Preparation method of functionalized halloysite nanotube / polyaniline composite film

Abstract

The present invention discloses a preparation method of a functionalized halloysite nanotube / polyaniline composite film, comprising the steps of: ultrasonically dispersing halloysite nanotubes in toluene and adding KH550, filtering by suction, washing and drying after reaction to obtain KH550-modified halloysite nanotubes, and then carrying out a ring-opening reaction between epichlorohydrin and the KH550-modified halloysite nanotubes to obtain functionalized halloysite nanotubes containing imino groups, hydroxyl groups and chlorine groups; utilizing the substitution reaction between amino groups and chlorine, using polyamine compounds as cross-linking agents to achieve cross-linking between the functionalized halloysite nanotubes, and then filtering by suction to form a film, washing and drying to obtain a functionalized halloysite nanotube film with a grammage not greater than 15 g / m<supgt;2< / supgt>; in-situ polymerizing polyaniline in the functionalized halloysite nanotube film and carrying out in-situ cross-linking to obtain a functionalized halloysite nanotube / polyaniline composite film. The present invention improves the adsorption performance of halloysite nanotubes for heavy metal ions and the obtained composite film is easy to recycle.

Description

Technical Field

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

[0002] For the removal of heavy metal ions in industrial wastewater, a variety of 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 nanoscale particle size characteristics make halloysite nanotubes easy to 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 membrane, which improves the adsorption performance of halloysite nanotubes for heavy metal ions and ensures its easy recovery.

[0004] The technical solution of the present invention is as follows: A preparation method of a functionalized halloysite nanotube / polyaniline composite membrane, comprising the following steps:

[0005] (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;

[0006] (2) Using the substitution reaction of amino and chloro, a polyamine compound is used as a cross-linking agent to realize the cross-linking between functionalized halloysite nanotubes, and then filtration is carried out to form a membrane. After washing and drying, a functionalized halloysite nanotube membrane with a grammage not greater than 15 g / m 2 is obtained;

[0007] (3) Polyaniline is in-situ polymerized and in-situ cross-linked in the functionalized halloysite nanotube membrane to obtain a functionalized halloysite nanotube / polyaniline composite membrane.

[0008] 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.

[0009] Further, the step (1) specifically is to ultrasonically disperse KH550-modified halloysite nanotubes in an aqueous sodium carbonate solution, then add epichlorohydrin for ring-opening reaction and carry out 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 to 5 wt%.

[0010] Further, in the step (1), the ring-opening reaction is carried out under stirring at 30 to 70 °C for 2 to 5 h.

[0011] Further, the step (2) specifically is to ultrasonically disperse functionalized halloysite nanotubes in acetonitrile, and under nitrogen protection, add a polyamino compound and a deacidifying agent for cross-linking reaction. The mass ratio of functionalized halloysite nanotubes, polyamino compound, and deacidifying agent is 1:(0.5~2):(1~2).

[0012] Further, in the step (2), the cross-linking reaction is carried out under stirring at 60 to 70 °C for 8 to 12 h.

[0013] Further, the deacidifying agent is pyridine or triethylamine, and the polyamino compound is one of triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0014] Further, in the step (3), the functionalized halloysite nanotube membrane is immersed in an aniline monomer solution with a concentration of 0.05 to 0.15 mol / L at 3 to 5 °C for 15 to 35 min and then taken out, and then immersed in an oxidant solution for 6 to 12 min and the excess oxidant solution is poured out, and the reaction continues for 5 to 9 h and then dried at room temperature to obtain a composite membrane, and then in-situ cross-linking is carried out.

[0015] Further, the in-situ cross-linking is to immerse the obtained composite membrane in a cross-linking agent solution at 50 to 70 °C for 1 to 2 h and then wash and dry to obtain a functionalized halloysite nanotube / polyaniline composite membrane.

[0016] Further, the cross-linking agent solution is an N , N N,N'-dimethylformamide solution of ethylenediaminetetraacetic dianhydride with a concentration of 8 to 10 mg / mL.

[0017] First, using epichlorohydrin as a modifier, through 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, and through the substitution reaction between chlorine atoms and amino groups, strong cross-linking between the halloysite nanotubes was achieved, effectively enhancing the structural stability of the membrane. At the same time, 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 pairs of 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 performance.

