SiO2 (at) LDHs nano composite material with high adsorption efficiency and preparation method of SiO2 (at) LDHs nano composite material

Abstract

The invention relates to the technical field of composite materials, and particularly discloses a SiO2-coated LDHs nano composite material with high adsorption efficiency and a preparation method thereof.The preparation method comprises the steps that SiO2 nano particles are modified through double coupling agents, chitosan and F127 double template agents are combined to synthesize an LDHs precursor, and then the LDHs precursor is prepared into the SiO2-coated LDHs nano composite material. In-situ growth of a core-shell structure is realized by using a micro-channel reactor, an interface is strengthened by depositing Al2O3 through ALD, and interlayer ions are finally pre-loaded through hierarchical pore carbonization and thermo-sensitive-light response polymer grafting, so that the SiO2 (at) LDHs composite material with triple interface protection, a hierarchical pore structure and an intelligent response function is formed, the adsorption capacity and the cycling stability are remarkably improved, and the application range is wide. And the production cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and more particularly, to a SiO2@LDHs nanocomposite with high adsorption efficiency and a preparation method thereof. Background Art

[0002] The SiO2@LDHs nanocomposite is a core-shell structure or composite system formed by combining silicon dioxide with layered double hydroxides (LDHs), which can be used as an adsorbent for environmental treatment. The ion exchange ability of LDHs can adsorb anions such as Cr 6+ and AsO4 3- in wastewater, while the high specific surface area of SiO2 can enhance the adsorption capacity.

[0003] Existing SiO2@LDHs nanocomposites are mainly prepared by hydrothermal method or co-precipitation method. However, SiO2@LDHs prepared by traditional co-precipitation method or hydrothermal method often have many problems. Firstly, the SiO2 core and the LDHs shell are mainly connected by physical adsorption or weak chemical bonds (such as hydrogen bonds), and the shell is prone to shedding in the adsorption-desorption cycle or high-salt / acid-base environment. This structural instability results in poor reusability of the material. Secondly, the adsorption sites of SiO2@LDHs nanocomposites prepared by conventional methods are limited, resulting in poor adsorption performance. Finally, the regeneration and recycling of SiO2@LDHs nanocomposites prepared by conventional methods are relatively difficult. Although the adsorption capacity of LDHs can be restored by acid, base elution or pyrolysis after adsorption saturation, it still causes irreversible damage to the material structure.

[0004] Therefore, it is necessary to design a preparation method of SiO2@LDHs nanocomposites to solve the problems of low interfacial binding force, poor adsorption performance and difficult recycling of the current preparation methods of SiO2@LDHs nanocomposites. Summary of the Invention

[0005] In view of this, the present invention provides a preparation method of a SiO2@LDHs nanocomposite with high adsorption efficiency, aiming to solve the problems of low interfacial binding force, poor adsorption performance and difficult recycling of the current preparation methods of SiO2@LDHs nanocomposites.

[0006] On the one hand, the present invention provides a preparation method of a SiO2@LDHs nanocomposite with high adsorption efficiency, and the steps of the preparation method include:

[0007] TEOS was mixed with ethanol and then subjected to the first dispersion. Ammonia water was added until the pH value of the solution reached 9, and then 3-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane were added successively, followed by the first mixing to obtain SiO2NH2 / SH;

[0008] Mg(NO3)2·6H2O, Al(NO3)3·9H2O, chitosan and F127 were dissolved in water and subjected to the second dispersion. Subsequently, NaOH solution was added until the pH of the solution reached 10, and then the first treatment was carried out to obtain a precursor suspension;

[0009] The SiO2NH2 / SH was put into the precursor suspension for the third dispersion. After adding NaOH solution to adjust the pH to 10, the second treatment was carried out to obtain SiO2@LDHs;

[0010] The SiO2@LDHs was subjected to carbonization treatment, and then dispersed in a mixed solution of Azo monomer and NIPAM. A photoinitiator was added to obtain a mixed solution. The mixed solution was subjected to ultraviolet irradiation treatment and post-treatment to obtain SiO2@C@LDHs-PNIPAM-co-Azo;

[0011] The SiO2@C@LDHs-PNIPAM-co-Azo was immersed in p-aminobenzenesulfonic acid solution, and after oscillation, centrifugation, washing and drying in sequence, the SiO2@LDHs nanocomposite with high adsorption efficiency was obtained.

