Gadolinium phosphate modified silicon dioxide aerogel and preparation method thereof

Abstract

The invention discloses gadolinium phosphate modified silicon dioxide aerogel and a preparation method thereof. The preparation method comprises the following steps: preparing silicon dioxide sol, introducing gadolinium phosphate, carrying out gelation treatment, carrying out aging treatment, carrying out solvent replacement treatment, carrying out surface modification treatment and carrying out drying treatment. According to the silicon dioxide aerogel prepared by the method disclosed by the invention, the thermal weight loss performance of the silicon dioxide aerogel can be effectively improved by introducing gadolinium phosphate, so that the stability of the silicon dioxide aerogel at a lower temperature is enhanced, the residual mass of the silicon dioxide aerogel at a high temperature is increased, and the heat resistance of the material is greatly improved; therefore, the prepared enhanced silicon dioxide aerogel has wide application prospects in the fields of aerospace, energy storage and conversion, environmental protection and the like, and can bring technical breakthrough and economic benefit improvement to related industries.

Description

Technical Field

[0001] The invention relates to the technical field of aerogel materials, and in particular to a gadolinium phosphate-modified silica aerogel and a preparation method thereof. Background Art

[0002] Aerogel is a new type of material with a nanoporous structure. It has excellent properties such as extremely low density, high specific surface area, and low thermal conductivity. It has broad application prospects in the fields of thermal insulation, adsorption, and catalysis. Silica aerogel is a solid material with a three-dimensional nanoporous structure composed of nanoparticles. It has the characteristics of chemical inertness, thermal insulation, sound insulation, noise reduction, shock absorption, and selective adsorption. It has been widely used in many fields such as industrial thermal insulation and energy saving, power battery safety and fire protection, automobile energy saving and sound insulation, building energy saving, spacecraft thermal insulation, refrigerator cold preservation, etc., and has broad application potential. Silica aerogel is one of the most widely studied aerogels, but its low mechanical strength and high temperature resistance need to be improved, which limits its further application.

[0003] In recent years, in order to improve the performance of silica aerogel, researchers have tried to introduce various reinforcing materials. For example, there is a patent document with application publication number CN113831103A, which discloses a method for preparing a high-temperature resistant alumina-silica aerogel composite material, which is a method for improving the mechanical strength of silica aerogel by doping with alumina; the patent document with application publication number CN114853470A discloses a method for preparing a high-temperature resistant alumina-silica aerogel composite material, and proposes a solution of introducing zirconium oxide to enhance the high-temperature resistance of silica aerogel. These doping methods have improved the performance of silica aerogel to a certain extent, but there are still some shortcomings.

[0004] In recent years, rare earth elements and their compounds have attracted widespread attention in the field of materials. Rare earth elements have unique electronic structures and physical and chemical properties, which can give materials excellent properties. Gadolinium phosphate, as a rare earth compound, has good thermal stability, optical properties and magnetic properties. Studies have shown that introducing gadolinium phosphate into materials can improve the performance of materials. For example, some patents record the application of gadolinium phosphate in the fields of fluorescent materials, catalysts, etc., and have achieved good results.

[0005] After searching, there is no patent report on introducing gadolinium phosphate into silica aerogel to enhance its performance. Therefore, a product and a preparation method for introducing gadolinium phosphate to enhance the performance of silica aerogel are proposed, aiming to solve the problems existing in the existing silica aerogel. Introducing gadolinium phosphate into silica aerogel is expected to combine the advantages of the two and significantly improve the performance of aerogel, thereby expanding its application in more fields, which has important practical significance. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for introducing gadolinium phosphate to enhance the performance of silica aerogel, thereby obtaining a gadolinium phosphate-modified silica aerogel product, so as to solve the problems of low mechanical strength and poor thermal stability of existing silica aerogels, thereby expanding its application in more fields. Specifically, it is a gadolinium phosphate-modified silica aerogel and a preparation method thereof.

[0007] In order to solve the above technical problems, the present invention provides a method for preparing a gadolinium phosphate-modified silica aerogel, the preparation method comprising the following steps:

[0008] S1. Preparation of silica sol: Mix the raw materials silane, water, ethanol and catalyst, stir evenly to obtain silica sol;

[0009] S2. Introduction of gadolinium phosphate: Adding a gadolinium phosphate solution to the silica sol obtained in step S1, stirring uniformly to obtain a sol mixture;

[0010] S3 gelation treatment: The sol mixture obtained in step S2 is placed in a closed container and allowed to stand to gel to form a wet gel;

[0011] S4 aging treatment: The wet gel obtained in step S3 is immersed in a container containing ethanol, and the aged wet gel is obtained by aging treatment;

[0012] S5. Solvent replacement treatment: Solvent replacement treatment of the aged wet gel in step S4 using an organic solvent;

[0013] S6. Surface modification: using a surface modifier to modify the gel after solvent replacement in step S5, and obtaining a preliminary gel product after modification;

[0014] S7. Drying treatment: Drying the gel product obtained in step S6 to obtain gadolinium phosphate-modified silica aerogel.