[0018] The advantages of this invention compared with the prior art are as follows:

[0019] The composite membrane prepared in this invention not only realizes the fusion and synergistic enhancement of the adsorption performance of halloysite nanotubes and polyaniline, but also has a rich pore structure and numerous atoms and functional groups with excellent adsorption performance for heavy metal ions. Therefore, it has an excellent adsorption capacity for heavy metal ions.

[0020] Through 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

[0021] Figure 1 It is the infrared spectrum diagram of the original halloysite nanotubes and the polyamine compound-modified functionalized halloysite nanotubes prepared in Example 1.

[0022] Figure 2 It is the SEM diagram of the composite membrane prepared in Example 1. Detailed Embodiments

[0023] The following further illustrates the present invention with reference to examples, but it is not intended to limit the present invention.

[0024] Example 1

[0025] A preparation method of a functionalized halloysite nanotube / polyaniline composite membrane includes the following steps:

[0026] (1) Preparation of functionalized halloysite nanotubes

[0027] Disperse 1 g of halloysite nanotubes (Xianfeng Nano, CAS No.: 1332 - 58 - 7, product number: 103763) ultrasonically in toluene, then add 1 g of KH550, stir and react at 80 °C for 15 h, carry out suction filtration, wash thoroughly, and dry to obtain KH550 - modified halloysite nanotubes.

[0028] Disperse 1 g of the prepared KH550 - modified halloysite nanotubes ultrasonically in an aqueous sodium carbonate solution with a concentration of 1 wt%, then add 10 mL of epichlorohydrin, stir and react at 30 °C for 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.

[0029] (2) Preparation of functionalized halloysite nanotube membranes

[0030] Disperse 1 g of the prepared functionalized halloysite nanotubes ultrasonically in acetonitrile. Under nitrogen protection, add 0.5 g of triethylenetetramine and 1 g of pyridine, stir and react at 60 °C for 12 h. After cooling to room temperature, add solvent to make the reaction system reach 2000 mL. Take 52.3 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 5 g / m 2 The infrared spectrum of which is as shown in Figure 1 As shown, it can be seen that the original halloysite nanotubes show 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 show characteristic absorption peaks of halloysite at 1031 cm -1 , 912 cm -1 , but the absorption peaks at 3695 cm -1 and 3621 cm -1 disappear. At the same time, a strong absorption peak jointly caused by imino and hydroxyl appears near 3428 cm -1 . This is because after functional modification, most of the Al - OH on the surface of halloysite nanotubes participate in the reaction, and the absorption peaks of the extremely small amount of unreacted Al - OH are weak and masked by the strong peak of imino. In addition, after modification, at 2925 cm -1 and 2853 cm -1The characteristic absorption peak of -CH2- appeared at 1630 cm -1 The bending vibration peak of N-H appeared.

[0031] (3)Preparation of functionalized halloysite nanotube / polyaniline composite film

[0032] 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 film in the prepared aniline monomer solution at 3°C for 35 min. Take out the functional film and immerse it in ammonium persulfate solution (0.1 mol / L) at 3°C for 12 min. Pour out the excess solution, and the film continues to react at 3°C for 9 h and then is dried at room temperature to obtain the composite film.

[0033] Immerse the obtained composite film in a solution of ethylenediaminetetraacetic dianhydride with a concentration of 8 mg / ml at 50°C N , N -dimethylformamide solution for 2 h. After thorough washing and drying, the functionalized halloysite nanotube / polyaniline composite film is obtained. Its SEM image is as Figure 2 shown, and it can be seen that the prepared film has many pore structures.

[0034] The adsorption performance test experiment of a kind of functionalized halloysite nanotube / polyaniline composite film in Example 1 is as follows:

[0035] 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 film, and then adsorb it in a constant temperature shaker at 30°C 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 amount of the adsorbent material for lead ions through the following formula ( Q , mg / g), and the results are listed in Table 1.

[0036] Q = ( C 0 - C t ) V / M

[0037] Q is the adsorption amount (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); Mis the mass (g) of the adsorbent.

[0038] Example 2

[0039] A method for preparing a functionalized halloysite nanotube / polyaniline composite membrane, comprising the following steps:

[0040] (1) Preparation of functionalized halloysite nanotubes

[0041] 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, perform suction filtration, wash thoroughly, and dry to obtain KH550-modified halloysite nanotubes.

[0042] 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, perform suction filtration, wash thoroughly with deionized water, and dry to obtain functionalized halloysite nanotubes rich in imino, hydroxyl, and chloro groups.

