Method for preparing silicon dioxide composite material

Abstract

The invention belongs to the technical field of silicon dioxide, and particularly relates to a method for preparing a silicon dioxide composite material, which comprises the following steps: adding silicon dioxide microspheres or a silicon dioxide mixture into a chitosan solution, adding a PEI aqueous solution, stirring for reaction, adding a glutaraldehyde solution, stirring for reaction to obtain a gelatinous product, and drying to obtain the silicon dioxide composite material. Wherein the silicon dioxide mixture comprises a silicon dioxide sponge spicule mixture, and the silicon dioxide sponge spicule mixture is prepared by adding a sponge spicule into silicon dioxide sol. The preparation process of the silicon dioxide composite material is simplified, and the synergistic effect of silicon dioxide and the matrix is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of silicon dioxide, and particularly relates to a method for preparing a silicon dioxide composite material. Background Art

[0002] As a common inorganic material, silica has a wide range of applications in catalysis, adsorption, drug purification, chromatographic separation, composite material preparation and other fields due to its chemical stability, thermal stability, biocompatibility and high specific surface area.

[0003] In the field of composite materials, while single silica microspheres possess certain functionality, their applications are often limited. For example, silica microspheres have a low density of adsorption sites and are prone to agglomeration, resulting in a decrease in effective surface area. Furthermore, the preparation of composite materials is complex, involving multiple reactions and interface manipulation. Achieving synergistic effects between silica and the matrix remains a challenge in current research. Summary of the Invention

[0004] The present invention addresses the deficiencies of the prior art and provides a method for preparing a silicon dioxide composite material.

[0005] The technical solutions of the present invention are as follows: In a first aspect, the present invention provides a method for preparing silica microspheres, comprising the following steps: Anhydrous ethanol, TEOS, and PEG are mixed and cooled to obtain solution A; an ammonia solution is cooled to obtain solution B; solution B is added dropwise to solution A while stirring, and the mixture is stirred for reaction; after the reaction, the mixture is centrifuged twice and dried to obtain silica microspheres.

[0006] It should be noted that in the prior art, nano-sized silica particles have high surface energy and are prone to agglomeration, resulting in a decrease in effective specific surface area. This application effectively inhibits agglomeration through low-temperature preparation, PEG stabilizer, and freeze-drying technology, significantly improving dispersibility and specific surface area.

[0007] In one embodiment, the method of centrifuging twice after the reaction includes the following steps: transferring the reaction solution to a centrifuge tube, centrifuging at 10,000-15,000 rpm, discarding the supernatant, adding a small amount of pre-cooled anhydrous ethanol, ultrasonically dispersing, centrifuging again at 10,000-15,000 rpm, and washing.

[0008] In a second aspect, the present invention provides a method for preparing a silica sponge spicule mixture, comprising the following steps: adding the sponge spicules into an acid solution, stirring, and drying to obtain dried sponge spicules; Adding APTES to anhydrous ethanol to obtain an APTES ethanol solution; The dried sponge spicules were added into an APTES ethanol solution, stirred, and dried to obtain modified sponge spicules; Anhydrous ethanol, TEOS, and PEG are mixed and cooled to obtain solution A; an ammonia solution is cooled to obtain solution B; solution B is added dropwise to solution A while stirring, and the mixture is stirred to react; after the reaction, silica sol is obtained; The modified sponge spicules are added to the silica sol, mixed, and allowed to stand to obtain a gelled sol; the gelled sol is further allowed to stand for aging, and dried after aging to obtain a silica sponge spicule mixture.

[0009] In one embodiment, the concentration of APTES in the APTES ethanol solution is 0.5-2%.

[0010] In the first aspect and the second aspect, preferably, the cooling temperature is -30~0°C.

[0011] It should be noted that existing methods for preparing silica microspheres are typically performed at room temperature or higher temperatures, resulting in a rapid reaction rate and difficulty in precisely controlling the particle size and dispersion. This results in uneven particle size distribution and limited specific surface area, which in turn limits their application in high-performance composite materials. Unlike existing methods, this application chooses to prepare silica microspheres at low temperatures.

