Preparation method of multifunctional group synergistic modified aluminosilicate nanofiber membrane

Abstract

The invention discloses a preparation method of a multi-functional group synergistically modified aluminum silicate nanofiber membrane, which comprises the steps of: modifying aluminum silicate nanofibers with an amino silane coupling agent to obtain amino-functionalized aluminum silicate nanofibers; through the substitution reaction of amino and chlorine, grafting a polyamino compound onto the surface of the amino-functionalized aluminum silicate nanofibers by the cross-linking action of 1,3-dichloropropanol to obtain multi-functionalized aluminum silicate nanofibers; using an ammonia-aldehyde condensation reaction to modify 2-butenal on the surface of the multi-functionalized aluminum silicate nanofibers, thereby obtaining multi-functionalized aluminum silicate nanofibers rich in double bonds; using itaconic acid as a monomer and the multi-functionalized aluminum silicate nanofibers rich in double bonds as a cross-linking agent to carry out cross-linking polymerization, and then carrying out suction filtration to form a membrane, and drying to obtain a multi-functional group synergistically modified aluminum silicate nanofiber membrane with a grammage not exceeding 15 g / m 2 . The invention realizes the efficient adsorption of heavy metals and solves the problem that it is difficult to recycle aluminum silicate nanofibers.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminosilicate fiber membranes, and particularly to a preparation method of a multi-functional group synergistically modified aluminosilicate nanofiber membrane. Background Art

[0002] At present, for the removal of heavy metal ions in wastewater, a variety of effective technologies have been developed, including flocculation, chemical precipitation, membrane filtration technology, ion exchange method, adsorption method, etc. Among them, the adsorption method is widely used due to its advantages such as simple operation and recyclable adsorbent. However, traditional adsorption materials have deficiencies such as limited ability to remove heavy metal ions and high costs. As a new type of nano-mineral fiber material, aluminosilicate nanofibers have the advantages of being non-toxic, harmless, environmentally friendly, easy to regenerate, and having a highly developed pore structure, a large specific surface area, and excellent cation exchange performance. Therefore, they show great application potential in the field of heavy metal wastewater treatment. However, aluminosilicate nanofibers exist in powder form. Directly using them as adsorbents requires cumbersome secondary separation, and it is difficult to completely separate them, with a risk of leakage, which is likely to cause secondary pollution to the environment. In addition, the types of surface functional groups are relatively single and the quantity is limited, which to a certain extent restricts their adsorption efficiency for heavy metal ions. Summary of the Invention

[0003] Aiming at the above-mentioned defects of the existing technology, the present invention provides a preparation method of a multi-functional group synergistically modified aluminosilicate nanofiber membrane to achieve efficient adsorption of heavy metals and at the same time solve the problem of difficult recovery of aluminosilicate nanofibers.

[0004] The technical solution of the present invention is as follows: A preparation method of a multi-functional group synergistically modified aluminosilicate nanofiber membrane includes the following steps:

[0005] (1) Modify aluminosilicate nanofibers with an amino-silane coupling agent to obtain amino-functionalized aluminosilicate nanofibers;

[0006] (2) Through the substitution reaction of amino and chlorine, graft a multi-amino compound onto the surface of the amino-functionalized aluminosilicate nanofibers by the cross-linking action of 1,3-dichloropropanol to obtain multi-functionalized aluminosilicate nanofibers;

[0007] (3) Modify 2-butenal on the surface of the multi-functionalized aluminosilicate nanofibers by an ammonia-aldehyde condensation reaction to obtain multi-functionalized aluminosilicate nanofibers rich in double bonds;

[0008] (4) Using itaconic acid as a monomer and the multi-functionalized aluminosilicate nanofibers rich in double bonds as a cross-linking agent, carry out cross-linking polymerization, and then perform suction filtration to form a membrane. After drying, a membrane with a grammage not exceeding 15 g / m 2Multi-functional synergistic modified aluminum silicate nanofiber membrane.

[0009] Further, step (1) specifically involves ultrasonically dispersing aluminum silicate nanofibers in a mixed solution of ethanol and water, then adding an amino silane coupling agent and stirring for reaction. After the reaction, filtration, washing, and drying are carried out to obtain amino-functionalized aluminum silicate nanofibers, where the mass ratio of aluminum silicate nanofibers to the amino silane coupling agent is 1:(0.1 - 0.5).

