Preparation method of functionalized halloysite nanotube / polyaniline composite film

Abstract

The invention discloses a preparation method of a functionalized halloysite nanotube / polyaniline composite membrane, which comprises the following steps: ultrasonically dispersing halloysite nanotubes in toluene, adding KH550, reacting, carrying out suction filtration, washing and drying to obtain KH550 modified halloysite nanotubes, and drying to obtain the functionalized halloysite nanotube / polyaniline composite membrane. Then carrying out a ring-opening reaction on epoxy chloropropane and the KH550 modified halloysite nanotube to obtain a functionalized halloysite nanotube containing an imino group, a hydroxyl group and a chlorine group; the preparation method comprises the following steps: carrying out substitution reaction on amino and chlorine, taking a polyamine compound as a cross-linking agent to realize cross-linking among functionalized halloysite nanotubes, carrying out suction filtration to form a film, washing, and drying to obtain a functionalized halloysite nanotube film with the gram weight of not more than 15g / m < 2 >; and performing in-situ polymerization of polyaniline in the functionalized halloysite nanotube film, and performing in-situ crosslinking to obtain the functionalized halloysite nanotube / polyaniline composite film. The adsorption performance of the halloysite nanotubes on heavy metal ions is improved, and the obtained composite membrane is easy to recover.

Description

Technical Field

[0001] The present invention relates to the technical field of polyaniline composite films, and particularly to a preparation method of a functionalized halloysite nanotube / polyaniline composite film. Background Art

[0002] For the removal of heavy metal ions in industrial wastewater, various methods have been developed currently, including but not limited to flocculation treatment, chemical precipitation method, membrane separation technology, ion exchange process, and adsorption technology, etc. However, traditional adsorption media generally show the deficiencies of limited heavy metal ion removal ability and relatively high cost. As a natural mineral material with natural occurrence, abundant reserves, non-toxic and environmentally friendly, halloysite nanotubes have broad application potential in the field of heavy metal wastewater treatment due to their significant specific surface area advantage, strong adsorption performance, and high adsorption rate. However, the nano-scale particle size characteristics make halloysite nanotubes easily form a stable suspension system in water, which not only increases the difficulty of effective separation and recovery from water bodies, but also affects its overall efficiency in industrial practice. In addition, the limited number of functional groups on the surface of halloysite nanotubes leads to its relatively low adsorption capacity for heavy metal ions. Summary of the Invention

[0003] Aiming at the above-mentioned defects of the prior art, the present invention provides a preparation method of a functionalized halloysite nanotube / polyaniline composite film to improve the adsorption performance of halloysite nanotubes for heavy metal ions and ensure its easy recovery.

[0004] The technical solution of the present invention is as follows: A preparation method of a functionalized halloysite nanotube / polyaniline composite film includes the following steps: (1) Halloysite nanotubes are ultrasonically dispersed in toluene and KH550 is added. After reaction, filtration, washing, and drying are carried out to obtain KH550-modified halloysite nanotubes. Then, ring-opening reaction is carried out between epichlorohydrin and KH550-modified halloysite nanotubes to obtain functionalized halloysite nanotubes containing imino, hydroxyl, and chloro groups; (2) Using the substitution reaction of amino and chloro, a polyamine compound is used as a cross-linking agent to achieve cross-linking between functionalized halloysite nanotubes, and then filtration is carried out to form a film. After washing and drying, a functionalized halloysite nanotube film with a grammage not greater than 15 g / m 2 is obtained; (3) Polyaniline is in-situ polymerized and in-situ cross-linked in the functionalized halloysite nanotube film to obtain a functionalized halloysite nanotube / polyaniline composite film.

[0005] Further, in the step (1), the added mass of KH550 is 1 to 2 times that of halloysite nanotubes, and after adding KH550, the reaction is carried out at 80 to 110 °C for 10 to 15 h.

[0006] Further, the specific operation of step (1) is to ultrasonically disperse KH550-modified halloysite nanotubes in an aqueous sodium carbonate solution, then add epichlorohydrin for ring-opening reaction, followed by suction filtration, washing, and drying. The dosage ratio of KH550-modified halloysite nanotubes to epichlorohydrin is 1 g:(0.01 - 0.03) L, and the concentration of the aqueous sodium carbonate solution is 1 - 5 wt%.

[0007] Further, in step (1), the ring-opening reaction is carried out under stirring at 30 - 70 °C for 2 - 5 h.