[0012] Preferably, when solution B is added dropwise to solution A while stirring, the dropping speed is 0.01-0.2 mL / min.

[0013] Preferably, the solid-liquid ratio of PEG to anhydrous ethanol and TEOS is 0.05-0.10 g:90-110 mL:0.12-0.18 mL.

[0014] In a third aspect, the present invention provides a method for preparing a silicon dioxide composite material, comprising the following steps: Adding silica microspheres or a silica mixture to a chitosan solution, adding a PEI aqueous solution, stirring to react, adding a glutaraldehyde solution, stirring to react to obtain a gel product, and drying to obtain a silica composite material; The silica mixture includes a silica-sponge-bone spicule mixture, which is prepared by adding sponge spicules into silica sol.

[0015] Preferably, the silica microspheres are prepared by the first aspect, and the silica sponge-bone spicule mixture is prepared by the second aspect.

[0016] Preferably, the concentration of chitosan in the chitosan solution is 0.5-2%.

[0017] Preferably, the concentration of PEI in the PEI aqueous solution is 0.5-2%.

[0018] It should be noted that the PEI aqueous solution can be prepared from PEI and deionized water.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. Preparation of monodisperse silica microspheres High particle size uniformity: By controlling the hydrolysis and polycondensation rates of TEOS under low temperature reaction conditions and extremely low droplet acceleration, the nucleation and growth processes are slowed down to prepare monodisperse silica microspheres, thus avoiding rapid aggregation caused by excessive local concentration.

[0020] High surface area and activity: Low-temperature preparation effectively inhibits particle aggregation. Combined with the steric hindrance of PEG as a stabilizer, this significantly improves the dispersibility and specific surface area of ​​the silica microspheres, enhancing the exposure of active sites. Experimental results show that the monodisperse silica microspheres prepared in Example 1 significantly outperform existing silica (Comparative Example 2) in adsorption performance.

[0021] The process is highly controllable: low-concentration TEOS and ammonia water, a longer reaction time, and freeze-drying technology are used to ensure sufficient reaction and minimize particle agglomeration. The process is simple and easy to promote industrialization.

[0022] 2. Preparation of silica sponge spicule mixture Synergistic Effect of Hierarchical Porosity: Utilizing the natural hierarchical pore structure of sponge spicules as a template and carrier, a silica sol was prepared via a low-temperature sol-gel method. Combined with silane coupling modification of APTES, a three-dimensional network structure was formed on the surface and within the pores of the sponge spicules. Adsorption experiments confirmed that the silica-sponge-spicule mixture prepared in Example 2 combines the natural pores of the sponge spicules with the nanoporous structure of the silica gel, significantly increasing the specific surface area and adsorption site density.

[0023] Enhanced interfacial bonding: APTES, by introducing amino anchoring sites, strengthens the interfacial bonding between silica and sponge spicules, preventing nanoparticle shedding or aggregation. In adsorption tests, the adsorption capacity of Example 2 was significantly higher than that of Example 1, demonstrating the synergistic effect of the hierarchical pore structure and interface optimization.

[0024] Biocompatibility and functionality: Sponge spicules, as natural biomaterials, have good biocompatibility. Combined with the high specific surface area and chemical stability of silica, the mixture has potential application value in biomedicine, drug purification, chromatographic separation and other fields.

[0025] 3. Preparation of silica composite materials Construction of three-dimensional network structure: Through the cross-linking effect of chitosan, PEI and glutaraldehyde, a three-dimensional network structure with strong biocompatibility and excellent mechanical properties was constructed, and the silica sponge-bone needle mixture or monodisperse silica microspheres were encapsulated in it to form an organic-inorganic hybrid composite material.