[0010] Further, the stirring reaction in step (1) is a reflux reaction at 80 - 90 °C for 10 - 16 h, and the amino silane coupling agent is one of 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

[0011] Further, step (2) specifically involves ultrasonically dispersing the amino-functionalized aluminum silicate nanofibers in acetonitrile. Under nitrogen protection, 1,3-dichloropropanol and a deacidifying agent are added, and stirring reaction is carried out. Then, a multi-amino compound is added, and stirring reaction continues. After the reaction, filtration, washing, and drying are carried out to obtain multi-functionalized aluminum silicate nanofibers, where the mass ratio of amino-functionalized aluminum silicate nanofibers, 1,3-dichloropropanol, the deacidifying agent, and the multi-amino compound is 1:(0.3 - 0.7):(1.5 - 2.5):(0.5 - 2), and the deacidifying agent is one of triethylamine and pyridine.

[0012] Further, the stirring reaction in step (2) is a reflux reaction at 60 - 70 °C for 8 - 12 h.

[0013] Further, the multi-amino compound is one of triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0014] Further, step (3) specifically involves ultrasonically dispersing the multi-functionalized aluminum silicate nanofibers in absolute ethanol, adding 2-butenal, and stirring for reaction. After the reaction, filtration, washing, and drying are carried out to obtain multi-functionalized aluminum silicate nanofibers rich in double bonds, where the dosage ratio of multi-functionalized aluminum silicate nanofibers to 2-butenal is 1 g:(2 - 3) ml.

[0015] Further, the stirring reaction in step (3) is carried out at room temperature for 3 - 5 h.

[0016] Further, step (4) specifically involves ultrasonically dispersing the multi-functionalized aluminum silicate nanofibers rich in double bonds in N , NIn an N,N-dimethylformamide solution, itaconic acid and the initiator azobisisobutyronitrile were added under a protective atmosphere for cross-linking polymerization reaction, where the mass ratio of the polyfunctionalized aluminum silicate nanofibers rich in double bonds, itaconic acid, and azobisisobutyronitrile was 1:(1 - 3):(0.02 - 0.04).

[0017] Furthermore, in the step (4), the cross-linking polymerization reaction was carried out at 60 - 100 °C for 12 - 20 h.

[0018] The present invention first uses 1,3-dichloropropanol as a "bridge" to graft polyamino compounds onto the surface of amino-functionalized aluminum silicate nanofibers, thereby introducing a large number of hydroxyl, amino, and imino groups onto its surface. Furthermore, by means of an ammonia-aldehyde condensation reaction, 2-butenal was grafted onto the surface of the polyfunctionalized fibers, thereby introducing double bonds onto its surface. Finally, starting from the interface structure design, using the prepared polyfunctionalized aluminum silicate nanofibers rich in double bonds as a cross-linking agent and itaconic acid containing double bonds and multiple carboxyl groups as a monomer, a cross-linking copolymerization reaction was carried out, which not only achieved the cross-linking modification of aluminum silicate nanofibers but also further introduced a large number of carboxyl groups with adsorption activity. Thus, by means of a simple vacuum filtration technique, an aluminum silicate nanofiber composite membrane with excellent structural stability and adsorption performance was prepared.

[0019] The advantages of the present invention compared with the prior art are as follows:

[0020] The present invention first greatly enriches the types and amounts of surface functional groups of aluminum silicate nanofibers through a multi-step modification method, further introduces double bonds onto the surface of the polyfunctionalized aluminum silicate nanofibers, and introduces polymerization monomers for cross-linking polymerization modification between fibers, which not only forms good interfacial bonding but also introduces more heavy metal ion binding sites. A polyfunctional synergistic modified aluminum silicate nanofiber membrane with excellent structural stability and adsorption performance was prepared by a simple filtration technique, achieving its efficient adsorption of heavy metals, and at the same time solving the problem that nano-powder materials are not easily recycled, effectively promoting the application of magnesium silicate nanofibers in the adsorption field. Specific embodiments

[0021] The following examples are used to further illustrate the present invention, but do not limit the present invention.