[0012] Furthermore, the first dispersion, the second dispersion and the third dispersion were all ultrasonic dispersions, and the dispersion times were 15 minutes, 15 minutes and 30 minutes in sequence.

[0013] Furthermore, the first treatment was as follows: the solution was transferred to a microchannel reactor and treated at 180 °C with a flow rate of 10 mL / min for 5 minutes, and then centrifuged and washed after cooling.

[0014] Furthermore, the second treatment was specifically as follows: the solution was treated at 180 °C in a microwave continuous flow reactor for 5 minutes, and after centrifugation and drying, 10 cycles of Al2O3 layers were deposited on the surface by atomic layer deposition.

[0015] Furthermore, the carbonization treatment was as follows: the SiO2@LDHs was carbonized at 350 °C for 2 hours under an Ar atmosphere, and then heated to 500 °C and carbonized for 1 hour.

[0016] Furthermore, the ultraviolet irradiation treatment was as follows: the mixed solution was irradiated with ultraviolet light of 365 nm for 30 minutes;

[0017] The post-treatment was specifically as follows: the irradiated mixed solution was centrifuged, washed and freeze-dried in sequence.

[0018] Further, the oscillation time is 24 hours.

[0019] Further, after the first mixing is completed, the obtained SiO2NH2 / SH is centrifuged, washed, and dried in sequence.

[0020] Further, the mass ratio of the Azo monomer to NIPAM in the Azo monomer and NIPAM mixed solution is 5:45.

[0021] On the other hand, the present invention also provides a SiO2@LDHs nanocomposite with high adsorption efficiency prepared by the preparation method of the SiO2@LDHs nanocomposite with high adsorption efficiency.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: First, the present invention uses 3-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane (MPTMS) to perform double modification on the surface of SiO2 in sequence to form -Si-NH2 and -Si-SH bifunctional groups, and enhances the interfacial covalent bonding with LDHs through the -Si-NH2 and -Si-SH bifunctional groups, which greatly enhances the interfacial binding force; Second, the use of chitosan and F127 as a co-template improves the specific surface area and mesoporous ratio of the SiO2@LDHs nanocomposite, and thus greatly improves its adsorption performance; Third, by grafting with PNIPAM-co-Azo copolymer, thermosensitive-photoresponsive dual-mode desorption is realized, the desorption rate is increased, the response time is shortened while the regeneration energy consumption is reduced, and the cycle life is extended; Finally, by pre-inserting p-aminobenzenesulfonate, the adsorption capacity is further increased and the desorption energy consumption is reduced. Description of the Drawings

[0023] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0024] Figure 1 It is a flowchart of the preparation method of the SiO2@LDHs nanocomposite with high adsorption efficiency provided by the embodiment of the present invention. Detailed Embodiments

[0025] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0026] Existing SiO2@LDHs nanocomposites are mainly prepared by hydrothermal method or co-precipitation method. However, SiO2@LDHs prepared by traditional co-precipitation method or hydrothermal method often have many problems. First, the SiO2 core and the LDHs shell are mainly connected by physical adsorption or weak chemical bonds (such as hydrogen bonds), and the shell is prone to shedding in the adsorption-desorption cycle or high-salt / acid-base environment. This structural instability leads to poor reusability of the material. Second, the adsorption sites of the SiO2@LDHs nanocomposites prepared by conventional methods are limited, resulting in poor adsorption performance. Finally, the regeneration and recycling of the SiO2@LDHs nanocomposites prepared by conventional methods are relatively difficult. Although the adsorption capacity of LDHs can be restored by acid, base elution or pyrolysis after adsorption saturation, it still causes irreversible damage to the material structure. Therefore, it is necessary to design a preparation method of SiO2@LDHs nanocomposites to solve the problems of low interfacial bonding force, poor adsorption performance and difficult recycling of the current SiO2@LDHs nanocomposites preparation method.