[0043] (2) Preparation of functionalized halloysite nanotube membranes

[0044] 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 from 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.

[0045] (3) Preparation of functionalized halloysite nanotube / polyaniline composite membranes

[0046] 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 let the membrane continue to react at 4 °C for 7 h, then dry at room temperature to obtain the composite membrane.

[0047] Immerse the prepared composite membrane in N , NSoak in N,N-dimethylformamide solution for 1.5 h. After thorough washing and drying, a functionalized halloysite nanotube-based composite membrane is obtained. The adsorption capacity of the composite membrane 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.

[0048] Example 3

[0049] A preparation method of a functionalized halloysite nanotube / polyaniline composite membrane includes the following steps:

[0050] (1) Preparation of functionalized halloysite nanotubes

[0051] Disperse 1 g of halloysite nanotubes (Xianfeng Nano, CAS No.: 1332-58-7, product number: 103763) in toluene by ultrasonic treatment, then add 2 g of KH550, and stir and react at 110 °C for 10 h. Carry out suction filtration, thorough washing, and drying to obtain KH550-modified halloysite nanotubes.

[0052] 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, carry out suction filtration, wash thoroughly with deionized water, and dry to obtain functionalized halloysite nanotubes rich in imino, hydroxyl, and chloro groups.

[0053] (2) Preparation of functionalized halloysite nanotube membranes

[0054] 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 off the filter membrane to obtain a functionalized halloysite nanotube membrane with a diameter of 10 cm and a grammage of 15 g / m 2 of.

[0055] (3) Preparation of functionalized halloysite nanotube / polyaniline composite membranes

[0056] 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 soak the obtained functionalized halloysite nanotube membrane in the prepared aniline monomer solution at 5 °C for 15 min. Take out the functional membrane and soak it in ammonium persulfate solution (0.2 mol / L) at 5 °C for 6 min. Pour out the excess solution, and continue the reaction at 5 °C for 5 h. Dry at room temperature to obtain the composite membrane.

[0057] The obtained composite membrane is placed in N, N Soak it in a dimethylformamide solution for 1 h. Wash it thoroughly and dry it to obtain a functionalized halloysite nanotube-based composite membrane. The adsorption capacity of lead ions is determined according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0058] Example 4

[0059] 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 is taken for suction filtration to form a membrane, and a functionalized halloysite nanotube membrane with a diameter of 10 cm and a grammage of 10 g / m 2 is obtained. The remaining steps are the same as those in Example 1. The adsorption capacity of the obtained composite membrane for lead ions is determined according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0060] Example 5

[0061] The difference between this example and Example 1 is that in step (2) of this example, 157 ml of the cross-linking reaction solution is taken for suction filtration to form a membrane, and a functionalized halloysite nanotube membrane with a diameter of 10 cm and a grammage of 15 g / m 2 is obtained. The remaining steps are the same as those in Example 1. The adsorption capacity of the obtained composite membrane for lead ions is determined according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0062] Comparative Example 1

[0063] Ultrasonically disperse 1 g of halloysite nanotubes (Xianfeng Nano, CAS No.: 1332-58-7, product number: 103763) in 2000 mL of N , N dimethylformamide. After ultrasonic dispersion is uniform, take 78.5 mL of the reaction solution for suction filtration, wash it repeatedly with deionized water, and after drying, peel the sample membrane from the filter membrane to obtain a pure halloysite nanotube membrane with a diameter of 10 cm and a grammage of 5 g / m 2 . The adsorption capacity of lead ions is determined according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0064] Comparative Example 2

[0065] Prepare functionalized halloysite nanotubes according to step (1) in Example 1, and then ultrasonically disperse 1 g of functionalized halloysite nanotubes in 2000 mL of N , N dimethylformamide. After ultrasonic dispersion is uniform, take 78.5 mL of the reaction solution for suction filtration, wash it repeatedly with deionized water, and after drying, peel the sample membrane from the filter membrane to obtain a membrane with a diameter of 10 cm and a grammage of 5 g / m 2The uncrosslinked functionalized halloysite nanotube membrane, its adsorption capacity for lead ions was determined according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0066] Comparative Example 3

[0067] Prepare the crosslinked functionalized halloysite nanotube membrane according to steps (1) and (2) in Example 1, but do not perform step (3). The adsorption capacity of the functionalized halloysite nanotube membrane for lead ions was determined according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0068] Comparative Example 4