[0022] Example 1

[0023] A preparation method of a polyfunctional synergistic modified aluminum silicate nanofiber membrane, comprising the following steps:

[0024] (1) 1 g of aluminosilicate nanofibers was ultrasonically dispersed in absolute ethanol, and 0.1 g of 3-aminopropyltrimethoxysilane was added. The mixture was refluxed and stirred at 80 °C for 16 h. After the reaction, suction filtration was carried out, and the product was alternately washed with ethanol and deionized water and then dried to obtain amino-functionalized aluminosilicate nanofibers. The aluminosilicate nanofibers were sourced from Shanghai Macklin Biochemical Co., Ltd., CAS: 1327-36-2. The sources of aluminosilicate nanofibers used hereinafter were the same.

[0025] (2) 1 g of amino-functionalized aluminosilicate nanofibers was ultrasonically dispersed in acetonitrile. Under nitrogen protection, 0.3 g of 1,3-dichloropropanol and 1.5 g of triethylamine were added. The mixture was stirred at 60 °C for 12 h, then 0.5 g of triethylenetetramine was added, and the mixture was continuously stirred at 60 °C for 12 h. After the reaction, suction filtration was carried out, and the product was alternately washed with ethanol and deionized water and then dried to obtain multi-functionalized aluminosilicate nanofibers.

[0026] (3) 1 g of multi-functionalized aluminosilicate nanofibers was ultrasonically dispersed in absolute ethanol, and 2 mL of 2-butenal was added. The mixture was stirred at room temperature for 3 h. After the reaction, suction filtration was carried out, and the product was alternately washed with ethanol and deionized water and then dried to obtain multi-functionalized aluminosilicate nanofibers rich in double bonds.

[0027] (4) 1 g of multi-functionalized aluminosilicate nanofibers rich in double bonds was ultrasonically dispersed in N , N -dimethylformamide solution. Under N 2 protection, 1 g of itaconic acid and 0.02 g of azobisisobutyronitrile were added. The mixture was stirred at 60 °C for 20 h. After cooling to room temperature, solvent was added to make the reaction system reach 2000 mL. 38.9 mL of the reaction solution was taken for suction filtration, and the sample film was peeled off from the filter membrane after being repeatedly washed with deionized water and dried, to obtain a multi-functional synergistic modified sodium silicate nanofiber membrane with a diameter of 10 cm and a grammage of 5 g / m 2 .

[0028] The adsorption performance test experiment of the multi-functional synergistic modified aluminosilicate nanofiber membrane prepared in Example 1 is as follows:

[0029] 100 mL of an aqueous solution with a lead ion (lead nitrate as the reagent) concentration of 100 mg / L was prepared in a flask. After adjusting the pH of the solution to 7 with 0.1 M NaOH, the prepared multi-functional synergistic modified aluminosilicate nanofiber membrane was added. Then, in a constant temperature shaker at 30 °C, adsorption was carried out at a rotation speed of 200 rpm for 3 h. After adsorption, the supernatant was taken, and the concentration of lead ions in the supernatant was measured by ICP-OES. The adsorption capacity of the adsorbent for lead ions ( Q , mg / g) was calculated by the following formula, and the results are listed in Table 1.

[0030] Q = ( C 0 - C t ) V / M

[0031] Q where 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 (mg).

[0032] Example 2

[0033] A preparation method of a multi-functional group synergistic modified aluminosilicate nanofiber membrane, comprising the following steps:

[0034] (1) Ultrasonically disperse 1 g of aluminosilicate nanofibers in anhydrous ethanol, add 0.3 g of 3-aminopropyltrimethoxysilane, reflux and stir at 85 °C for 13 h, and after the reaction, perform suction filtration, alternately wash with ethanol and deionized water, and dry to obtain amino-functionalized aluminosilicate nanofibers.

[0035] (2) Ultrasonically disperse 1 g of amino-functionalized aluminosilicate nanofibers in acetonitrile, under nitrogen protection, add 0.5 g of 1,3-dichloropropanol and 2 g of triethylamine, stir and react at 65 °C for 10 h, then add 1.25 g of triethylenetetramine, and continue to stir and react at 65 °C for 10 h. After the reaction, perform suction filtration, alternately wash with ethanol and deionized water, and dry to obtain multi-functionalized aluminosilicate nanofibers.

