A composite porous material, its preparation method and application

Abstract

This invention relates to the field of polymer materials technology, and particularly to a composite porous material, its preparation method, and its application. The preparation method includes the following steps: S1. Sodium hydroxide, tetraethyl orthosilicate, tetrapropylammonium hydroxide, template agent 1, and water are mixed and stirred. NaAlO2 is added and stirred to obtain a gel. The gel is transferred to a reaction vessel, crystallized in an oven, and then calcined at high temperature to obtain a core-structured material; S2. Template agent 2 is added to an aqueous solution of alcohol, followed by a pore-expanding agent, and stirred. The core-structured material is then added, and after sonication, tetraethyl orthosilicate and 1,2-bis(triethoxysilane)ethane are added and stirred to obtain an intermediate; S3. The intermediate is calcined at high temperature to obtain the composite porous material. The purpose is to give the composite porous material a vertical core-shell structure with variable pore size distribution, as well as a good heterogeneous open-pore structure, thereby enabling the composite porous material to have better performance when loading enzymes, fragrances, or adsorbing volatile gases.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a composite porous material, its preparation method, and its application. Background Technology

[0002] With rising living standards and increasing demands for health and taste, consumers are becoming more discerning in their cigarette choices. To meet these diverse needs, cigarette manufacturers are constantly developing various types of cigarette products. While adding flavorings and additives can effectively improve the smoking experience and impart specific characteristics to cigarettes, this method has limitations due to its involvement in the combustion process, making it difficult to fully utilize the fresh and natural aroma characteristics of natural flavorings. Adding functional substances with specific aroma / flavor characteristics to filter rods has gradually become a more promising method for aroma compensation, complementing the flavoring and additive process in cigarettes.

[0003] To address this, tobacco industry professionals employ methods such as adsorbents and flavoring threads to enhance the flavor and aroma of cigarette filters, aiming to improve the sensory quality of cigarettes. While the commonly used adsorbent and flavoring thread methods can, to some extent, modify and improve the flavor through the volatilization of aroma into the mainstream smoke during inhalation, they suffer from uneven release with each puff and loss of aroma substances over extended storage time, leading to unstable product quality. Some researchers have incorporated flavor-loaded functional tobacco particles encapsulated in polymer membranes into cigarette filters, allowing consumers to experience the released aroma during inhalation. However, given the inherent stability of polymer membranes, the coating is difficult to completely break down as mainstream smoke passes through, limiting the controllable release of tobacco flavor.

[0004] Chinese Patent CN201310611490.4 discloses a microporous core-shell composite molecular sieve for reducing harmful components in cigarette smoke and its preparation method. The preparation method includes the following steps: adding a template agent to a solution with an alcohol-to-water ratio of 1:1 to 4:3, then adding zeolite molecular sieves, ultrasonically dispersing for 0.5 to 2 hours, adding 1 to 1.5 times the mass of the zeolite molecular sieve to the zeolite molecular sieve dropwise, stirring at room temperature for 24 to 48 hours, and extracting the template agent with ethanol at room temperature to obtain the mesoporous-microporous core-shell composite molecular sieve material. In this invention, the template agent is directly extracted with ethanol, eliminating the need for high-temperature calcination, making the preparation process simpler. It has simple operation and equipment requirements, is inexpensive, and has good application prospects. The microporous core-shell composite molecular sieve, when applied to binary composite filter rods, has a significant adsorption effect on harmful substances, especially phenol, in cigarette smoke. However, during subsequent use, the inventors discovered that the pore size distribution and shell thickness in the core-shell structure of the molecular sieve material were not easy to adjust, which limited its application in different types of cigarettes. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a composite porous material, its preparation method and application, so that the composite porous material has a core-shell structure with vertical and variable pore size distribution, and also has a good heterogeneous open pore structure, thereby enabling the composite porous material to have better performance when loading enzymes, loading fragrances or adsorbing volatile gases.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] A method for preparing a composite porous material includes the following steps:

[0008] S1. Sodium hydroxide, tetraethyl orthosilicate, tetrapropylammonium hydroxide, template agent 1 and water are mixed and stirred until tetraethyl orthosilicate is fully hydrolyzed. Then NaAlO2 is added and stirred to obtain a gel. The gel is transferred to a reaction vessel and crystallized in an oven at 130°C for 72 hours. Then it is calcined at high temperature to obtain the core structure material.