[0026] Synergistic Effect of Multiple Adsorption Sites: The positively charged functionalization of chitosan and PEI introduces abundant hydroxyl and amino sites, which synergistically capture target molecules, such as molecules, through hydrogen bonding and electrostatic interactions with the amino groups modified with APTES. Glutaraldehyde crosslinking further enhances the stability of the network structure, preventing nanoparticle aggregation and maintaining accessibility of active sites.

[0027] Significantly Improved Adsorption Performance: In adsorption tests, Examples 3 and 4 both outperformed Comparative Examples 1 and 2, demonstrating that the silica materials prepared herein (whether sponge-bone spicule mixtures or monodisperse microspheres) exhibited higher adsorption capacity and rate when combined with chitosan / PEI. This is attributed to the synergistic effects of the hierarchical pore structure, high specific surface area, and multiple adsorption sites.

[0028] In summary, this application simplifies the preparation process of silica composite materials and enhances the synergistic effect between silica and the matrix. Furthermore, this application significantly improves the adsorption performance of the material by optimizing the preparation process of silica microspheres and constructing a silica sponge-bone spicule mixture with a hierarchical pore structure and silica composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 This is an electron microscope image of the monodisperse silica microspheres of the present invention; it should be noted that the relevant parameters are: EHT=5.00KV, WD=8.6mm, Signal A=SE2, Mag=1.00KX. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] In the prior art, nano-sized silica particles have high surface energy and are prone to agglomeration, even with the protection of a stabilizer. The present invention provides a new method for preparing silica particles to solve this problem.

[0033] The raw materials involved in the following: Tetraethyl orthosilicate: TEOS, ultrapure grade; Anhydrous ethanol: ultrapure grade; Ammonia: analytical grade; Polyethylene glycol: PEG 200, analytical grade; Sponge spicules: 99% purity, medical grade; Sodium hypochlorite: analytical grade; Hydrochloric acid: analytical grade; 3-Aminopropyltriethoxysilane: APTES, 98% purity; Chitosan: Deacetylation degree ≥85%, molecular weight 50-190 kDa, available from Sigma-Aldrich; PEI: Polyethyleneimine, branched type, molecular weight 1.8-10kDa.

[0034] The PEI aqueous solution can be prepared from PEI and deionized water, which is a conventional method.

[0035] Unless otherwise specified, the experimental methods used below are conventional methods, and the materials and reagents used are all commercially available unless otherwise specified.

[0036] Method 1: The preparation of monodisperse silica microspheres is as follows: Add 80-100 mL of anhydrous ethanol, 0.1-0.2 mL of TEOS, and 0.05-0.1 g of PEG200 to a low-temperature reaction container, stir magnetically until completely dissolved, and cool the solution to -20°C to obtain solution A.

[0037] Add 30-50 mL of deionized water and 0.05-0.1 mL of aqueous ammonia into the flask, stir evenly with a magnetic stirrer, and cool the solution to -20°C to obtain solution B.

[0038] Keep solution A in a low-temperature bath and slowly add solution B to solution A at 0.01 mL / min while magnetically stirring. After the addition is complete, continue stirring and reacting at low temperature for 24-48 hours.

[0039] The reaction solution was transferred to a cryogenically resistant centrifuge tube and centrifuged at high speed for 30-60 minutes. The supernatant was discarded, and a small amount of pre-cooled anhydrous ethanol was added. Ultrasonic dispersion was performed, and the mixture was centrifuged at high speed for another 30-60 minutes. The mixture was washed and freeze-dried to obtain monodisperse silica microspheres with a size of 20-5000 nm.

[0040] It should be noted that the present application utilizes low temperature to suppress the rapid hydrolysis and polycondensation of TEOS to prepare monodisperse silica microspheres.