[0027] On the one hand, in some embodiments of the present invention, a preparation method of a SiO2@LDHs nanocomposite with high adsorption efficiency, the steps of the preparation method include:

[0028] Mix tetraethyl orthosilicate with ethanol and perform the first dispersion, add ammonia water until the pH value of the solution is 9, and then sequentially add 3-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane, and perform the first mixing to obtain SiO2NH2 / SH;

[0029] Dissolve Mg(NO3)2·6H2O, Al(NO3)3·9H2O, chitosan and F127 in water, perform the second dispersion, and then add NaOH solution until the pH of the solution = 10, and then perform the first treatment to obtain a precursor suspension;

[0030] Put the SiO2NH2 / SH into the precursor suspension for the third dispersion, add NaOH solution to adjust the pH to 10, and then perform the second treatment to obtain SiO2@LDHs;

[0031] The SiO2@LDHs is carbonized and then dispersed in a mixed solution of Azo monomer and NIPAM. A photoinitiator is added to obtain a mixed solution. The mixed solution is subjected to ultraviolet irradiation treatment and post-treatment to obtain SiO2@C@LDHs-PNIPAM-co-Azo;

[0032] The SiO2@C@LDHs-PNIPAM-co-Azo is soaked in a p-aminobenzenesulfonic acid solution, and after shaking, centrifuging, washing, and drying in sequence, the SiO2@LDHs nanocomposite with high adsorption efficiency is obtained.

[0033] Specifically, the concentration of the ammonia water is preferably 25%, the concentration of the NaOH is preferably 2M, the water is preferably deionized water, and the concentration of the p-aminobenzenesulfonic acid solution is preferably 0.1M; the photoinitiator is preferably Irgacure 2959.

[0034] Specifically, the raw materials used in the preparation method of the SiO2@LDHs nanocomposite with adsorption efficiency are preferably in the following parts by mass:

[0035] 900 - 1000 parts of tetraethyl orthosilicate, 7000 - 8000 parts of ethanol, 10 - 20 parts of 3-aminopropyltrimethoxysilane, 1 - 10 parts of 3-mercaptopropyltrimethoxysilane, 1000 - 1500 parts of Mg(NO3)2·6H2O, 500 - 1000 parts of Al(NO3)3·9H2O; 300 - 1000 parts of chitosan, 100 - 200 parts of F127, 10 - 100 parts of a mixed solution of Azo monomer and NIPAM, 1 - 10 parts of an initiator, 1500 - 2000 parts of a p-aminobenzenesulfonic acid solution.

[0036] More preferably: 934 parts of tetraethyl orthosilicate, 7890 parts of ethanol, 14.1 parts of 3-aminopropyltrimethoxysilane, 5.25 parts of 3-mercaptopropyltrimethoxysilane, 1200 parts of Mg(NO3)2·6H2O, 800 parts of Al(NO3)3·9H2O; 500 parts of chitosan, 150 parts of F127, 50 parts of a mixed solution of Azo monomer and NIPAM, 5 parts of an initiator, 1730 parts of a p-aminobenzenesulfonic acid solution.