[0009] S2. Add template agent 2 to an aqueous solution of alcohol, then add pore-expanding agent, stir for 2-3 hours, then add the core structure material from step S1, sonicate for 0.5-2 hours, then add tetraethyl orthosilicate and 1,2-bis(triethoxysilane)ethane, and stir at 30-40°C for 24-48 hours to obtain the intermediate.

[0010] S3. After calcining the intermediate at high temperature or extracting it with ethanol at 60°C for 6-12 hours, a core-shell composite porous material is obtained.

[0011] Based on the above technical means, a core-shell structure with vertical and variable pore size distribution can be prepared, which also has a good heterogeneous open-pore structure and adjustable shell thickness, thereby making the porosity adjustable. This allows the core-shell composite porous material to have a "multi-level channel" with micropores and mesopores coexisting, which has better effects when loading enzymes, loading fragrances, or adsorbing volatile gases.

[0012] Preferably, in step S1, the mass ratio of sodium hydroxide, tetraethyl orthosilicate and tetrapropylammonium hydroxide is 1:(2-2.5):(80-82).

[0013] Preferably, in step S1, template agent 1 is one or more of citric acid, dodecylamine, and tetradecylamine.

[0014] More preferably, template agent 1 is citric acid.

[0015] Preferably, in step S2, the template agent 2 is one of tetradecylamine and hexadecylamine, and the pore-expanding agent is mesitylene.

[0016] Further preferably, template agent 2 is tetradecylamine.

[0017] Preferably, in step S2, the alcohol is one of ethanol, n-propanol, and isopropanol, and the ratio of alcohol to water in the aqueous solution of the alcohol is (1.5-2):1.

[0018] Preferably, in steps S1 and S3, during high-temperature calcination, an air atmosphere is used for high-temperature calcination, with the temperature increased to 350°C at 5-10°C / min and held for 30 minutes, and then the temperature increased to 550°C at 1-5°C / min and held for 2-3 hours.

[0019] Preferably, in step S2, the mass ratio of 1,2-bis(triethoxysilane)ethane to the core structure material is 1:(1-1.5).

[0020] This application also discloses a composite porous material prepared by the preparation method described above.

[0021] Preferably, the thickness of the shell in the composite porous material is 20-90 nm.

[0022] This application also discloses an application of a composite porous material, which is used to load enzymes, load fragrances, or adsorb volatile gases.

[0023] The present application, employing the above-described scheme, has the following beneficial effects:

[0024] 1. By using organosilicon emulsification and citric acid as a template agent and organosilicon as a sacrificial template agent during the preparation of nuclear structure materials, the mesopore size in the nuclear structure materials can be adjusted after high-temperature calcination, thereby obtaining nuclear structure materials with larger and more abundant pore sizes.

[0025] 2. By using treated core-structured materials and combining them with different alcohol-to-water ratios, tetradecylamine, and pore-expanding agents, the thickness of the silicon shell can be controlled after reacting with tetraethyl orthosilicate and 1,2-bis(triethoxysilane)ethane. This allows the resulting composite porous material to have a vertical core-shell structure with variable pore size distribution, as well as a good heterogeneous open-pore structure. This enables the composite porous material to have better performance when loading enzymes, flavorings, or adsorbing volatile gases, making it suitable for different types of cigarettes. Attached Figure Description

[0026] This application can be further illustrated by the non-limiting embodiments given in the accompanying drawings;

[0027] Figure 1 This is the XRD pattern of the composite porous material in the embodiments of this application;

[0028] Figure 2This is one of the electron microscope images of the composite porous material in the embodiments of this application;