[0008] Further, the specific operation of step (2) is to ultrasonically disperse functionalized halloysite nanotubes in acetonitrile. Under nitrogen protection, a polyamino compound and an acid-binding agent are added for cross-linking reaction. The mass ratio of functionalized halloysite nanotubes, polyamino compound, and acid-binding agent is 1:(0.5 - 2):(1 - 2).

[0009] Further, in step (2), the cross-linking reaction is carried out under stirring at 60 - 70 °C for 8 - 12 h.

[0010] Further, the acid-binding agent is pyridine or triethylamine, and the polyamino compound is one of triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0011] Further, in step (3), the functionalized halloysite nanotube membrane is immersed in an aniline monomer solution with a concentration of 0.05 - 0.15 mol / L at 3 - 5 °C for 15 - 35 min and then taken out, and then immersed in an oxidant solution for 6 - 12 min. After pouring out the excess oxidant solution, the reaction continues for 5 - 9 h and then dries at room temperature to obtain a composite membrane, followed by in-situ cross-linking.

[0012] Further, the in-situ cross-linking is to immerse the prepared composite membrane in a cross-linking agent solution at 50 - 70 °C for 1 - 2 h, followed by washing and drying to obtain a functionalized halloysite nanotube / polyaniline composite membrane.

[0013] Further, the cross-linking agent solution is an N , N N,N'-dimethylformamide solution of ethylenediaminetetraacetic dianhydride with a concentration of 8 - 10 mg / mL.

[0014] First, epichlorohydrin was used as a modifier. By means of the ring-opening reaction of the epoxy group with the amino group of KH550-modified halloysite nanotubes, a large number of imino, hydroxyl, and chloro functional groups were introduced onto the surface of the halloysite nanotubes, effectively enhancing the functionality of the halloysite nanotubes. Subsequently, polyamine compounds were used as cross-linking agents. Through the substitution reaction between chlorine atoms and amino groups, firm cross-linking between the halloysite nanotubes was achieved, effectively enhancing the structural stability of the membrane. Meanwhile, a large number of imine groups were introduced, further strengthening its adsorption capacity for heavy metal ions. On this basis, polyaniline was in-situ polymerized inside the functionalized halloysite nanotube membrane in this invention, which further improved the adsorption capacity of the composite membrane. Finally, through the reaction of anhydride with amino group, ethylenediaminetetraacetic dianhydride was selected as the cross-linking agent to achieve effective cross-linking between the functionalized halloysite nanotubes and polyaniline. This step not only further consolidated the structural stability of the composite membrane, but also optimized the pore structure of the membrane through the cross-linking process, and at the same time introduced more N and O atoms with lone pair electrons that have excellent adsorption properties for heavy metals, thus obtaining a halloysite nanotube / polyaniline composite membrane with both excellent structural stability and excellent adsorption properties.

[0015] The advantages of this invention compared with the prior art are as follows: The composite membrane prepared in this invention not only realizes the fusion and synergistic enhancement of the adsorption properties of halloysite nanotubes and polyaniline, but also has a rich pore structure and numerous atoms and functional groups with excellent adsorption properties for heavy metal ions. Therefore, it has an excellent adsorption capacity for heavy metal ions.

[0016] Through the multiple modification strategies of cross-linking, compounding, and re-cross-linking, this invention significantly enhances the structural stability of the composite membrane, overcomes the problem that halloysite nanomaterials are not easily separated and recovered from water bodies, and greatly improves the practical value and economic benefits of the materials. Description of the Drawings

[0017] Figure 1 It is the infrared spectrum of the original halloysite nanotubes and the polyamine compound-modified functionalized halloysite nanotubes prepared in Example 1.

[0018] Figure 2 It is the SEM image of the composite membrane prepared in Example 1. Detailed Embodiments

[0019] The present invention will be further described below in conjunction with the embodiments, but it is not intended to limit the present invention.

[0020] Example 1

[0021] A preparation method of a functionalized halloysite nanotube / polyaniline composite membrane includes the following steps: (1) Preparation of functionalized halloysite nanotubes 1 g of halloysite nanotubes (Xianfeng Nano, CAS No.: 1332 - 58 - 7, product number: 103763) was ultrasonically dispersed in toluene, then 1 g of KH550 was added, and the mixture was stirred and reacted at 80 °C for 15 h. After filtration, thorough washing, and drying, KH550 - modified halloysite nanotubes were obtained.