[0041] This application 1) uses low temperatures to effectively inhibit the hydrolysis and polycondensation rates of TEOS, slowing the nucleation and growth processes and favoring the formation of small particles. 2) Uses low concentrations of TEOS and ammonia to reduce nucleation sites and prevent rapid aggregation. 3) Uses PEG as a stabilizer, which can adsorb on the surface of silica particles, providing steric hindrance and preventing particle agglomeration. To achieve this, a low molecular weight PEG is selected, making it more suitable for preparing ultra-small particles. 4) Uses an extremely low droplet addition rate to facilitate control of the particle size of the silica microspheres. Highly uniform microspheres promote monodispersity, avoid localized excessive concentrations, and promote uniform nucleation and growth. 5) This application has a long reaction time, and under low temperatures and extremely diluted conditions, the reaction rate is very slow. A longer reaction time ensures a sufficient reaction. 6) High-speed centrifugation is used to effectively separate small particles / microspheres. 7) This application selected freeze-drying from a variety of drying methods, as freeze-drying can minimize particle agglomeration.

[0042] The following is the specific implementation method 1: Example 1 Method 1 was used to prepare monodisperse silica microspheres. The specific steps were as follows: 100 mL of anhydrous ethanol, 0.15 mL of TEOS, and 0.07 g of PEG 200 were added to a low-temperature reaction container and magnetically stirred until completely dissolved. The solution was cooled to -20°C to obtain solution A.

[0043] 50 mL of deionized water and 0.08 mL of aqueous ammonia were added to the flask, the mixture was stirred evenly by magnetic stirring, and the solution was cooled to -20°C to obtain solution B.

[0044] Solution A was kept in a -20°C low-temperature bath and solution B was slowly added dropwise at 0.01 mL / min to solution A while magnetically stirring. After the addition was complete, the reaction was continued at -20°C with stirring for 36 hours.

[0045] The reaction solution was transferred to a cryogenic centrifuge tube and centrifuged at 15000 rpm for 45 minutes. The supernatant was discarded and 2-5 mL of pre-cooled -20°C anhydrous ethanol was added to completely cover the precipitate. Ultrasonic dispersion was performed and centrifuged at 15000 rpm for 45 minutes again. The solution was washed and freeze-dried to obtain 1000 nm monodisperse silica microspheres. The microstructure of the monodisperse silica microspheres can be observed by referring to Figure 1 The monodisperse silica microspheres have complete structure, good morphology, good dispersion and no agglomeration.

[0046] It should be noted that traditional sol-gel methods or the preparation of silica microspheres are typically performed at room temperature or higher temperatures. The low temperature employed in this experiment allows for better control over the formation and growth of sol particles, resulting in more uniform silica microspheres. The silica microspheres prepared at such low temperatures exhibit higher specific surface area and activity, potentially improving the performance of composite materials.

[0047] The following is a further study of related composite materials based on silica microspheres prepared at low temperature.

[0048] Example 2 Based on the method of method 1, a silica sponge spicule mixture was prepared, and the specific steps were as follows: Activation: Add 10 g of sponge spicules to 100 mL of 1 M hydrochloric acid solution and stir at room temperature for 1 hour. Wash repeatedly with deionized water until neutral, and dry in a vacuum oven at 60°C for 12 hours to obtain the dried sponge spicules.

[0049] Modification: Add 1 mL of APTES to 99 mL of anhydrous ethanol to prepare a 1% (v / v) APTES-ethanol solution. Add 1 g of dried sponge spicules to 50 mL of this 1% (v / v) APTES-ethanol solution and stir at room temperature for 2 hours. After the reaction, wash repeatedly with anhydrous ethanol and dry in a vacuum oven at 60°C for 2 hours to obtain the modified sponge spicules.

[0050] Preparation of silica sol: Add 100 mL of anhydrous ethanol, 0.15 mL of TEOS, and 0.07 g of PEG 200 to a low-temperature reaction vessel, stir magnetically until completely dissolved, and cool the solution to -20°C to obtain solution A. Add 50 mL of deionized water and 0.08 mL of ammonia water to a flask, stir magnetically to mix evenly, and cool the solution to -20°C to obtain solution B. Keep solution A in a -20°C low-temperature bath, and while stirring magnetically, slowly add solution B to solution A at 0.01 mL / min. After the addition is complete, continue stirring and reacting at -20°C for 36 hours to obtain silica sol.