[0037] Specifically, when using ammonia water to adjust the pH value, the ammonia water should be slowly added dropwise and continuously stirred for 2 hours; the first mixing is specifically: stirring at room temperature for 2 hours;

[0038] It is understandable that the SiO2 surface is doubly modified with 3-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane (MPTMS) in sequence to form -Si-NH2 and -Si-SH bifunctional groups, and the interfacial covalent bonding with LDHs is enhanced through the -Si-NH2 and -Si-SH bifunctional groups, greatly enhancing the interfacial binding force; secondly, the use of chitosan and F127 as co-templates improves the specific surface area and mesoporous ratio of the SiO2@LDHs nanocomposite, thereby greatly improving its adsorption performance; thirdly, grafting with PNIPAM-co-Azo copolymer realizes thermosensitive-photoresponsive dual-mode desorption, improves the desorption rate, shortens the response time while reducing the regeneration energy consumption, and prolongs the cycle life; finally, pre-inserting sulfanilate further improves the adsorption capacity and reduces the desorption energy consumption.

[0039] In some embodiments of the present invention, the first dispersion, the second dispersion and the third dispersion are all ultrasonic dispersions, and the dispersion times are 15 minutes, 15 minutes and 30 minutes in sequence.

[0040] It is understandable that ultrasonic dispersion can break the tetraethyl orthosilicate droplets through high-frequency vibration to form a nanoscale dispersion system, significantly increasing the specific surface area of the hydrolysis reaction, accelerating the generation of SiO2 nanoparticles, making the final SiO2 nanoparticle size more uniform (average particle size ≤ 50 nm), reducing agglomeration, and providing a more ideal surface for subsequent dual-coupling agent modification.

[0041] In some embodiments of the present application, the first treatment is: transferring the solution to a microchannel reactor and treating it at 180 °C with a flow rate of 10 mL / min for 5 minutes, followed by centrifugal washing after cooling.

[0042] It is understandable that using a microchannel reactor can achieve industrial continuous production, improve the raw material utilization rate, and reduce the energy consumption.

[0043] In some embodiments of the present application, the second treatment is specifically: treating the solution in a microwave continuous flow reactor at 180 °C for 5 minutes, followed by centrifugal drying and depositing 10 cycles of Al2O3 layer on the surface by atomic layer deposition.

[0044] Specifically, deionized water is used for washing until neutral during washing.

[0045] It is understandable that the Al2O3 layer acts as a physical barrier to prevent the LDHs shell from directly contacting the acidic environment, enhancing the pH stability.

[0046] In some embodiments of the present application, the carbonization treatment is: carbonizing the SiO2@LDHs at 350 °C for 2 hours in an Ar atmosphere, and then raising the temperature to 500 °C for carbonization for 1 hour.

[0047] It is understandable that by stepwise regulating the carbonization temperature, a hierarchical pore structure can be formed in SiO2@LDHs, further increasing the specific surface area.

[0048] In some embodiments of the present application, the ultraviolet irradiation treatment is: irradiating the mixed solution with ultraviolet light of 365 nm for 30 minutes;

[0049] The post-treatment is specifically: sequentially centrifuging, washing, and freeze-drying the mixed solution after the irradiation is completed.

[0050] Specifically, under the irradiation of 365 nm ultraviolet light, the photoinitiator decomposes to generate free radicals, initiating the free radical polymerization reaction of PNIPAM and Azo monomers, and in-situ grafting to form a temperature-sensitive and light-responsive copolymer network on the material surface. The 365 nm wavelength matches the absorption peak of the photoinitiator, and 30 minutes of irradiation ensures complete polymerization: the PNIPAM segment endows the material with temperature sensitivity, and the Azo group provides light responsiveness, and the two work together to achieve the temperature / light dual-responsive function. At the same time, the cross-linked structure formed by photopolymerization enhances the mechanical strength of the material, the thickness of the grafting layer is controllable, and the reaction conditions are mild, avoiding the damage to the material structure caused by high temperature.

[0051] In some embodiments of the present application, the oscillation time is 24 hours.