[0036] (3) Ultrasonically disperse 1 g of multi-functionalized aluminosilicate nanofibers in anhydrous ethanol, add 2.5 ml of 2-butenal, stir and react at room temperature for 4 h. After the reaction, perform suction filtration, alternately wash with ethanol and deionized water, and dry to obtain multi-functionalized aluminosilicate nanofibers rich in double bonds.

[0037] (4) Ultrasonically disperse 1 g of multi-functionalized aluminosilicate nanofibers rich in double bonds in N , N -dimethylformamide solution, under N 2 protection, add 2 g of itaconic acid and 0.03 g of azobisisobutyronitrile, stir and react at 80 °C for 16 h. After cooling to room temperature, add solvent to make the reaction system reach 2000 mL. Take 51.8 mL of the reaction solution for suction filtration, wash repeatedly with deionized water, and dry. Then peel the sample membrane from the filter membrane to obtain a membrane with a diameter of 10 cm and a grammage of 10 g / m 2The multi-functional group synergistically modified sodium silicate nanofiber membrane.

[0038] Example 3

[0039] A preparation method of a multi-functional group synergistically modified aluminum silicate nanofiber membrane, comprising the following steps:

[0040] (1) Ultrasonically disperse 1 g of aluminum silicate nanofibers in anhydrous ethanol, add 0.5 g of 3-aminopropyltrimethoxysilane, reflux and stir at 90 °C for 10 h, and after the reaction, perform suction filtration, and wash alternately with ethanol and deionized water, and dry to obtain amino-functionalized aluminum silicate nanofibers.

[0041] (2) Ultrasonically disperse 1 g of amino-functionalized aluminum silicate nanofibers in acetonitrile, under nitrogen protection, add 0.7 g of 1,3-dichloropropanol and 2.5 g of triethylamine, stir and react at 70 °C for 8 h, then add 2 g of triethylenetetramine, and continue to stir and react at 70 °C for 8 h. After the reaction, perform suction filtration, and wash alternately with ethanol and deionized water, and dry to obtain multi-functionalized aluminum silicate nanofibers.

[0042] (3) Ultrasonically disperse 1 g of multi-functionalized aluminum silicate nanofibers in anhydrous ethanol, add 3 ml of 2-butenal, stir and react at room temperature for 5 h, and after the reaction, perform suction filtration, and wash alternately with ethanol and deionized water, and dry to obtain multi-functionalized aluminum silicate nanofibers rich in double bonds.

[0043] (4) Ultrasonically disperse 1 g of multi-functionalized aluminum silicate nanofibers rich in double bonds in N , N -dimethylformamide solution, under N 2 protection, add 3 g of itaconic acid and 0.04 g of azobisisobutyronitrile, stir and react at 100 °C for 20 h, cool to room temperature, add solvent to make the reaction system reach 2000 mL, take 58.3 mL of the reaction solution for suction filtration, wash repeatedly with deionized water, and dry, then peel the sample membrane from the filter membrane to obtain a multi-functional group synergistically modified sodium silicate nanofiber membrane with a diameter of 10 cm and a grammage of 15 g / m 2 The multi-functional group synergistically modified sodium silicate nanofiber membrane.

[0044] Example 4

[0045] A preparation method of a multi-functional group synergistically modified aluminum silicate nanofiber membrane, steps (1), (2), and (3) are the same as those in Example 1, and step (4) is to ultrasonically disperse 1 g of multi-functionalized aluminum silicate nanofibers rich in double bonds in N , N -dimethylformamide solution, under N 2Under protection, 1 g of itaconic acid and 0.02 g of azobisisobutyronitrile were added, and the mixture was stirred and reacted at 60 °C for 20 h. After cooling to room temperature, solvent was added to make the reaction system reach 2000 mL. 77.8 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 multi-functional group synergistically modified sodium silicate nanofiber membrane with a diameter of 10 cm and a grammage of 10 g / m 2

[0046] Example 5

[0047] A preparation method of a multi-functional group synergistically modified aluminum silicate nanofiber membrane. Steps (1), (2), and (3) are the same as those in Example 1. Step (4) is to ultrasonically disperse 1 g of polyfunctionalized aluminum silicate nanofibers rich in double bonds in N , N -dimethylformamide solution. Under N 2 protection, 1 g of itaconic acid and 0.02 g of azobisisobutyronitrile were added, and the mixture was stirred and reacted at 60 °C for 20 h. After cooling to room temperature, solvent was added to make the reaction system reach 2000 mL. 116.7 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 multi-functional group synergistically modified sodium silicate nanofiber membrane with a diameter of 10 cm and a grammage of 15 g / m 2