[0051] Gelation treatment: 0.5 g of the modified sponge spicules was added to the silica sol, mixed, and ultrasonically treated for 10 minutes to obtain a mixed solution. The mixed solution was transferred to a sealed container and allowed to stand at room temperature for 24 hours to obtain a gelled sol.

[0052] Aging: The gelled sol is placed at room temperature for 48 hours for aging, and then dried to obtain a silica sponge-bone spicule mixture.

[0053] It should be noted that the present application prepared a silica sponge spicule mixture. The preparation of this material comprehensively utilizes the natural multi-level pore structure of sponge spicules, silane coupling modification of APTES, and low-temperature sol-gel technology. First, the sponge spicules are activated with hydrochloric acid to remove surface impurities and increase the specific surface area and the number of silanol groups. Subsequently, the sponge spicules are surface-modified by APTES, and amino groups are introduced as anchoring points for subsequent silica binding. The silica sol is prepared by a low-temperature sol-gel method, using TEOS as the silicon source, ammonia catalysis, and PEG 200 as a stabilizer. By controlling the hydrolysis and condensation rates, silica sol particles with uniform size and good dispersibility are obtained. The modified sponge spicules are added to the silica sol, ultrasonically dispersed, and then allowed to stand for gelation, so that the silica sol forms a three-dimensional network structure on the surface and in the pores of the sponge spicules. APTES not only provides amino anchoring points, but may also form a stronger interfacial bond with the silica sol through hydrogen bonds or even dehydration condensation. The gelled sample was then aged to further enhance the gel network strength, and finally dried to obtain the final mixture.

[0054] This application uses method 1 to prepare silica microspheres; utilizes the naturally porous structure of sponge spicules as a template and carrier; and uses APTES to create a chemical bridge between the sponge spicules and silica. The synergistic effect of these three methods results in a composite material (i.e., a silica-sponge-spicule mixture) with a unique hierarchical pore structure (the original pore structure of the sponge spicules combined with the pore structure of the nanosilica gel), a high specific surface area, and excellent interfacial bonding (due to the bridging effect of APTES).

[0055] Next, the prepared silica sponge-bone spicule composite material or monodisperse silica microspheres are used as raw materials to further prepare a composite material.

[0056] Example 3 The preparation method of the silicon dioxide composite material comprises the following specific steps: Dissolve 1 g of chitosan in 100 mL of 2% (v / v) acetic acid solution and stir until completely dissolved to obtain a 1% (w / v) chitosan solution.

[0057] 1 g of the silica sponge-bone spicule mixture prepared in Example 2 was added to 50 mL of a 1% chitosan solution and ultrasonically dispersed for 30 minutes. 10 mL of a 1% (w / v) PEI aqueous solution was added and stirred for 1 hour. 5 mL of a 5% (v / v) glutaraldehyde solution was slowly added dropwise to the mixture and stirred for 2 hours. The resulting gel product was washed and freeze-dried to obtain a silica composite material.

[0058] It should be noted that in this example, chitosan, PEI (polyethyleneimine) and glutaraldehyde were used to construct a cross-linked biopolymer network, in which the silica sponge-bone spicule mixture prepared in Example 2 was encapsulated.

[0059] Chitosan is dissolved in acetic acid to form a positively charged polymer solution, which serves as the matrix of the composite material, leveraging its biocompatibility and film-forming properties. PEI, a positively charged polymer, binds to chitosan through electrostatic interactions, enhancing the material's crosslinking and mechanical properties.

[0060] An inorganic material (a silica-sponge-bone spicule mixture) was combined with an organic biopolymer (chitosan / PEI) to form an organic-inorganic hybrid composite. Leveraging the biocompatibility of chitosan, the positively charged functionalization of PEI, and the cross-linking effect of glutaraldehyde, a three-dimensional network structure was constructed that combines biocompatibility, mechanical properties, and functionalization.