[0022] 1 g of the prepared KH550 - modified halloysite nanotubes was ultrasonically dispersed in an aqueous sodium carbonate solution with a concentration of 1 wt%, then 10 mL of epichlorohydrin was added, and the mixture was stirred and reacted at 30 °C for 5 h. After the reaction, filtration, thorough washing with deionized water, and drying, functionalized halloysite nanotubes rich in imino, hydroxyl, and chloro groups were obtained.

[0023] (2) Preparation of functionalized halloysite nanotube membranes 1 g of the prepared functionalized halloysite nanotubes was ultrasonically dispersed in acetonitrile. Under nitrogen protection, 0.5 g of triethylenetetramine and 1 g of pyridine were added, and the mixture was stirred and reacted at 60 °C for 12 h. After cooling to room temperature, solvent was added to make the reaction system reach 2000 mL. 52.3 mL of the reaction solution was taken for filtration, washed repeatedly with deionized water, and after drying, the sample membrane was peeled off from the filter membrane to obtain a functionalized halloysite nanotube membrane with a diameter of 10 cm and a grammage of 5 g / m 2 The infrared spectrum of which is as Figure 1 shown. It can be seen that the original halloysite nanotubes showed stretching vibration and deformation vibration absorption peaks of O - H in the Al - OH group at 3695 cm -1 and 3621 cm -1 respectively, a characteristic absorption peak of the Si - O - Si bond at 1031 cm -1 and a bending vibration peak of Al - OH at 912 cm -1 . These are all typical absorption peaks of halloysite. The functionalized halloysite nanotubes cross - linked and modified with polyamine compounds showed characteristic absorption peaks of halloysite at 1031 cm -1 and 912 cm -1 , but the absorption peaks at 3695 cm -1 and 3621 cm -1 disappeared. At the same time, a strong absorption peak jointly caused by imino and hydroxyl groups appeared near 3428 cm -1 . This is because after functional modification, most of the Al - OH on the surface of halloysite nanotubes participated in the reaction, and the absorption peaks of the very small amount of unreacted Al - OH were weak and masked by the strong peak of imino. In addition, after modification, characteristic absorption peaks of - CH -1 appeared at 2925 cm -1 and 2853 cm 2 , and a characteristic absorption peak at 1630 cm -1The bending vibration peak of N-H appears.

[0024] (3)Preparation of Functionalized Halloysite Nanotube / Polyaniline Composite Membrane Dissolve aniline monomer in hydrochloric acid (1 mol / L) solution to obtain an aniline monomer solution with a concentration of 0.05 mol / L. Then immerse the prepared functionalized halloysite nanotube membrane in the prepared aniline monomer solution at 3 °C for 35 min. Take out the functional membrane and immerse it in ammonium persulfate solution (0.1 mol / L) at 3 °C for 12 min. Pour out the excess solution, and the membrane continues to react at 3 °C for 9 h, and then dry at room temperature to obtain the composite membrane.

[0025] Immerse the prepared composite membrane in a solution of ethylenediaminetetraacetic dianhydride with a concentration of 8 mg / ml at 50 °C N , N -dimethylformamide solution for 2 h. Wash thoroughly and dry to obtain the functionalized halloysite nanotube / polyaniline composite membrane, and its SEM image is as Figure 2 shown, and it can be seen that the prepared membrane has many pore structures.

[0026] The adsorption performance test experiment of a functionalized halloysite nanotube / polyaniline composite membrane in Example 1 is as follows: Prepare 100 mL of an aqueous solution with a lead ion (lead nitrate as the reagent) concentration of 100 mg / L in a flask. After adjusting the pH of the solution to 7 with 0.1 M NaOH, add the prepared functionalized halloysite nanotube / polyaniline composite membrane, and then adsorb at 30 °C in a constant temperature shaker at a rotation speed of 200 rpm for 3 h. After adsorption, take the supernatant and use ICP-OES to measure the concentration of lead ions in the supernatant. Calculate the adsorption capacity of the adsorbent for lead ions through the following formula ( Q , mg / g), and the results are listed in Table 1.

[0027] Q = ( C 0 - C t ) V / M Q is the adsorption capacity (mg / g); C 0 is the initial concentration of heavy metal ions (mg / L); C t is the concentration of heavy metal ions after adsorption (mg / L); V is the volume of the solution (L); M is the mass of the adsorbent (g).