[0015] Furthermore, using the preparation method described in the present invention, the silane in step S1 is one of tetraethyl orthosilicate and water glass, wherein the molar ratio of the silane, water, ethanol and catalyst is 1:(2-6):(5-15):(0.01-0.1).

[0016] Furthermore, using the preparation method of the present invention, the concentration of the gadolinium phosphate solution in step S2 is 0.1-1.0 mol / L, and the amount thereof added is 1-10% of the mass of the silica sol.

[0017] Furthermore, in the preparation method of the present invention, the gelation treatment in step S3 is performed by standing at a temperature of 20-60° C. and a humidity of 50-70% for 12-48 hours.

[0018] Furthermore, in the preparation method of the present invention, the aging treatment in step S4 is carried out at a temperature of 50-70° C. for 2-4 days, and the ethanol needs to be replaced 2-3 times during the aging period.

[0019] Furthermore, using the preparation method described in the present invention, the organic solvent in step S5 is one or two of ethanol, acetone or n-hexane; the surface modifier in step S6 is one of trimethylchlorosilane, hexamethyldisilazane or methyltrimethoxysilane, and the modification treatment is carried out at a temperature of 50-60°C, and the modification time is 10-24 hours.

[0020] Furthermore, in the preparation method of the present invention, the drying treatment in step S7 is supercritical drying, and the conditions of the supercritical drying are: carbon dioxide as the drying medium, the temperature is 50-60° C., the pressure is 10-14 MPa, and the drying time is 5-8 hours.

[0021] Furthermore, in the preparation method of the present invention, the drying treatment in step S7 is freeze-drying, and the freeze-drying conditions are: temperature of -40 to -80°C, vacuum degree of 10-50Pa, and drying time of 20-30 hours.

[0022] Furthermore, in the preparation method of the present invention, the drying treatment in step S7 is vacuum drying, and the conditions of the vacuum drying are: temperature of 50-70°C, vacuum degree of -0.1 to -0.5Mpa, and drying time of 20-30 hours.

[0023] The invention also provides a gadolinium phosphate-modified silica aerogel, which is prepared by the above preparation method.

[0024] Compared with the prior art, the gadolinium phosphate-modified silica aerogel and its preparation method described in the present invention have the following beneficial effects: a gadolinium phosphate solution is introduced into the silica sol, and a gel is formed through gelation. The synergistic effect of gadolinium phosphate and silica aerogel is utilized to not only enhance the mechanical strength of the aerogel, making it more durable and reliable, but also significantly improve its pore structure, increase the specific surface area, and thus improve the adsorption and thermal insulation properties. At the same time, by precisely controlling the introduction ratio of gadolinium phosphate and the process conditions, the thermal stability of the silica aerogel is significantly improved, so that it can maintain excellent performance in a wider range of high-temperature environments, greatly expanding its scope of application. In addition, the entire preparation method is relatively simple, easy to operate and control, and has a reasonable cost, which is conducive to large-scale industrial production.

[0025] It can be seen that the silica aerogel prepared by the method of the present invention can effectively improve the thermal weight loss performance of the silica aerogel by introducing gadolinium phosphate, so that its stability at lower temperatures is enhanced, and the residual mass at high temperatures is increased, which greatly improves the heat resistance of the material. Therefore, the prepared enhanced silica aerogel has broad application prospects in many fields such as aerospace, energy storage and conversion, and environmental protection, and can bring technological breakthroughs and improved economic benefits to related industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0027] Figure 1 It is a thermogravimetric curve diagram of the aerogel prepared by the method of the present invention and the existing aerogel. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example 1

[0030] A method for preparing a gadolinium phosphate-modified silica aerogel, the preparation method comprising the following steps:

[0031] S1. Preparation of silica sol: 20 mL of ethyl orthosilicate, 40 mL of ethanol and 20 mL of deionized water were mixed in a volume ratio of 1:2:1, 5 mL of ammonia (25%) was added dropwise under stirring, the pH value was adjusted to 9, and the reaction was stirred for 3 hours to obtain a silica sol;

[0032] S2. Introduction of gadolinium phosphate: 2 g of gadolinium phosphate was dissolved in 10 mL of deionized water to obtain a gadolinium phosphate solution, and the prepared gadolinium phosphate solution was then added dropwise to the silica sol and stirred to obtain a sol mixture;