[0061] Example 4 Different from Example 3, the silica sponge-bone spicule mixture prepared in Example 2 was replaced with the monodisperse silica microspheres prepared in Example 1.

[0062] The rest is the same as Example 3.

[0063] It should be noted that, unlike Example 3, in this example, a different composite material was constructed, in which an inorganic material (monodisperse silica microspheres prepared in Example 1) was combined with an organic biopolymer (chitosan / PEI) to form an organic-inorganic hybrid composite material.

[0064] Comparative Example 1 Different from Example 3, the silica sponge-bone spicule mixture prepared in Example 2 was replaced with existing monodisperse silica (manufacturer: Sigma-Aldrich; model: 938254).

[0065] The rest is the same as Example 3.

[0066] Comparative Example 2 Monodisperse silica (manufacturer: Sigma-Aldrich; model: 938254) from the existing technology was directly used as the adsorbent.

[0067] Detection, adsorption test: Prepare tetracycline solution: weigh 0.1 g of tetracycline, dissolve it in 1 L of deionized water, stir well, and adjust the pH to 7.0 to obtain a 100 mg / L tetracycline solution.

[0068] The absorbance of the initial solution was measured using a UV-Vis spectrophotometer: Take 1 mL of tetracycline solution (100 mg / L) and measure the absorbance at a wavelength of 357 nm. The initial absorbance of tetracycline is recorded as A0.

[0069] The adsorption performance of tetracycline by different materials was determined below.

[0070] 0.1 g of the materials prepared in Examples 1 to 4, Comparative Example 1 and Comparative Example 2 were respectively weighed and placed in 50 mL centrifuge tubes.

[0071] Add 50 mL of 100 mg / L tetracycline solution to each centrifuge tube and place the centrifuge tube in a constant temperature shaker at 150 rpm and 25°C.

[0072] Samples were taken out at different time points (0h, 0.5h, 1h, 2h, 4h, 8h, and 24h). Immediately after taking out, the samples were centrifuged at 10,000 rpm for 5 min. 1 mL of the supernatant was taken out with a pipette and added to a UV-Vis cuvette. The absorbance of tetracycline was measured at a wavelength of 350 nm and recorded as A. t (Absorbance at time t).

[0073] According to the Beer-Lambert law, calculate the tetracycline concentration C at time t t (mg / L): C t =C0×(A t / A0) Among them, C0 is the initial concentration (100 mg / L), A0 is the initial absorbance, A t is the absorbance at time t.

[0074] Calculate the adsorption amount / adsorption capacity q at each time point t (mg / g): q t =[(C0-C t )×V] / m Where V is the volume of the solution (0.05 L) and m is the mass of the added material (sample) (0.1 g).

[0075] q t The results are shown in Table 1 below: Table 1

[0076] analyze: According to the test results, the adsorption amount of Example 3 is the highest, and the adsorption amount of Comparative Example 2 is the lowest.

[0077] Example 3: The natural pores of the sponge spicules form hierarchical channels with silica, significantly increasing the specific surface area and exposing more adsorption sites. The amino groups introduced by APTES modification form multiple adsorption sites with the hydroxyl and amino groups of chitosan / PEI, capturing tetracycline through hydrogen bonding and electrostatic interactions. The chitosan-PEI-glutaraldehyde three-dimensional network immobilizes the silica-sponge spicule mixture, further forming a stable porous structure that prevents nanoparticle aggregation and maintains accessibility of active sites.

[0078] Comparative Example 2: Existing silica surfaces are inert, relying on physical adsorption and a small amount of silanol groups, resulting in a low density of adsorption sites. Without a support carrier, particles tend to agglomerate, resulting in a low specific surface area, significantly reducing the effective adsorption area.

[0079] The higher adsorption capacity in Example 1 than in Comparative Example 2 demonstrates that the monodisperse silica microspheres prepared at low temperatures using the present method exhibit superior tetracycline adsorption performance compared to commercially available silica, even in the absence of a carrier material. This is likely due to the increased specific surface area and number of active sites in the silica prepared using the present method.