[0029] Figure 3 This is the second electron microscope image of the composite porous material in the embodiments of this application;

[0030] Figure 4 This is an adsorption-desorption curve of the composite porous material in the embodiments of this application;

[0031] Figure 5 This is a pore size distribution diagram of the composite porous material in the embodiments of this application;

[0032] Figure 6 These are the adsorption curves and kinetic curves of the composite porous material for n-butyraldehyde in the embodiments of this application;

[0033] Figure 7 These are the adsorption curves and kinetic curves of benzene on the composite porous material in the embodiments of this application. Detailed Implementation

[0034] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification:

[0035] Example 1, Preparation of composite porous materials

[0036] S1. Mix 0.4g sodium hydroxide, 1.0g tetraethyl orthosilicate, 32.8g tetrapropylammonium hydroxide (TAPOH, 25% aqueous solution), (0.010-0.030mol) citric acid and 59.6g water and stir until the tetraethyl orthosilicate is fully hydrolyzed. Then add 0.4g NaAlO2 and stir to obtain a gel. Transfer the gel to a reaction vessel and crystallize it in an oven at 130℃ for 72 hours. Then calcine it at high temperature in an air atmosphere by raising the temperature to 350℃ at 5-10℃ / min and holding it for 30 min. Then raise the temperature to 550℃ at 1-5℃ / min and hold it for 2-3 h to obtain ZSM-5 core structure material.

[0037] S2. Add tetradecylamine to a solution with an alcohol-to-water ratio of (1.5-2):1, then add mesitylene, and stir at 300-400 rpm for 2-3 h. Then add the ZSM-5 material obtained in step S1, and sonicate for 0.5-2 h. After sonication, add 1.0 times the amount of tetraethyl orthosilicate of ZSM-5 and 0.1 times the amount of 1,2-bis(triethoxysilane)ethane of ZSM-5, and stir at 30-40℃ for 24-48 h to obtain the intermediate.

[0038] S3. The intermediate is calcined at high temperature in an air atmosphere, heated to 350℃ at 5-10℃ / min and held for 30 min, and then heated to 550℃ at 1-5℃ / min and held for 2-3 h, or the intermediate is directly extracted with ethanol at 60℃ for 6-12 h to obtain a core-shell structured composite porous material.

[0039] Example 2, Preparation of composite porous materials

[0040] S1. Mix 0.4g sodium hydroxide, 1.0g tetraethyl orthosilicate, 32.8g tetrapropylammonium hydroxide (TAPOH, 25% aqueous solution), (0.010-0.030mol) citric acid and 59.6g water and stir until the tetraethyl orthosilicate is fully hydrolyzed. Then add 0.4g NaAlO2 and stir to obtain a gel. Transfer the gel to a reaction vessel and crystallize it in an oven at 130℃ for 72 hours. Then calcine it at high temperature in an air atmosphere by raising the temperature to 350℃ at 5-10℃ / min and holding it for 30 min. Then raise the temperature to 550℃ at 1-5℃ / min and hold it for 2-3 h to obtain ZSM-5 core structure material.

[0041] S2. Add tetradecylamine to a solution with an alcohol-to-water ratio of (1.5-2):1, then add mesitylene, and stir at 300-400 rpm for 2-3 hours. Then add the ZSM-5 material from step S1, and sonicate for 0.5-2 hours. After sonication, add 1.2 times the amount of tetraethyl orthosilicate of ZSM-5 and 0.1 times the amount of 1,2-bis(triethoxysilane)ethane of ZSM-5, and stir at 30-40°C for 24-48 hours to obtain the intermediate.

[0042] S3. The intermediate is calcined at high temperature in an air atmosphere, heated to 350℃ at 5-10℃ / min and held for 30 min, and then heated to 550℃ at 1-5℃ / min and held for 2-3 h, or the intermediate is directly extracted with ethanol at 60℃ for 6-12 h to obtain a core-shell structured composite porous material.

