamine is preferred.
[0023] The volume concentration of polyamine in the polyamine solution is 20 vol% - 50 vol%, and the solid-liquid ratio of the polyacrylonitrile-based fiber to the polyamine solution is 1 g: 20 - 80 mL.
[0024] The dosage of the catalyst is 0.25 wt% - 5.0 wt% of the fiber amount, and the reaction time is 2 - 6 h.
[0025] Step (6) is to alternately wash the solvent attached to the fiber surface and the residual reactants with water and a lower alcohol by ultrasonic method. The lower alcohol is methanol or ethanol, and ethanol is preferred. The ultrasonic frequency used is 20 - 40 kHz, the average sound intensity is 1.0 - 2.0 W / cm 2 , the temperature is from room temperature to 40 °C, and the time is 5 - 10 min.
[0026] The present invention also protects the polyacrylonitrile-based chelating fiber obtained by the above preparation method. Using the polyacrylonitrile fiber as the skeleton, the functional groups coordinated with metal ions on the skeleton are amino groups and amide groups. The coordinating atom nitrogen in the functional groups is bonded to the carbon atom in the form of a covalent bond. The loading amounts of the amide group and the amino group are 2 - 10 mmol / g of dry polyacrylonitrile fiber.
[0027] Polyacrylonitrile fiber (PAN fiber) is an industrial fiber with good mechanical strength, chemical stability, and thermal stability. The skeleton has a large aspect ratio, and the specific surface area is more than 5 - 6 times that of polyacrylonitrile macroporous resin. The present invention uses the microwave-assisted method to catalytically hydrolyze and clean the polyacrylonitrile fiber in an alkaline solution, and then uses the solvothermal method to catalytically aminate after soaking and washing with an acid solution to modify the surface of the PAN fiber to obtain a crude polyacrylonitrile-based chelating fiber containing amino groups and amide groups, thereby obtaining a chelating fiber containing more coordinating atoms and distributed on the fiber surface. Due to the small diameter, large specific surface area of the chelating fiber, the functional groups are distributed on the fiber surface, and it has good selectivity and kinetic performance, so the adsorption rate of rare metal elements such as gallium and indium is faster and the adsorption capacity is higher, and it has good development prospects in the field of enrichment and separation of rare metal elements such as gallium and indium.
[0028] Therefore, the present invention also protects the application of the polyacrylonitrile-based chelating fiber obtained by the above preparation method in the adsorption, separation or enrichment of scarce metal ions such as gallium and indium.
[0029] The beneficial effects of the present invention are as follows: The present invention uses a microwave-assisted method to catalytically hydrolyze clean polyacrylonitrile fibers in an alkaline solution, and after soaking and washing in an acid solution, a solvothermal method is used to catalytically aminate at 100-130 °C to modify the surface of the PAN fibers, obtaining a crude polyacrylonitrile-based chelating fiber containing amino and amide groups, and then purifying to obtain the polyacrylonitrile-based chelating fiber. The fiber of the present invention is a chelating fiber containing more coordination atoms and distributed on the fiber surface, with a large specific surface area, a high saturated adsorption capacity for gallium / indium ions, and a relatively fast adsorption rate; and no organic pollutants are generated during the adsorption and separation process, which is relatively friendly to the environment. Description of the drawings:
[0030] Figure 1 is the infrared spectrum of the polyacrylonitrile-based chelating fiber obtained in Example 1 of the present invention.
[0031] Figure 2 is the microscopic morphology diagram of the polyacrylonitrile-based chelating fiber obtained in Example 4 of the present invention. Specific implementation manners:
[0032] The following is a further description of the present invention, rather than a limitation of the present invention.
[0033] Example 1:
[0034] Take 0.5 g of polyacrylonitrile fiber, under the conditions of a power of 25 kW, an acoustic intensity of 1.5 W / cm 2 and room temperature, first ultrasonically clean in water for 5 min, and then ultrasonically clean in ethanol for 5 min to obtain clean polyacrylonitrile fiber. Under a microwave power of 200 W and a temperature of 90 °C, place the clean polyacrylonitrile fiber in 15 mL of 0.5% sodium hydroxide solution and catalytically hydrolyze for 0.5 h, separate to obtain polyacrylonitrile fiber containing carboxylate sodium, and then wash with water until the pH value of the wash water is 7.0. Immerse the above fiber in 15 mL of 1.0 mol / L hydrochloric acid solution for 2 h, separate to obtain polyacrylonitrile fiber containing carboxylic acid, and then wash with water until the pH value of the wash water is close to 7.0. Place the wet polyacrylonitrile fiber in 40 mL of an aqueous solution composed of 25% ethylenediamine and 5 mg of aluminum trichloride, and catalytically aminate at 120 °C for 3 h. After separation, under the conditions of a power of 25 kW, an acoustic intensity of 1.5 W / cm 2 and room temperature, first ultrasonically clean in water for 5 min, and then ultrasonically clean in ethanol for 5 min to obtain clean wet polyacrylonitrile-based chelating fiber. Finally, perform a drying treatment at 50 °C for 2 h to obtain dry polyacrylonitrile-based chelating fiber. Its infrared spectrum is as Figure 1 shown, and in the curve, 1075 cm-1 corresponds to the stretching vibration of amine C-N at 3199 cm -1 the broad peak and the sharp peak at 1582 cm -1 correspond to the stretching vibration and in-plane bending vibration peaks of amine N-H respectively; the C=O stretching vibration peak appears at 1610 cm -1 The appearance of the above characteristic peaks indicates that the polyacrylonitrile-based chelating fiber has been successfully grafted with amide groups and amine groups.