[0052] It is understandable that the material is immersed in a 0.1 M p-aminobenzenesulfonic acid (PABS) solution and oscillated for 24 hours. By mechanical oscillation, the solution and the material are promoted to fully contact, so that PABS molecules diffuse into the hierarchical pores inside the material under the drive of the concentration gradient, realizing uniform modification in three-dimensional space. The amino group (-NH2) of PABS forms a covalent bond with the active sites on the material surface (such as hydroxyl groups), and the sulfonic acid group (-SO3H) introduces negative charges, enhancing the electrostatic adsorption ability for cationic pollutants such as heavy metal ions. 24 hours of oscillation ensures that the adsorption of PABS reaches thermodynamic equilibrium, avoiding the shedding of the modification layer. At the same time, the sulfonic acid group promotes the diffusion of pollutants through the electrostatic repulsion effect in subsequent adsorption, increasing the adsorption capacity. This step also provides adjustable pH-responsive sites for the material, and cooperates with the temperature-sensitive and light-responsive polymer to achieve efficient desorption and reduce the regeneration energy consumption.

[0053] In some embodiments of the present application, after the first mixing is completed, the obtained SiO2NH2 / SH is sequentially centrifuged, washed, and dried.

[0054] Specifically, the drying is vacuum drying at 60 °C.

[0055] In some embodiments of the present application, the mass ratio of the Azo monomer to NIPAM in the Azo monomer and NIPAM mixed solution is 5:45.

[0056] On the other hand, in some embodiments of the present application, a SiO2@LDHs nanocomposite with adsorption efficiency is provided, which is prepared by the preparation method of the SiO2@LDHs nanocomposite with adsorption efficiency.

[0057] Example 1

[0058] S1. Mix 900 parts of tetraethyl orthosilicate with 7000 parts of ethanol, ultrasonically disperse for 15 minutes, slowly add ammonia water until the pH value of the solution is 9, continuously stir for 2 hours, then sequentially add 10 parts of 3-aminopropyltrimethoxysilane and 1 part of 3-mercaptopropyltrimethoxysilane, stir at room temperature for 2 hours, then centrifuge, wash, and vacuum dry at 60 °C to obtain SiO2NH2 / SH;

[0059] S2. Dissolve 1000 parts of Mg(NO3)2·6H2O, 500 parts of Al(NO3)3·9H2O, 300 parts of chitosan, and 100 parts of F127 in deionized water, ultrasonically disperse for 15 minutes, then add NaOH solution until the pH of the solution = 10, transfer the solution to a microchannel reactor, and process at 180 °C and a flow rate of 10 mL / min for 5 minutes. After cooling, centrifuge and wash to obtain a precursor suspension;

[0060] S3. Put the SiO2NH2 / SH into the precursor suspension, ultrasonically disperse for 30 minutes, add NaOH solution to adjust the pH to 10, then process the solution in a microwave continuous flow reactor at 180 °C for 5 minutes, centrifuge and dry, and deposit 10 cycles of Al2O3 layer on the surface by atomic layer deposition to obtain SiO2@LDHs;

[0061] S4. Carbonize the SiO2@LDHs at 350 °C in an Ar atmosphere for 2 hours, then raise the temperature to 500 °C and carbonize for 1 hour. Subsequently, disperse it in a mixed solution of 10 parts of Azo monomer and NIPAM, add 1 part of Irgacure2959 to obtain a mixed solution. After irradiating the mixed solution with ultraviolet light at 365 nm for 30 minutes, centrifuge, wash, and freeze-dry to obtain SiO2@C@LDHs-PNIPAM-co-Azo;

[0062] S5. Immerse the SiO2@C@LDHs-PNIPAM-co-Azo in 1500 parts of sulfanilic acid solution, oscillate for 24 hours, then centrifuge, wash, and dry to obtain the SiO2@LDHs nanocomposite with high adsorption efficiency.