[0033] S3. Gelation treatment: The sol mixture was placed in a sealed container at a temperature of 40 ° C and a humidity of 60% for 18 hours, and the mixture was allowed to stand to form a wet gel;

[0034] S4. Aging treatment: The wet gel was immersed in a container containing ethanol for aging treatment at an aging temperature of 55°C for 3 days, during which the ethanol was replaced twice to obtain an aged wet gel;

[0035] S5. Solvent replacement treatment: The aged wet gel was solvent replaced with ethanol and n-hexane in turn, each replacement time was 18 hours;

[0036] S6. Surface modification: The wet gel after solvent replacement was immersed in an ethanol solution containing hexamethyldisilazane (HMDS) surface modifier (HMDS volume fraction was 15%) for surface modification at a temperature of 55° C. for 12 hours to obtain a gel product after modification;

[0037] S7. Drying treatment: Using supercritical drying technology, the surface-modified wet gel is placed in a supercritical drying device, and carbon dioxide is used as the drying medium. It is dried for 6 hours at a temperature of 55°C and a pressure of 14MPa. After drying, gadolinium phosphate-modified silica aerogel is obtained.

[0038] Example 2

[0039] A method for preparing a gadolinium phosphate-modified silica aerogel, the preparation method comprising the following steps:

[0040] S1. Preparation of silica sol: 30 mL of ethyl orthosilicate, 75 mL of ethanol and 36 mL of deionized water were mixed in a volume ratio of 1:2.5:1.2, 7 mL of ammonia (25%) was added dropwise under stirring, the pH value was adjusted to 9.5, and the reaction was stirred for 3.5 hours to obtain a silica sol;

[0041] S2. Introduction of gadolinium phosphate: 3 g of gadolinium phosphate was dissolved in 15 mL of deionized water to obtain a gadolinium phosphate solution, and the prepared gadolinium phosphate solution was added dropwise to the silica sol and stirred to obtain a sol mixture;

[0042] S3. Gelation treatment: The sol mixture was placed in a sealed container at a temperature of 45 ° C and a humidity of 70% for 20 hours, and the mixture was allowed to stand to form a wet gel;

[0043] S4. Aging treatment: The wet gel was immersed in a container containing ethanol for aging treatment at an aging temperature of 50°C for 4 days, during which the ethanol was replaced 3 times to obtain an aged wet gel;

[0044] S5. Solvent replacement treatment: The aged wet gel was solvent replaced with ethanol and acetone in turn, each replacement time was 20 hours;

[0045] S6. Surface modification: The wet gel after solvent replacement was immersed in an ethanol solution containing trimethylchlorosilane (TMCS) surface modifier (the volume fraction of TMCS was 10%) for surface modification at a temperature of 55° C. for 12 hours to obtain a primary gel after modification;

[0046] S7. Drying treatment: Using freeze-drying technology, the surface-modified wet gel is placed in a freeze-drying device and dried at a temperature of -55°C and a vacuum degree of 12 Pa for 25 hours to obtain gadolinium phosphate-modified silica aerogel.

[0047] Example 3

[0048] A method for preparing a gadolinium phosphate-modified silica aerogel, the preparation method comprising the following steps:

[0049] S1. Preparation of silica sol: 50 g of water glass was diluted with 150 g of deionized water to a concentration of 10 wt %, stirred evenly, and then 150 mL of ethanol was added to mix, and 20 mL of (25%) ammonia was added dropwise under stirring, and the pH value was adjusted to 8.5, and the reaction was stirred for 2 hours to obtain a silica sol;

[0050] S2. Introduction of gadolinium phosphate: 3 g of gadolinium phosphate was dissolved in 50 mL of deionized water to prepare a gadolinium phosphate solution having a concentration of 5 wt %, and then the prepared gadolinium phosphate solution was added to the silica sol and stirred to obtain a sol mixture;

[0051] S3. Gelation treatment: The sol mixture was placed in a sealed container at a temperature of 60 ° C and a humidity of 60% for 20 hours, and the mixture was allowed to stand to form a wet gel;

[0052] S4. Aging treatment: The wet gel was immersed in a container containing ethanol for aging treatment at an aging temperature of 70°C for 2 days, during which the ethanol was replaced twice to obtain an aged wet gel;

[0053] S5. Solvent replacement treatment: The aged wet gel was solvent replaced with ethanol and n-hexane in turn, each replacement time was 24 hours;

[0054] S6. Surface modification: The wet gel after solvent replacement was immersed in an ethanol solution containing hexamethyldisilazane (HMDS) surface modifier (HMDS volume fraction was 10%) for surface modification at a temperature of 55° C. for 12 hours to obtain a gel product after modification;

[0055] S7. Drying treatment: Using vacuum drying technology, the surface-modified wet gel is placed in a vacuum drying oven and dried for 24 hours at a temperature of 60°C and a vacuum degree of -0.1Mpa to obtain gadolinium phosphate-modified silica aerogel.