[0035] The elemental content of the chelating fiber is analyzed. According to the oxygen content, the grafting amount of amide groups can be calculated. Then, by subtracting the grafting amount of amide groups from the consumption of the aminating agent, the grafting amount of amine groups can be calculated. Through chemical analysis, the loading amounts of amine groups and amide groups on the prepared polyacrylonitrile-based chelating fiber are 4 mmol / g of dry fiber, and it has a high adsorption capacity for metal ions.
[0036] The repeating unit structure of the polyacrylonitrile-based chelating fiber obtained in this example is as follows:
[0037]
[0038] where R is a methylene group with 2 carbon atoms and n is the degree of polymerization.
[0039] 0.01 g of polyacrylonitrile-based chelating fiber is soaked in 100 mL of an acidic solution containing 500 mg of Ga 3+ The equilibrium time is only 10 min, indicating that the amine-containing chelating fiber has a high adsorption rate.
[0040] Example 2
[0041] Take 1.0 g of polyacrylonitrile fiber. Under the conditions of a power of 35 kW, an acoustic intensity of 1.5 W / cm 2 and room temperature, first ultrasonically clean it in water for 8 min, and then ultrasonically clean it in ethanol for 10 min to obtain clean polyacrylonitrile fiber. Under the conditions of a microwave power of 400 W and a temperature of 100 °C, place the clean polyacrylonitrile fiber in 30 mL of 1% sodium hydroxide solution for catalytic hydrolysis for 0.5 h, and separate the polyacrylonitrile fiber containing sodium carboxylate. Then wash it with water until the wash water is neutral. Soak the above fiber in 35 mL of 0.5 mol / L sulfuric acid solution for 2 h, and separate the polyacrylonitrile fiber containing carboxylic acid. Then wash it with water until the wash water is neutral. Place the wet polyacrylonitrile fiber in 60 mL of an ethylene glycol solution composed of 35% ethylenediamine and 12 mg of aluminum trichloride, and carry out catalytic amination at 110 °C for 5 h. After separation, under the conditions of a power of 40 kW and an acoustic intensity of 2.0 W / cm 2Under the conditions of 30 °C, first ultrasonically clean in water for 8 min, and then ultrasonically clean in ethanol for 5 min to obtain clean wet polyacrylonitrile-based chelating fibers. After drying at 60 °C for 1 h, dry polyacrylonitrile-based chelating fibers are prepared.
[0042] Through chemical analysis, the loading amounts of amino groups and amide groups on the prepared polyacrylonitrile-based chelating fibers are 6 mmol / g of dry fibers. Immerse 0.01 g of the above polyacrylonitrile-based chelating fibers separately in 150 mL of acidic solution containing 200 mg of In 3+ The equilibrium time is 8 min, indicating that the chelating fibers in this example have a high adsorption rate.
[0043] Comparative Example 1: Polyacrylonitrile-based chelating fibers were prepared by the conventional reflux hydrolysis and water bath amination method.
[0044] Take 1.0 g of polyacrylonitrile fiber, place it in 30 mL of 1% sodium hydroxide solution, and reflux and hydrolyze at 100 °C for 0.5 h. Separate the polyacrylonitrile fiber containing sodium carboxylate, and then wash it with water until the wash water is neutral. Immerse the above fiber in 35 mL of 0.5 mol / L sulfuric acid solution for 2 h, separate the polyacrylonitrile fiber containing carboxylic acid, and then wash it with water until the wash water is neutral. Place the wet polyacrylonitrile fiber in 60 mL of ethylene glycol solution containing 35% ethylenediamine, and carry out water bath amination at 90 °C for 5 h. After separation, wash it with water to obtain clean wet polyacrylonitrile-based chelating fibers. After drying at 60 °C for 1 h, dry polyacrylonitrile-based chelating fibers are prepared.