[0063] Example 2

[0064] S1. Mix 1000 parts of tetraethyl orthosilicate with 8000 parts of ethanol, ultrasonically disperse for 15 minutes, slowly add ammonia water until the pH value of the solution is 9, continuously stir for 2 hours, then successively add 20 parts of 3-aminopropyltrimethoxysilane and 10 parts of 3-mercaptopropyltrimethoxysilane. After stirring at room temperature for 2 hours, centrifuge, wash, and vacuum dry at 60 °C to obtain SiO2NH2 / SH;

[0065] S2. Dissolve 1500 parts of Mg(NO3)2·6H2O, 1000 parts of Al(NO3)3·9H2O, 1000 parts of chitosan, and 200 parts of F127 in deionized water, ultrasonically disperse for 15 minutes, then add NaOH solution until the pH of the solution = 10. Transfer the solution to a microchannel reactor and treat it at 180 °C with a flow rate of 10 mL / min for 5 minutes. After cooling, centrifuge and wash to obtain a precursor suspension;

[0066] S3. Put the SiO2NH2 / SH into the precursor suspension and ultrasonically disperse for 30 minutes. After adding NaOH solution to adjust the pH to 10, treat the solution in a microwave continuous flow reactor at 180 °C for 5 minutes. After centrifugal drying, deposit 10 cycles of Al2O3 layer on the surface by atomic layer deposition to obtain SiO2@LDHs;

[0067] S4. Carbonize the SiO2@LDHs at 350 °C for 2 hours under an Ar atmosphere, then raise the temperature to 500 °C and carbonize for 1 hour. Subsequently, disperse it in a mixed solution of 100 parts of Azo monomer and NIPAM, add 10 parts of Irgacure2959 to obtain a mixed solution. After irradiating the mixed solution with ultraviolet light at 365 nm for 30 minutes, centrifuge, wash, and freeze-dry to obtain SiO2@C@LDHs-PNIPAM-co-Azo;

[0068] S5. Immerse the SiO2@C@LDHs-PNIPAM-co-Azo in 2000 parts of p-aminobenzenesulfonic acid solution, oscillate for 24 hours, then centrifuge, wash, and dry to obtain the SiO2@LDHs nanocomposite with high adsorption efficiency.

[0069] Example 3

[0070] S1. Mix 934 parts of tetraethyl orthosilicate with 7890 parts of ethanol, ultrasonically disperse for 15 minutes, slowly add ammonia water until the pH value of the solution is 9, continuously stir for 2 hours, then successively add 14.1 parts of 3-aminopropyltrimethoxysilane and 5.25 parts of 3-mercaptopropyltrimethoxysilane. After stirring at room temperature for 2 hours, centrifuge, wash, and vacuum dry at 60 °C to obtain SiO2NH2 / SH;

[0071] S2. Dissolve 1200 parts of Mg(NO3)2·6H2O, 800 parts of Al(NO3)3·9H2O, 500 parts of chitosan and 150 parts of F127 in deionized water, ultrasonically disperse for 15 minutes, then add NaOH solution until the solution pH = 10, transfer the solution to a microchannel reactor, and treat it at 180 °C and a flow rate of 10 mL / min for 5 minutes. After cooling, centrifuge and wash to obtain a precursor suspension;

[0072] S3. Put the SiO2NH2 / SH into the precursor suspension and ultrasonically disperse for 30 minutes. After adding NaOH solution to adjust the pH to 10, treat the solution in a microwave continuous flow reactor at 180 °C for 5 minutes. After centrifuging and drying, deposit 10 cycles of Al2O3 layer on the surface by atomic layer deposition to obtain SiO2@LDHs;

[0073] S4. Carbonize the SiO2@LDHs in an Ar atmosphere at 350 °C for 2 hours, then raise the temperature to 500 °C and carbonize for 1 hour. Subsequently, disperse it in a mixed solution of 50 parts of Azo monomer and NIPAM, add 5 parts of Irgacure2959 to obtain a mixed solution. After irradiating the mixed solution with ultraviolet light of 365 nm for 30 minutes, obtain SiO2@C@LDHs-PNIPAM-co-Azo after centrifuging, washing and freeze-drying;