[0069] Prepare the functionalized halloysite nanotube / polyaniline composite membrane according to steps (1), (2), and (3) in Example 1, but in the third step, the composite membrane was not subjected to in-situ crosslinking treatment. The adsorption capacity of the composite membrane for lead ions was determined according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0070] Table 1 Adsorption amount of lead ions by the membranes prepared in Examples 1-5 and Comparative Examples 1-4

[0071]

[0072] It can be seen from the above results that in the composite membranes 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 each other. 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 membrane with a rich pore structure. Relying on these three advantages, the prepared composite membrane shows excellent adsorption ability for lead ions, and its adsorption amount of lead ions can reach 351 mg / g. In contrast, the halloysite nanotube membranes 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 membrane 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 membrane is ignored. Therefore, the adsorption capacity of the adsorption materials prepared in the comparative examples for lead ions cannot be compared with that of the functionalized halloysite nanotube / composite membrane prepared in the examples.

[0073] It should be noted that although theoretically increasing the mass of the membrane can provide more adsorption sites, this also means that the membrane will become thicker (while keeping the diameter unchanged). However, the increase in membrane thickness will hinder the penetration of metal ions into the interior of the membrane, resulting in a decrease in mass transfer efficiency, which in turn affects the total amount of metal ions adsorbed. Therefore, when the membrane thickness exceeds a certain critical value, the actual increase in adsorption capacity will no longer match the expectation and may even decrease, as shown by the results of Examples 1, 4, and 5.

Claims

1. A preparation method of a functionalized halloysite nanotube / polyaniline composite membrane, characterized in that, It includes the following steps: (1) Halloysite nanotubes are ultrasonically dispersed in toluene and KH550 is added. After the reaction, filtration, washing and drying are carried out to obtain KH550-modified halloysite nanotubes. Then, ring-opening reaction of epichlorohydrin with KH550-modified halloysite nanotubes is carried out to obtain functionalized halloysite nanotubes containing imino, hydroxyl and chloro groups; (2)Utilize the substitution reaction of amino group and chlorine. Using polyamine compounds as crosslinking agents, crosslinking between functionalized halloysite nanotubes is achieved. Specifically, the functionalized halloysite nanotubes are ultrasonically dispersed in acetonitrile. Under nitrogen protection, a polyamino compound and an acid-binding agent are added for crosslinking reaction. Then, it is filtered to form a film, washed, and dried to obtain a functionalized halloysite nanotube film with a grammage not greater than 15 g / m 2 . The polyamino compound is one of triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine; (3) In-situ polymerize polyaniline in the functionalized halloysite nanotube membrane and conduct in-situ crosslinking to obtain a functionalized halloysite nanotube / polyaniline composite membrane. The in-situ crosslinking is to soak the obtained composite membrane in a crosslinking agent solution at 50-70 °C for 1-2 h and then wash and dry it. The crosslinking agent solution is an N , N -dimethylformamide solution with a concentration of 8-10 mg / mL.

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

3. The preparation method of the functionalized halloysite nanotube / polyaniline composite film according to claim 1, characterized in that, Specifically, in the step (1), KH550-modified halloysite nanotubes are ultrasonically dispersed in an aqueous sodium carbonate solution, and then epichlorohydrin is added for ring-opening reaction, followed by 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%.

4. The preparation method of the functionalized halloysite nanotube / polyaniline composite film according to claim 1, characterized in that, In the step (1), the ring-opening reaction is carried out with stirring at 30-70 °C for 2-5 h.

5. The preparation method of the functionalized halloysite nanotube / polyaniline composite film according to claim 1, characterized in that, In the step (2), the mass ratio of the functionalized halloysite nanotubes, polyamino compound and acid-binding agent is 1:(0.5-2):(1-2).

6. The preparation method of the functionalized halloysite nanotube / polyaniline composite film according to claim 5, characterized in that, In the step (2), the cross-linking reaction is carried out with stirring at 60-70 °C for 8-12 h.

7. The preparation method of the functionalized halloysite nanotube / polyaniline composite film according to claim 5, characterized in that, The acid-binding agent is pyridine or triethylamine.

8. The preparation method of the functionalized halloysite nanotube / polyaniline composite film according to claim 1, characterized in that, In the step (3), the functionalized halloysite nanotube film 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, and then the excess oxidant solution is poured out. After continuing the reaction for 5-9 h, it is dried at room temperature to obtain a composite film, and then in-situ cross-linking is carried out.

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