[0043] Example 3, Preparation of Composite Porous Materials

[0044] S1. Mix 0.4g sodium hydroxide, 1.0g tetraethyl orthosilicate, 32.8g tetrapropylammonium hydroxide (TAPOH, 25% aqueous solution), (0.010-0.030mol) citric acid and 59.6g water and stir until the tetraethyl orthosilicate is fully hydrolyzed. Then add 0.4g NaAlO2 and stir to obtain a gel. Transfer the gel to a reaction vessel and crystallize it in an oven at 130℃ for 72 hours. Then calcine it at high temperature in an air atmosphere by raising the temperature to 350℃ at 5-10℃ / min and holding it for 30 min. Then raise the temperature to 550℃ at 1-5℃ / min and hold it for 2-3 h to obtain ZSM-5 core structure material.

[0045] S2. Add tetradecylamine to a solution with an alcohol-to-water ratio of (1.5-2):1, then add mesitylene, and stir at 300-400 rpm for 2-3 h. Then add the pretreated ZSM-5 from step S1, and sonicate for 0.5-2 h. After sonication, add 1.5 times the amount of tetraethyl orthosilicate of ZSM-5 and 0.1 times the amount of 1,2-bis(triethoxysilane)ethane of ZSM-5, and stir at 30-40℃ for 24-48 h to obtain the intermediate.

[0046] S3. The intermediate is calcined at high temperature in an air atmosphere, heated to 350℃ at 5-10℃ / min and held for 30 min, and then heated to 550℃ at 1-5℃ / min and held for 2-3 h, or the intermediate is directly extracted with ethanol at 60℃ for 6-12 h to obtain a core-shell structured composite porous material.

[0047] The composite porous materials prepared in Examples 1-3 were characterized by XRD, and the characterization results are as follows: Figure 1 As shown. Among them, (a) ZSM-5, (b) ZSM-5@SiO2-20, (c) ZSM-5@SiO2-40, (d) ZSM-5@SiO2-70, (e) ZSM-5@SiO2-90. From... Figure 1 It can be seen that the original ZSM-5 exhibits typical standard diffraction peaks of MFI type zeolites ( Figure 1 -a) Core-shell composite materials also exhibit similar diffraction peaks, indicating that the coating process using long-chain organic amines (tetradecylamine or hexadecylamine) as templates has almost no effect on the core-shell structure. However, the diffraction peak intensity of core-shell composite porous materials decreases continuously with the increase of the coating shell thickness. This is because the silicon shell obtained through coating acts as a shield, and the dilution of the molecular sieve also leads to a decrease in diffraction peak intensity.

[0048] The composite porous materials prepared in Examples 1-3 were then subjected to electron microscopy scanning, and the results are as follows: Figure 2As shown. Among them, (a)(b)ZSM-5, (c)(d)ZSM-5@SiO2-20, (e)(f)ZSM-5@SiO2-40, (g)(h)ZSM-5@SiO2-70, (i)(j)ZSM-5@

[0049] SiO2-90. (The last part appears to be a fragment and doesn't translate directly.) Figure 2 It can be seen that ZSM-5 with an average particle size of around 300 nm has good dispersibility, exhibits a prismatic shape, and has a relatively rough surface. Figure 2 -a,2-b), this is a typical characteristic morphology of MIF molecular sieves. After constructing a mesoporous silica shell using long-chain organic amines as templates, the composite porous material (ZSM-5@SiO2) with a core-shell structure becomes rougher and has more rounded edges compared to the original ZSM-5 molecular sieve. Figure 2 -c), but still maintains good dispersion and uniformity ( Figure 2 -d). In addition, when the ratio of TEOS (tetraethyl orthosilicate) to ZSM-5 is less than 1:1.2, the "wrinkles" of the resulting composite molecular sieve gradually decrease until the surface becomes rounded; as TEOS increases further (TEOS / ZSM-5 = 1:1.5), the composite molecular sieve exhibits a "wrinkled" morphology, that is, a large number of divergent channels appear.