[0045] Through chemical analysis, the loading amounts of amino groups and amide groups on the polyacrylonitrile-based chelating fibers prepared in Comparative Example 1 are 1 mmol / g of dry fibers. Immerse 0.01 g of the above polyacrylonitrile-based chelating fibers separately in 150 mL of acidic solution containing 200 mg of In 3+ The equilibrium time is 30 min.
[0046] By comparing Example 2 and Comparative Example 1, it can be seen that the effect of Example 2 is better.
[0047] Example 3
[0048] Take 0.5 g of polyacrylonitrile fiber, with a power of 40 kW and an acoustic intensity of 2.0 W / cm 2Under room temperature conditions, first ultrasonically clean in water for 5 min, then ultrasonically clean in methanol for 5 min to obtain clean polyacrylonitrile fibers. At a microwave power of 500 W and a temperature of 95 °C, place the clean polyacrylonitrile fibers in 15 mL of 0.5% potassium hydroxide solution for catalytic hydrolysis for 1 h, separate to obtain polyacrylonitrile fibers containing sodium carboxylate, and then wash with water until the pH of the wash water is 7.0. Immerse the above hydrolyzed fibers in 15 mL of 1.0 mol / L hydrochloric acid solution for 2.5 h, separate to obtain polyacrylonitrile fibers containing carboxylic acid, and then wash with water until the pH value of the wash water is 7.0. Place the wet polyacrylonitrile fibers into 30 mL of an ethylene glycol solution composed of 40% tetraethylenepentamine and 5 mg of tin tetrachloride, and at 120 °C, carry out catalytic amination for 6 h. After separation, at a power of 25 kW and an acoustic intensity of 1.5 W / cm 2 Under room temperature conditions, first ultrasonically clean in water for 5 min, then ultrasonically clean in methanol for 8 min to obtain clean wet polyacrylonitrile-based chelating fibers. After drying at 50 °C for 2 h, dry polyacrylonitrile-based chelating fibers are prepared.
[0049] Through chemical analysis, the loading amounts of amino groups and amide groups on the prepared polyacrylonitrile-based chelating fibers are 8 mmol / g of dry fibers.
[0050] Immerse 0.01 g of polyacrylonitrile-based chelating fibers in 200 mL of an acidic solution containing 500 mg of Ga 3+ The time to reach equilibrium is only 5 min, indicating that the chelating fibers have a high adsorption rate.
[0051] Example 4
[0052] Take 1.5 g of polyacrylonitrile fibers, at a power of 30 kW and an acoustic intensity of 1.0 W / cm 2 Under room temperature conditions, first ultrasonically clean in water for 5 min, then ultrasonically clean in ethanol for 10 min to obtain clean polyacrylonitrile fibers. At a microwave power of 400 W and a temperature of 95 °C, place the clean polyacrylonitrile fibers in 40 mL of 1.0% sodium hydroxide solution for catalytic hydrolysis for 1 h, separate to obtain polyacrylonitrile fibers containing sodium carboxylate, and then wash with water until the pH of the wash water is 7.0. Immerse the above hydrolyzed fibers in 30 mL of 0.5 mol / L hydrochloric acid solution for 4 h, separate to obtain polyacrylonitrile fibers containing carboxylic acid, and then wash with water until the pH value of the wash water is close to 7.0. Place the wet polyacrylonitrile fibers into 60 mL of an ethylene glycol solution composed of 35% diethylenetriamine and 5 mg of cerium trichloride, and at 120 °C, carry out catalytic amination for 4 h. After separation, at a power of 35 kW and an acoustic intensity of 1.5 W / cm 2Under room temperature conditions, the polyacrylonitrile-based chelating fibers were ultrasonically cleaned in water for 5 minutes first, and then ultrasonically cleaned in methanol for 10 minutes to obtain clean wet polyacrylonitrile-based chelating fibers. After drying at 50 °C for 1.5 hours, dry polyacrylonitrile-based chelating fibers were prepared.
[0053] Through chemical analysis, the loading amounts of amide groups and amine groups on the prepared polyacrylonitrile-based chelating fibers were 10 mmol / g of dry fibers.
[0054] 0.01 g of polyacrylonitrile-based chelating fibers was immersed in 200 mL of sulfuric acid solution containing 400 mg of In 3+ The equilibrium time was only 6 minutes, indicating that the chelating fibers had a high adsorption rate.