[0080] The adsorption amount of Example 1 is higher than that of Comparative Example 1, indicating that the silica microspheres prepared at low temperature by the method of the present application have better adsorption performance than the existing silica microspheres, which may be due to the higher specific surface area and activity of the silica microspheres prepared at low temperature.

[0081] The adsorption amount of Example 4 is higher than that of Comparative Example 1, indicating that even without the multi-level porous structure of the sponge-bone needle composite, the monodisperse silica microspheres prepared at low temperature by the method of the present application still have better adsorption performance than the existing silica microspheres after being composited with chitosan / PEI.

[0082] The monodisperse silica microspheres, silica sponge-bone needle mixtures, and silica composite materials prepared in this application have potential application prospects in the fields of adsorption, catalysis, biomedicine, etc., especially in specific fields such as drug purification and chromatographic separation.

[0083] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a silicon dioxide composite material, characterized in that: The steps include: Adding silica microspheres or a silica mixture to a chitosan solution, adding a PEI aqueous solution, stirring to react, adding a glutaraldehyde solution, stirring to react to obtain a gel product, and drying to obtain a silica composite material; The silica mixture includes a silica-sponge-bone spicule mixture, which is prepared by adding sponge spicules into silica sol.

2. The method for preparing a silicon dioxide composite material according to claim 1, wherein The preparation method of silica microspheres comprises the following steps: Anhydrous ethanol, TEOS, and PEG are mixed and cooled to obtain solution A; an ammonia solution is cooled to obtain solution B; solution B is added dropwise to solution A while stirring, and the mixture is stirred for reaction; after the reaction, the mixture is centrifuged twice and dried to obtain silica microspheres.

3. The method for preparing a silicon dioxide composite material according to claim 1, wherein The preparation method of the silica sponge spicule mixture comprises the following steps: adding the sponge spicules into an acid solution, stirring, and drying to obtain dried sponge spicules; Adding APTES to anhydrous ethanol to obtain an APTES ethanol solution; The dried sponge spicules were added into an APTES ethanol solution, stirred, and dried to obtain modified sponge spicules; Anhydrous ethanol, TEOS, and PEG are mixed and cooled to obtain solution A; an ammonia solution is cooled to obtain solution B; solution B is added dropwise to solution A while stirring, and the mixture is stirred to react; after the reaction, silica sol is obtained; The modified sponge spicules are added to the silica sol, mixed, and allowed to stand to obtain a gelled sol; the gelled sol is further allowed to stand for aging, and dried after aging to obtain a silica sponge spicule mixture.

4. The method for preparing a silicon dioxide composite material according to claim 2 or 3, wherein: The cooling temperature is -30~0℃.

5. The method for preparing a silicon dioxide composite material according to claim 2 or 3, characterized in that: When solution B is added dropwise to solution A while stirring, the dropping speed is 0.01-0.2 mL / min.

6. The method for preparing a silicon dioxide composite material according to claim 2, wherein: The method of centrifuging twice after the reaction comprises the following steps: The reaction solution was transferred to a centrifuge tube, centrifuged at 10000-15000 rpm, the supernatant was discarded, a small amount of pre-cooled anhydrous ethanol was added, ultrasonic dispersion was performed, and the solution was centrifuged again at 10000-15000 rpm for washing.

7. The method for preparing a silicon dioxide composite material according to claim 3, wherein: The concentration of APTES in the APTES ethanol solution is 0.5-2%.

8. The method for preparing a silicon dioxide composite material according to claim 2 or 3, characterized in that: The solid-liquid ratio of PEG, anhydrous ethanol and TEOS is 0.05-0.10g:90-110mL:0.12-0.18mL.

9. The method for preparing a silicon dioxide composite material according to claim 1, wherein: The concentration of chitosan in the chitosan solution is 0.5-2%.

10. The method for preparing a silicon dioxide composite material according to claim 1, wherein: The concentration of PEI in the PEI aqueous solution is 0.5-2%.

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