[0028] Example 2

[0029] A preparation method of a functionalized halloysite nanotube / polyaniline composite membrane, comprising the following steps: (1) Preparation of functionalized halloysite nanotubes Disperse 1 g of halloysite nanotubes (Xianfeng Nano, CAS No.: 1332-58-7, product number: 103763) ultrasonically in toluene, then add 1.5 g of KH550, stir and react at 95 °C for 12.5 h, carry out suction filtration, wash thoroughly, and dry to obtain KH550-modified halloysite nanotubes.

[0030] Disperse 1 g of the prepared KH550-modified halloysite nanotubes ultrasonically in an aqueous sodium carbonate solution with a concentration of 3 wt%, then add 20 mL of epichlorohydrin, stir and react at 50 °C for 3.5 h, after the reaction, carry out suction filtration, wash thoroughly with deionized water, and dry to obtain functionalized halloysite nanotubes rich in imino, hydroxyl and chloro groups.

[0031] (2) Preparation of functionalized halloysite nanotube membranes Disperse 1 g of the prepared functionalized halloysite nanotubes ultrasonically in acetonitrile, under nitrogen protection, add 1.25 g of tetraethylenepentamine and 1.5 g of triethylamine, stir and react at 65 °C for 10 h, after cooling to room temperature, add solvent to make the reaction system reach 2000 mL, take 69.8 mL of the reaction solution for suction filtration, wash repeatedly with deionized water, and after drying, peel the sample membrane off the filter membrane to obtain a functionalized halloysite nanotube membrane with a diameter of 10 cm and a grammage of 10 g / m 2 2.

[0032] (3) Preparation of functionalized halloysite nanotube / polyaniline composite membranes Dissolve aniline monomer in hydrochloric acid (1 mol / L) solution to obtain an aniline monomer solution with a concentration of 0.1 mol / L. Then immerse the prepared functionalized halloysite nanotube membrane in the prepared aniline monomer solution at 4 °C for 25 min. Take out the functional membrane and immerse it in ammonium persulfate solution (0.15 mol / L) at 4 °C for 9 min, pour out the excess solution, and the membrane continues to react at 4 °C for 7 h, and dry at room temperature to obtain the composite membrane.

[0033] Immerse the prepared composite membrane in a N , N N,N'-dimethylformamide solution with a concentration of 9 mg / ml at 60 °C for 1.5 h. Wash thoroughly and dry to obtain a functionalized halloysite nanotube-based composite membrane, and its adsorption capacity for lead ions is measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0034] Example 3

[0035] A preparation method of a functionalized halloysite nanotube / polyaniline composite membrane, comprising the following steps: (1) Preparation of functionalized halloysite nanotubes Ultrasonically disperse 1 g of halloysite nanotubes (Xianfeng Nano, CAS No.: 1332-58-7, product number: 103763) in toluene, then add 2 g of KH550, and stir and react at 110 °C for 10 h. Perform suction filtration, wash thoroughly, and dry to obtain KH550-modified halloysite nanotubes.

[0036] Ultrasonically disperse 1 g of the obtained KH550-modified halloysite nanotubes in an aqueous sodium carbonate solution with a concentration of 5 wt%, then add 30 mL of epichlorohydrin, and stir and react at 70 °C for 2 h. After the reaction, perform suction filtration, wash thoroughly with deionized water, and dry to obtain functionalized halloysite nanotubes rich in imino, hydroxyl, and chloro groups.

[0037] (2) Preparation of functionalized halloysite nanotube membranes Ultrasonically disperse 1 g of the obtained functionalized halloysite nanotubes in acetonitrile. Under nitrogen protection, add 2 g of pentaethylenehexamine and 2 g of pyridine, and stir and react at 70 °C for 8 h. After cooling to room temperature, add solvent to make the reaction system reach 2000 mL. Take 78.5 mL of the reaction solution for suction filtration, wash repeatedly with deionized water, and after drying, peel the sample membrane from the filter membrane to obtain a functionalized halloysite nanotube membrane with a diameter of 10 cm and a grammage of 15 g / m 2 2.

[0038] (3) Preparation of functionalized halloysite nanotube / polyaniline composite membranes Dissolve aniline monomer in hydrochloric acid (1 mol / L) solution to obtain an aniline monomer solution with a concentration of 0.15 mol / L. Then immerse the obtained functionalized halloysite nanotube membrane in the prepared aniline monomer solution at 5 °C for 15 min. Take out the functional membrane and immerse it in ammonium persulfate solution (0.2 mol / L) at 5 °C for 6 min. Pour out the excess solution, and continue to react the membrane at 5 °C for 5 h, and dry at room temperature to obtain a composite membrane.