[0048] Comparative Example 1

[0049] 1 g of raw aluminum silicate nanofibers was ultrasonically dispersed in 2000 mL of 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 sodium silicate nanofiber membrane with a diameter of 10 cm and a grammage of 5 g / m 2 . Its adsorption performance was measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0050] Comparative Example 2

[0051] Aminated magnesium silicate nanofibers were prepared according to step (1) in Example 1. Then, 1 g of aminated aluminum silicate nanofibers was ultrasonically dispersed in 2000 mL of 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 aminated sodium silicate nanofiber membrane with a diameter of 10 cm and a grammage of 5 g / m 2 . Its adsorption performance was measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1. ​​

[0052] Comparative Example 3

[0053] Prepare the multi-functionalized aluminum silicate nanofibers according to steps (1) and (2) in Example 1, and then ultrasonically disperse 1 g of the multi-functionalized aluminum silicate nanofibers in 2000 mL of N , N N,N-dimethylformamide, ultrasonically disperse evenly, take 78.5 mL of the reaction solution for suction filtration, wash repeatedly with deionized water, and after drying, peel the sample film off the filter membrane to obtain a multi-functionalized sodium silicate nanofiber membrane with a diameter of 10 cm and a grammage of 5 g / m 2 . The adsorption performance was measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0054] Comparative Example 4

[0055] Prepare the multi-functionalized aluminum silicate nanofibers rich in double bonds according to steps (1), (2), and (3) in Example 1, and then ultrasonically disperse 1 g of the multi-functionalized aluminum silicate nanofibers rich in double bonds in 2000 mL of N , N N,N-dimethylformamide, ultrasonically disperse evenly, take 78.5 ml of the reaction solution for suction filtration, wash repeatedly with deionized water, and after drying, peel the sample film off the filter membrane to obtain a multi-functionalized sodium silicate nanofiber membrane rich in double bonds with a diameter of 10 cm and a grammage of 5 g / m 2 . The adsorption performance was measured according to the adsorption performance experiment of the product in Example 1, and the results are listed in Table 1.

[0056] Table 1 Adsorption capacity of aluminum silicate nanofiber membranes prepared in Examples 1-5 and Comparative Examples 1-3 for lead ions

[0057]

[0058] It can be seen from the above results that the multi-functional group synergistically modified aluminum silicate nanofiber membrane prepared by the present invention exhibits excellent adsorption ability for lead ions by virtue of its rich functional groups and strong covalent bond cross-linking structure between nanofibers. In particular, the more the number and types of functional groups on the surface of the aluminum silicate nanofibers, the stronger the adsorption capacity of the membrane for lead ions, which is verified by the experimental data of Examples 1 to 5 and Comparative Examples 1 to 4.

[0059] Comparing the results of Example 1 and Comparative Example 4, it can be clearly seen that the cross-linking structure between aluminum silicate nanofibers plays an important role in improving the adsorption performance of the fiber membrane. Through cross-linking polymerization modification, a strong interfacial bond is formed between aluminum silicate nanofibers under the dual action of hydrogen bonds and covalent bonds, effectively improving the permeation flux of the membrane. Moreover, a large number of carboxyl functional groups are introduced during the cross-linking polymerization reaction, providing more abundant binding sites for heavy metal ions.

[0060] In addition, it is worth noting that although increasing the mass of the membrane can theoretically provide more adsorption sites, when the diameter remains unchanged, increasing the mass means increasing the thickness of the membrane. The increase in membrane thickness will hinder metal ions from entering the membrane, resulting in a decrease in mass transfer efficiency, which in turn affects the adsorption amount of metal ions. Therefore, when the membrane thickness exceeds a certain threshold, the growth of its actual adsorption amount will no longer meet expectations and may even show a downward trend, as shown in the results of Example 1, Example 4, and Example 5.