[0050] Further scanning was performed on the composite porous materials prepared in Examples 1-3, and the results are as follows: Figure 3 As shown. Among them, (a)(b) ZSM-5@SiO2-20, (c)(d) ZSM-5@SiO2-40, (e)(f) ZSM-5@SiO2-70, (g)(h) ZSM-5@SiO2-90. From... Figure 3 It can be seen that ZSM-5@SiO2 has a uniform core-shell composite porous structure. Figure 3 -a), and the thickness of the mesoporous silicon shell can be controlled by changing the ratio of TEOS / ZSM-5 by 20 nm. Figure 3 -b) to 90nm ( Figure 3 The results (-h) indicate that a core-shell composite porous material was successfully synthesized using organic amines as templates, and the shell thickness can be controlled. When the TEOS / ZSM-5 ratio is less than 1:1.2, high-resolution TEM images show that although the channels in the mesoporous silica shell are somewhat tortuous, they still have good uniformity and are nearly perpendicularly distributed on each crystal plane of ZSM-5. Furthermore, as the TEOS ratio increases further (TEOS / ZSM-5 = 1:1.5), divergent channels form on the ZSM-5 crystal surface, with large variations in channel tortuosity and uneven pore size distribution, but the shell channels remain generally perpendicular to each crystal plane of ZSM-5. High-magnification transmission electron microscopy images ( Figure 3The (-d,f,h) further demonstrates that the molecular sieve framework of MIF and the mesoporous silica shell are tightly bonded together at their junctions, indicating that the structure of the combination of micropores and mesopores with relative openness is very important for heterogeneous core-shell structures.

[0051] Example 4, Adsorption Test

[0052] The N2 adsorption and desorption of ZSM-5 and ZSM-5@SiO2 samples were measured using an adsorption-desorption apparatus. The test results are as follows: Figure 4 As shown, (a) ZSM-5, (b) ZSM-5@SiO2-20, (c) ZSM-5@SiO2-40, (d) ZSM-5@SiO2-70, and (e) ZSM-5@SiO2-90. (The text appears to be incomplete and requires further context.) Figure 4 It is known that the original ZSM-5 ( Figure 4 a) A sharp upward curve (typical Type I) appears at relatively low pressure (P / P0), which is typical of microporous structures. Furthermore, a hysteresis loop with a small amount of mesopore formation appears at P / P0 = 0.5-0.98. After coating with a mesoporous silicon shell, ZSM-5@SiO2-X shows a similar Type I curve to ZSM-5 at relatively low pressure and a more pronounced capillary condensation change (typical Type IV curve) at P / P0 = 0.3-0.5. This H2 hysteresis loop formation is caused by mesopores. This indicates that the dual-pore performance from micropores to mesopores is consistent with the core-shell structure in the TEM images. Furthermore, when the core-shell thickness increases to 70 nm, the core-shell composite material (… Figure 4 c) exhibits similar curve changes, but the hysteresis loop becomes more pronounced in the 0.3–0.5 range, further indicating the material's dual-channel structure and tunable shell thickness. The difference lies in the fact that when the core-shell thickness increases to 90 nm, the core-shell composite porous material (… Figure 4 e) The curve changes significantly, with the hysteresis loop becoming 0.4-0.9, indicating that the material has a larger pore structure.

[0053] The samples were then analyzed using an adsorption-desorption instrument. The pore size distribution was obtained based on the analysis data, as shown in Figure 5. The pore sizes are: (a) ZSM-5, (b) ZSM-5@SiO2-20, (c) ZSM-5@SiO2-40, (d) ZSM-5@SiO2-70, and (e) ZSM-5@SiO2-90. Figure 5 It is known that the original ZSM-5 has micropores of 0.56 nm and some mesopores, but micropores are predominant. Core-shell composites with different silicon shell thicknesses show two pore distributions: original micropores of 0.56 nm and mesopores of 3.4 nm. Figure 5 The values ​​at b and c (i.e., b and c at 11 nm) further demonstrate the coexistence of micropores and mesopores, and that the mesopore size distribution is relatively uniform; while ( Figure 5 e) The observed mesopore distribution is relatively broad, showing a main peak at 3.4 nm, with pores distributed throughout the 5-30 nm range, forming relatively diffuse channels. These results demonstrate that, through the use of template agents and the regulation of TEOS / ZSM-5, a core-shell structure with a vertical pore size distribution can be obtained.