[0039] Immerse the obtained composite membrane in a N , N N,N'-dimethylformamide solution with a concentration of 10 mg / ml at 70 °C for 1 h. Wash thoroughly and dry to obtain a functionalized halloysite nanotube-based composite membrane, and its adsorption capacity for lead ions is measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0040] Example 4

[0041] The difference between this example and Example 1 is that: in step (2) of this example, 104.6 ml of the cross-linking reaction solution was taken for suction filtration to form a film, and a functionalized halloysite nanotube film with a diameter of 10 cm and a grammage of 10 g / m 2 was obtained. The remaining steps were the same as those in Example 1. The adsorption capacity of the prepared composite film for lead ions was measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0042] Example 5

[0043] The difference between this example and Example 1 is that: in step (2) of this example, 157 ml of the cross-linking reaction solution was taken for suction filtration to form a film, and a functionalized halloysite nanotube film with a diameter of 10 cm and a grammage of 15 g / m 2 was obtained. The remaining steps were the same as those in Example 1. The adsorption capacity of the prepared composite film for lead ions was measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0044] Comparative Example 1 1 g of halloysite nanotubes (Xianfeng Nano, CAS No.: 1332-58-7, product number: 103763) was ultrasonically dispersed in 2000 mL of N , N N,N-dimethylformamide. After ultrasonic dispersion was uniform, 78.5 mL of the reaction solution was taken for suction filtration, washed repeatedly with deionized water, and after drying, the sample film was peeled off from the filter membrane to obtain a pure halloysite nanotube film with a diameter of 10 cm and a grammage of 5 g / m 2 . Its adsorption capacity for lead ions was measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0045] Comparative Example 2 The functionalized halloysite nanotubes were prepared according to step (1) in Example 1, and then 1 g of the functionalized halloysite nanotubes was ultrasonically dispersed in 2000 mL of N , N N,N-dimethylformamide. After ultrasonic dispersion was uniform, 78.5 mL of the reaction solution was taken for suction filtration, washed repeatedly with deionized water, and after drying, the sample film was peeled off from the filter membrane to obtain an uncrosslinked functionalized halloysite nanotube film with a diameter of 10 cm and a grammage of 5 g / m 2 . Its adsorption capacity for lead ions was measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0046] Comparative Example 3 The cross-linked functionalized halloysite nanotube film was prepared according to steps (1) and (2) in Example 1, but step (3) was not carried out. The adsorption capacity of the functionalized halloysite nanotube film for lead ions was measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0047] Comparative Example 4 The functionalized halloysite nanotube / polyaniline composite film was prepared according to steps (1), (2), and (3) in Example 1. However, in step (3), the composite film was not subjected to in-situ crosslinking treatment. The adsorption capacity of the composite film for lead ions was measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0048] Table 1 Adsorption amounts of the films prepared in Examples 1-5 and Comparative Examples 1-4 for lead ions

[0049] It can be seen from the above results that in the composite films prepared in the examples of the present invention, effective crosslinks are formed between halloysite nanotubes and between halloysite nanotubes and polyaniline molecular chains, realizing the strong combination and synergistic effect in adsorption performance between them. Moreover, numerous atoms and functional groups with excellent adsorption performance for heavy metal ions are introduced during the functionalization and two crosslinking modification processes. At the same time, the double crosslinking process endows the composite film with a rich pore structure. Relying on these three advantages, the prepared composite film exhibits excellent adsorption capacity for lead ions, and its adsorption amount for lead ions can reach 351 mg / g. In contrast, the halloysite nanotube films in Comparative Example 1 and Comparative Example 2 lack rich functional groups, have no synergistic adsorption effect, and have no developed pore structure; although the halloysite film in Comparative Example 3 contains more functional groups, it has no synergistic adsorption effect. Although the synergistic adsorption of halloysite and polyaniline can be exerted in Comparative Example 4, the importance of in-situ crosslinking treatment of the composite film is ignored. Therefore, the adsorption capacities of the adsorption materials prepared in the comparative examples for lead ions cannot be compared with those of the functionalized halloysite nanotube / composite films prepared in the examples.