Claims

1. A method for preparing a multi-functional group synergistically modified aluminum silicate nanofiber membrane, characterized in that: The following steps are involved: (1) Aluminum silicate nanofibers are modified by using an aminosilane coupling agent to obtain amino-modified aluminum silicate nanofibers; (2) grafting a polyamino compound onto the surface of the amino-modified aluminum silicate nanofibers by a substitution reaction of amino groups and chlorine using a cross-linking effect of 1,3-dichloropropanol to obtain multifunctional aluminum silicate nanofibers, wherein the polyamino compound is one of triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine; (3) modifying the surface of the multifunctional aluminum silicate nanofibers with 2-butenal by an ammonia-aldehyde condensation reaction, thereby obtaining multifunctional aluminum silicate nanofibers rich in double bonds; (4) using itaconic acid as a monomer and the double-bond-rich multifunctional aluminum silicate nanofibers as a crosslinking agent, performing crosslinking polymerization, and then performing suction filtration to form a membrane, and obtaining a film having a gram weight of no more than 15 g / m 2 Multi-functional groups synergistically modified aluminum silicate nanofiber membrane.

2. The method for preparing the multi-functional group synergistically modified aluminum silicate nanofiber membrane according to claim 1, characterized in that: The step (1) specifically comprises ultrasonically dispersing the aluminum silicate nanofibers in a mixture of ethanol and water, then adding an aminosilane coupling agent for stirring and reacting, and after the reaction, filtering, washing and drying to obtain amino-treated aluminum silicate nanofibers, wherein the mass ratio of the aluminum silicate nanofibers to the aminosilane coupling agent is 1:(0.1-0.5).

3. The method for preparing the multi-functional group synergistically modified aluminum silicate nanofiber membrane according to claim 2, characterized in that: The stirring reaction in step (1) is refluxed at 80-90° C. for 10-16 hours, and the aminosilane coupling agent is one of 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

4. The method for preparing the multi-functional group synergistically modified aluminum silicate nanofiber membrane according to claim 1, characterized in that: The step (2) specifically comprises ultrasonically dispersing the amino aluminum silicate nanofibers in acetonitrile, adding 1,3-dichloropropanol and an acid binding agent under nitrogen protection, stirring and reacting, then adding the polyamino compound, continuing to stir and react, filtering and washing after the reaction, and drying to obtain the multifunctional aluminum silicate nanofibers, wherein the mass ratio of the amino aluminum silicate nanofibers, 1,3-dichloropropanol, the acid binding agent and the polyamino compound is 1: (0.3-0.7): (1.5-2.5): (0.5-2), and the acid binding agent is one of triethylamine and pyridine.

5. The method for preparing the multi-functional group synergistically modified aluminum silicate nanofiber membrane according to claim 4, characterized in that: The stirring reaction in step (2) is carried out under reflux at 60-70° C. for 8-12 hours.

6. The method for preparing the multi-functional group synergistically modified aluminum silicate nanofiber membrane according to claim 1, characterized in that: The step (3) specifically comprises ultrasonically dispersing the multifunctional aluminum silicate nanofibers in anhydrous ethanol, adding 2-butenal, stirring to react, and filtering, washing, and drying after the reaction to obtain multifunctional aluminum silicate nanofibers rich in double bonds, wherein the dosage ratio of the multifunctional aluminum silicate nanofibers to 2-butenal is 1 g: (2 to 3) ml.

7. The method for preparing the multi-functional group synergistically modified aluminum silicate nanofiber membrane according to claim 6, characterized in that: The stirring reaction in step (3) is carried out at room temperature for 3 to 5 hours.

8. The method for preparing the multi-functional group synergistically modified aluminum silicate nanofiber membrane according to claim 1, characterized in that: The step (4) specifically comprises ultrasonically dispersing the double-bond-rich multifunctional aluminum silicate nanofibers in N , N -dimethylformamide solution, adding itaconic acid and initiator azobisisobutyronitrile under protective atmosphere to carry out cross-linking polymerization reaction, wherein the mass ratio of double-bond-rich multifunctional aluminum silicate nanofibers, itaconic acid and azobisisobutyronitrile is 1: (1-3): (0.02-0.04).

9. The method for preparing the multi-functional group synergistically modified aluminum silicate nanofiber membrane according to claim 8, characterized in that: The cross-linking polymerization reaction in step (4) is carried out at 60-100° C. for 12-20 hours.

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