[0054] Then, the adsorption curves and kinetic curves of n-butyraldehyde and benzene were tested on ZSM-5 and ZSM-5@SiO2-90. The test results are as follows: Figure 6-7 As shown, where, Figure 6 The adsorption and kinetic curves for n-butyraldehyde are shown. Figure 7 The images show the adsorption and kinetic curves for benzene. Figure 6-7 It can be seen that for the adsorption curves of n-butyraldehyde and benzene of ZSM-5, the adsorption capacity increases continuously with the increase of P / P0, with a significant increase in the relatively low pressure stage (P / P0≤0.06), indicating that microporous adsorption is dominant. For ZSM-5@SiO2-90, the curve maintains a sharp increase in the low pressure stage. However, unlike ZSM-5, the adsorption curve shows a significant rapid increase in the high pressure stage (even exceeding P / P0≤0.80), further indicating that the core-shell composite porous material has a "multi-level pore" characteristic with coexistence of micropores and mesopores. The adsorption capacity of the original molecular sieve ZSM-5 for n-butyraldehyde and benzene in the measured relative pressure range was 134.7 mg.g. -1 and 99.2 mg.g -1 After coating with mesoporous silica, the adsorption capacities of ZSM-5@SiO2-90 for n-butyraldehyde and benzene increased to 199.4 mg / g, respectively. -1 (Adsorption capacity increased by 48.0%) and 156.9 mg.g -1 (The adsorption capacity increased by 58.2%), mainly due to the contribution of shell mesoporous adsorption, which is consistent with the nitrogen adsorption results.

[0055] The kinetic diffusion coefficient of n-butyraldehyde molecules in the core-shell composite porous material ZSM-5@SiO2-90 was calculated to be 1.02 × 10⁻⁶ using the gravimetric adsorption isotherm. -6 cm 2 .s -1 It is slightly lower than the molecular diffusion coefficient of butyraldehyde in ZSM-5 (1.09×10⁻⁶). -6 cm 2 .s -1 Similarly, the kinetic diffusion coefficient of benzene molecules in the core-shell composite porous material ZSM-5@SiO2-90 was calculated to be 9.57 × 10⁻⁶ using benzene gravimetric adsorption isotherms. -7 cm 2 .s -1 It is slightly smaller than the diffusion coefficient of benzene molecules in ZSM-5 (1.50 × 10⁻⁶).-6 cm 2 .s -1 However, the results all indicate that after coating, ZSM-5 has little impact on the diffusion coefficient of kinetics, and the obtained core-shell structure ZSM-5@HMS maintains a high degree of porosity.

[0056] The composite porous materials prepared in Examples 1-3 were then subjected to property tests. N2 adsorption-desorption tests were conducted at 77K using an ASAP2020 surface area analyzer. Each sample was degassed under vacuum at 300℃ for 15 hours before the test. The test results are shown in the table below:

[0057]

[0058] Among them, S BET S represents the total specific surface area. micro S represents the specific surface area of ​​micropores. ex V represents the specific surface area of ​​micropores and the specific surface area of ​​mesopores. micro V represents the pore volume of micropores. ex V represents the mesopore volume. t Indicates the total orifice volume.