[0050] It should be noted that although theoretically increasing the mass of the film can provide more adsorption sites, this also means that the film will become thicker (when the diameter remains unchanged). However, the increase in film thickness will hinder the penetration of metal ions into the interior of the film, resulting in a decrease in mass transfer efficiency, and further affecting the total amount of metal ions adsorbed. Therefore, when the film thickness exceeds a certain critical value, the actual increase in adsorption amount will no longer conform to the expectation and may even decrease, as shown by the results of Examples 1, 4, and 5.

Claims

1. A method for preparing a functionalized halloysite nanotube / polyaniline composite film, characterized in that: The following steps are involved: (1) Halloysite nanotubes are ultrasonically dispersed in toluene and KH550 is added. After the reaction, the mixture is filtered, washed and dried to obtain KH550-modified halloysite nanotubes. Then, epichlorohydrin is used to react with the KH550-modified halloysite nanotubes to undergo a ring-opening reaction to obtain functionalized halloysite nanotubes containing imino groups, hydroxyl groups and chlorine groups. (2) Using the substitution reaction between amino groups and chlorine, polyamine compounds are used as cross-linking agents to achieve cross-linking between functionalized halloysite nanotubes, and then filtration is performed to form a membrane, and after washing and drying, a weight of no more than 15 g / m 2 Functionalized halloysite nanotube membrane; (3) In situ polymerizing polyaniline in the functionalized halloysite nanotube membrane and performing in situ crosslinking to obtain a functionalized halloysite nanotube / polyaniline composite membrane.

2. The method for preparing a functionalized halloysite nanotube / polyaniline composite film according to claim 1, characterized in that: In the step (1), the mass of KH550 added is 1 to 2 times that of the halloysite nanotubes, and after adding KH550, the reaction is carried out at 80 to 110° C. for 10 to 15 hours.

3. The method for preparing a functionalized halloysite nanotube / polyaniline composite film according to claim 1, characterized in that: The step (1) specifically comprises ultrasonically dispersing the KH550 modified halloysite nanotubes in a sodium carbonate aqueous solution, then adding epichlorohydrin to carry out a ring-opening reaction, and then filtering, washing, and drying, wherein the amount ratio of the KH550 modified halloysite nanotubes to epichlorohydrin is 1 g: (0.01-0.03) L, and the concentration of the sodium carbonate aqueous solution is 1-5 wt%.

4. The method for preparing a functionalized halloysite nanotube / polyaniline composite film according to claim 1, characterized in that: The ring-opening reaction in step (1) is carried out by stirring at 30-70° C. for 2-5 hours.

5. The method for preparing a functionalized halloysite nanotube / polyaniline composite film according to claim 1, characterized in that: The step (2) specifically comprises ultrasonically dispersing the functionalized halloysite nanotubes in acetonitrile, adding a polyamino compound and an acid binding agent under nitrogen protection, and performing a cross-linking reaction, wherein the mass ratio of the functionalized halloysite nanotubes, the polyamino compound and the acid binding agent is 1:(0.5-2):(1-2).

6. The method for preparing a functionalized halloysite nanotube / polyaniline composite film according to claim 5, characterized in that: The cross-linking reaction in step (2) is stirred at 60-70° C. for 8-12 hours.

7. The method for preparing a functionalized halloysite nanotube / polyaniline composite film according to claim 5, characterized in that: The acid binding agent is pyridine or triethylamine, and the polyamino compound is one of triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine.

8. The method for preparing a functionalized halloysite nanotube / polyaniline composite film according to claim 1, characterized in that: The step (3) is to soak the functionalized halloysite nanotube membrane in a 0.05-0.15 mol / L aniline monomer solution at 3-5°C for 15-35 minutes, then take it out, soak it in an oxidant solution for 6-12 minutes, pour out the excess oxidant solution, continue the reaction for 5-9 hours, dry it at room temperature to obtain a composite membrane, and then perform in-situ crosslinking.

9. The method for preparing a functionalized halloysite nanotube / polyaniline composite film according to claim 8, characterized in that: The in-situ crosslinking is to immerse the prepared composite membrane in a crosslinking agent solution at 50-70° C. for 1-2 hours, and then wash and dry to obtain a functionalized halloysite nanotube / polyaniline composite membrane.

10. The method for preparing a functionalized halloysite nanotube / polyaniline composite film according to claim 9, characterized in that: The cross-linking agent solution is ethylenediaminetetraacetic acid dianhydride with a concentration of 8 to 10 mg / mL. N , N -Dimethylformamide solution.

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