Claims
1. A preparation method of polyacrylonitrile-based chelating fiber, characterized in that, The method comprises the following steps: (1) Alternately cleaning the surface of polyacrylonitrile fibers with two solvents, water and lower alcohol, by ultrasonic method to obtain clean polyacrylonitrile fibers; (2) Catalytically hydrolyzing the clean polyacrylonitrile fibers in an alkaline solution at 90 - 100 °C by microwave-assisted method to obtain polyacrylonitrile fibers containing carboxylate; the microwave power is 200 - 600 W, and the hydrolysis time is 0.5 - 1.0 h; (3) Washing the polyacrylonitrile-based fibers obtained in step (2) with pure water to wash away the alkali solution adhering to the fiber surface, and the washing end point is that the pH value of the washing water is close to 7.0; (4) Immersing the polyacrylonitrile-based fibers containing carboxylate obtained in step (3) in acid solution for 1 - 4 h, and then washing with pure water to wash away the acid solution adhering to the fiber surface, and the washing end point is that the pH value of the washing water is close to 7.0 to obtain polyacrylonitrile-based fibers containing carboxyl groups; (5) Catalytically aminating the carboxyl group-containing polyacrylonitrile-based fibers obtained in step (4) in a polyamine solution at 100 - 130 °C by solvothermal method to obtain crude polyacrylonitrile-based chelating fibers containing amino groups and amide groups; the solvent used is water, ethylene glycol or a mixed solvent composed of water and ethylene glycol, and the catalyst used is aluminum trichloride, tin tetrachloride, lanthanum chloride, cerium chloride; (6) Alternately cleaning the crude chelating fibers with two solvents, water and lower alcohol, by ultrasonic method, and then drying at 50 - 70 °C for 0.5 - 2.0 h to obtain dry polyacrylonitrile-based chelating fibers containing amide groups and amino groups.
2. The preparation method according to claim 1, characterized in that, The lower alcohol described in step (1) is methanol or ethanol.
3. The preparation method according to claim 1, characterized in that, In step (1), the ultrasonic frequency used in the ultrasonic method is 20 - 40 kHz, the average sound intensity is 1.0 - 2.0 W / cm 2 , the temperature is from room temperature to 40 °C, and the time is 5 - 10 min.
4. The preparation method according to claim 1, characterized in that, The alkali used in step (2) is one of sodium hydroxide, potassium hydroxide, and sodium carbonate; when sodium carbonate is selected, the alkali solution concentration is 2.0 wt% - 10 wt%; when sodium hydroxide is selected, the alkali solution concentration is 0.5 wt% - 2.0 wt%; when potassium hydroxide is selected, the alkali solution concentration is 0.5 wt% - 2.0 wt%.
5. The preparation method according to claim 1, wherein The solid-liquid ratio of the polyacrylonitrile fibers to the alkali solution in step (2) is 1 g: 20 - 40 mL.
6. The preparation method according to claim 1, characterized in that, The acid used for the acid solution in step (4) is one of hydrochloric acid and sulfuric acid; when hydrochloric acid is selected, the hydrochloric acid concentration is 0.1 - 1.0 mol / L; when sulfuric acid is selected, the sulfuric acid concentration is 0.05 - 0.5 mol / L; The solid-liquid ratio of the polyacrylonitrile-based fibers to the acid solution is 1 g: 20 - 40 mL.
7. The preparation method according to claim 1, wherein The polyamine used in step (5) is one of ethylenediamine, diethylenetriamine, and triethylenetetramine; the volume concentration of the polyamine in the polyamine solution is 20 vol% - 50 vol%, and the solid-liquid ratio of the polyacrylonitrile-based fibers to the polyamine solution is 1 g: 20 - 80 mL; the dosage of the catalyst described in step (5) is 0.25 wt% - 5.0 wt% of the fiber amount, and the reaction time is 2 - 6 h.
8. The preparation method according to claim 1, wherein The lower alcohol in step (6) is methanol or ethanol; the ultrasonic frequency used is 20 - 40 kHz, the average sound intensity is 1.0 - 2.0 W / cm 2 , the temperature is from room temperature to 40 °C, and the time is 5 - 10 min.
9. The polyacrylonitrile-based chelating fiber obtained by the preparation method according to any one of claims 1-8, characterized in that, Using polyacrylonitrile fibers as the backbone, the functional groups coordinated with metal ions on the backbone are amino groups and amide groups, and the coordination atom nitrogen in the functional groups is combined with carbon atoms in the form of covalent bonds, wherein the loading amounts of the amide groups and amino groups are 2 - 10 mmol / g of dry polyacrylonitrile fibers.
10. Application of the polyacrylonitrile-based chelating fibers obtained by the preparation method according to any one of claims 1 - 8 in the adsorption, separation or enrichment of gallium and indium ions.