[0059] The data above shows that the specific surface area and pore volume of ZSM-5 are 335 m². 2 .g -1 and 0.21cm 3 .g -1 Approximately 201m 2 .g -1 (60.0%) and 0.12cm 3 .g -1 The pores originated from micropores, with the remainder from mesopores. This is attributed to the addition of a small amount of template agent (citric acid) during the synthesis of ZSM-5. After coating with a 70 nm mesoporous silica shell, the specific surface area and pore volume increased to 534 m². 2 .g -1 and 0.40cm 3 .g -1 Approximately 424m 2 .g -1 and 0.37cm 3 .g -1 The main contribution comes from mesopores. Furthermore, as the shell thickness increases to 90 nm, its specific surface area increases to 528 m². 2 .g -1 The shell size decreased compared to 70nm, while the pore volume continued to increase to 0.47cm. 3 .g -1 The increased specific surface area (443m²) 2 .g -1 ) and pore volume (0.45cm)3 .g -1 The contribution from mesopores is consistent with the pore size distribution described above. These results indicate that the mesopore / micropore porosity of the composite material can be adjusted by the shell thickness, with the decrease in micropore porosity as the shell thickness increases primarily due to the reduction in zeolite content in the composite porous material.

[0060] In summary, the composite porous material prepared in this application has a vertical core-shell structure with variable pore size distribution, as well as a good heterogeneous open-pore structure. This allows the composite porous material to have better performance when loading enzymes, flavorings, or adsorbing volatile gases, which is conducive to the diffusion of gas molecules from mesopores to micropores. At the same time, it has a larger specific surface area, which is more conducive to the capture of harmful gas molecules. Therefore, it can be more widely used in different types of cigarettes (such as traditional cigarettes with reduced harm, and new tobacco flavorings).

[0061] The above provides a detailed description of the composite porous material, its preparation method, and its applications provided by the present invention. The specific embodiments are provided only to aid in understanding the method and core concepts of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0062] It should be noted that: for experimental steps or conditions not specified in the examples, the procedures and conditions described in conventional experimental procedures in the literature of this art can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0063] The above examples are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by anyone under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

Claims

1. A method for preparing a composite porous material, characterized in that, Includes the following steps: S1. Sodium hydroxide, tetraethyl orthosilicate, tetrapropylammonium hydroxide, template agent 1 and water are mixed and stirred until tetraethyl orthosilicate is fully hydrolyzed. Then NaAlO2 is added and stirred to obtain a gel. The gel is transferred to a reaction vessel and crystallized in an oven at 130°C for 72 hours. Then it is calcined at high temperature to obtain the core structure material. The template agent 1 is citric acid. S2. Add template agent 2 to an aqueous solution of alcohol, then add a pore-expanding agent, stir for 2-3 hours, then add the core structure material from step S1, sonicate for 0.5-2 hours, then add tetraethyl orthosilicate and 1,2-bis(triethoxysilane)ethane, stir at 30-40°C for 24-48 hours to obtain an intermediate; the template agent 2 is one of tetradecylamine and hexadecylamine; S3. After calcining the intermediate at high temperature or extracting it with ethanol at 60°C for 6-12 hours, a core-shell composite porous material is obtained.

2. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of sodium hydroxide, tetraethyl orthosilicate, and tetrapropylammonium hydroxide is 1:(2-2.5):(80-82).

3. The preparation method according to claim 1, characterized in that, In step S2, the pore-expanding agent is mesitylene.

4. The preparation method according to claim 1 or 3, characterized in that, In step S2, the alcohol is one of ethanol, n-propanol, and isopropanol, and the ratio of alcohol to water in the aqueous solution of the alcohol is (1.5-2):

1.

5. The preparation method according to claim 4, characterized in that, In steps S1 and S3, during high-temperature calcination, an air atmosphere is used for high-temperature calcination. The temperature is increased to 350°C at a rate of 5-10°C / min and held for 30 minutes. Then, the temperature is increased to 550°C at a rate of 1-5°C / min and held for 2-3 hours.

6. The preparation method according to claim 1, characterized in that, In step S2, the mass ratio of 1,2-bis(triethoxysilane)ethane to the nuclear structure material is 1:(1-1.5).

7. A composite porous material, characterized in that, It is prepared by the preparation method described in any one of claims 1-6.

8. A composite porous material according to claim 7, characterized in that, In the composite porous material, the thickness of the shell is 20-90 nm.

9. An application of the composite porous material as described in claim 7, characterized in that, The composite porous material is used to load enzymes, fragrances, or adsorb volatile gases.

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