[0074] S5. Immerse the SiO2@C@LDHs-PNIPAM-co-Azo in 1730 parts of p-aminobenzenesulfonic acid solution, oscillate for 24 hours, and then obtain the SiO2@LDHs nanocomposite with high adsorption efficiency after centrifuging, washing and drying.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A preparation method of a SiO2@LDHs nanocomposite with high adsorption efficiency, characterized in that, The steps of the preparation method include: Mix tetraethyl orthosilicate with ethanol and conduct the first dispersion. Add ammonia water until the pH value of the solution is 9, and then successively add 3-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane, and conduct the first mixing to obtain SiO2NH2 / SH; Dissolve Mg(NO3)2·6H2O, Al(NO3)3·9H2O, chitosan and F127 in water, conduct the second dispersion, and then add NaOH solution until the pH of the solution = 10, and then conduct the first treatment to obtain a precursor suspension; Put the SiO2NH2 / SH into the precursor suspension for the third dispersion, add NaOH solution to adjust the pH to 10, and then conduct the second treatment to obtain SiO2@LDHs; Conduct carbonization treatment on the SiO2@LDHs, then disperse it in a mixed solution of Azo monomer and NIPAM, add a photoinitiator to obtain a mixed solution, and conduct ultraviolet irradiation treatment and post-treatment on the mixed solution to obtain SiO2@C@LDHs-PNIPAM-co-Azo; Soak the SiO2@C@LDHs-PNIPAM-co-Azo in p-aminobenzenesulfonic acid solution, and successively conduct oscillation, centrifugation, washing and drying to obtain the SiO2@LDHs nanocomposite with high adsorption efficiency.

2. The preparation method of the SiO2@LDHs nanocomposite with high adsorption efficiency according to claim 1, characterized in that The first dispersion, the second dispersion and the third dispersion are all ultrasonic dispersions, and the dispersion times are 15 minutes, 15 minutes and 30 minutes in sequence.

3. The preparation method of the SiO2@LDHs nanocomposite with high adsorption efficiency according to claim 1, characterized in that The first treatment is: transfer the solution to a microchannel reactor, and treat it at 180°C with a flow rate of 10 mL / min for 5 minutes, and then centrifuge and wash after cooling.

4. The preparation method of the SiO2@LDHs nanocomposite with high adsorption efficiency according to claim 1, characterized in that The second treatment is specifically: treat the solution in a microwave continuous flow reactor at 180°C for 5 minutes, centrifuge and dry it, and then deposit 10 cycles of Al2O3 layers on the surface by atomic layer deposition.

5. The preparation method of the SiO2@LDHs nanocomposite with high adsorption efficiency according to claim 1, characterized in that The carbonization treatment is to carbonize the SiO2@LDHs at 350°C for 2 hours in an Ar atmosphere, and then raise the temperature to 500°C and carbonize for 1 hour.

6. The preparation method of the SiO2@LDHs nanocomposite with high adsorption efficiency according to claim 1, characterized in that The ultraviolet irradiation treatment is: irradiate the mixed solution with ultraviolet light of 365 nm for 30 minutes; The post-treatment is specifically: centrifuge, wash and freeze-dry the mixed solution after irradiation is completed.

7. The preparation method of the SiO2@LDHs nanocomposite with high adsorption efficiency according to claim 1, characterized in that, The oscillation time is 24 hours.

8. The preparation method of the SiO2@LDHs nanocomposite material with high adsorption efficiency according to claim 1, characterized in that After the first mixing is completed, the obtained SiO2NH2 / SH is centrifuged, washed, and dried in sequence.

9. The preparation method of the SiO2@LDHs nanocomposite material with high adsorption efficiency according to claim 1, characterized in that The mass ratio of the Azo monomer to NIPAM in the Azo monomer and NIPAM mixed solution is 5:

45.

10. A SiO2@LDHs nanocomposite with high adsorption efficiency, characterized in that, It is prepared by the preparation method of the SiO2@LDHs nanocomposite material with high adsorption efficiency according to any one of claims 1-9.

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