[0056] Comparative Example

[0057] A method for preparing a silica aerogel, the method comprising the following steps:

[0058] S1. Measure a certain amount of ethyl orthosilicate, ethanol and deionized water, mix them in a container in a molar ratio of 1:4:8, and stir them evenly to obtain solution A.

[0059] S2. Add concentrated hydrochloric acid dropwise to solution A to adjust the pH value of the solution to 2-3, and continue stirring at 55° C. for 1 hour to fully hydrolyze the ethyl orthosilicate to obtain solution B.

[0060] S3. Slowly add concentrated ammonia water to solution B to adjust the pH value of the solution to 8-9 to promote the formation of gel, and stir for 3 hours to form a wet gel.

[0061] S4. Place the wet gel in a sealed container and age at 50°C for 24 hours.

[0062] S5. The aged gel was subjected to solvent replacement by first soaking in ethanol for 3 times, each time for 6 hours.

[0063] S6. The replaced gel is subjected to supercritical drying, using carbon dioxide as the medium, and dried at a temperature of 50° C. and a pressure of 1 MPa for 8 hours to obtain a traditional silica aerogel.

[0064] The performance tests were conducted on the gadolinium phosphate modified silica aerogels prepared in Examples 1 to 3 and the conventional silica aerogels prepared in the comparative example. The results are shown in the following table:

[0065]

[0066] From the above test performance comparison data, it can be seen that after the introduction of gadolinium phosphate, the aerogel has significantly improved in mechanical properties, thermal stability and porosity, which fully proves the effectiveness of introducing gadolinium phosphate to enhance the performance of silica aerogel and provides better performance guarantee for it in practical applications.

[0067] The method for preparing a gadolinium phosphate-modified silica aerogel provided by the present invention has a reaction mechanism including four stages, namely, a hydrolysis stage, a polymerization stage, a condensation stage and a cross-linking stage. The reaction mechanism of each stage is as follows:

[0068] S1. Hydrolysis stage:

[0069] Tetraethyl orthosilicate silicic acid:

[0070] Si(OC2H5)4+4H2O→Si(OH)4+4C2H5OH (1)

[0071] Gadolinium phosphate hydrolysis:

[0072]

[0073] S2. Aggregation stage:

[0074] Silicic acid polymerization:

[0075] 2Si(OH)4→(OH)3Si-O-Si(OH)3+H2O (3)

[0076] The role of phosphate and silicate hydroxyl groups:

[0077]

[0078] S3. Polycondensation stage:

[0079] Condensation between silicic acid:

[0080] (OH)3Si-O-Si(OH)3+(OH)3Si-O-Si(OH)3→(OH)3Si-O-Si(OH)2-O-Si(OH)3+H2O(5)

[0081] Condensation of phosphorus-containing species with silicic acid:

[0082] Si(OH)3-O-PO3H2+(OH)3Si-O-Si(OH)3→(OH)3Si-O-Si(OH)2-O-PO3H2+H2O (6)

[0083] S4. Cross-linking stage:

[0084] Three-dimensional network cross-linked structure:

[0085] (OH)3Si-O-Si(OH)2-O-PO3H2+(OH)3Si-O-Si(OH)2-O-Si(OH)3+Gd(OH)2PO4→(OH)3Si-O-Si(OH)2-O-Si(OH)3-O-Gd-O-PO4-O-Si(OH)2-O-Si(OH)3+H2O (7)

[0086] The gadolinium phosphate modified silica aerogel obtained by the preparation method provided by the present invention is subjected to thermogravimetric analysis with conventional pure silica aerogel. The thermogravimetric analysis curves of conventional pure SiO2 aerogel and gadolinium phosphate modified SiO2 aerogel are as follows: Figure 1 As shown, from Figure 1 From the curve in the graph, we can see that the initial weight loss temperature of the aerogel modified with gadolinium phosphate is relatively low, at 250°C, and there is a partial mass loss of about 9% at around 300°C; while the conventional silica aerogel is 300°C, and there is a partial mass loss of about 8% at around 320°C. This shows that the silica aerogel modified with gadolinium phosphate begins to lose weight at a relatively low temperature. At a high temperature of 800°C, the residual mass of the silica aerogel modified with gadolinium phosphate is 45%, which is higher than the 32% of the conventional silica aerogel. This shows that after the introduction of gadolinium phosphate, the stability of the aerogel at high temperatures has been greatly improved.

[0087] It can be seen that the gadolinium phosphate-modified silica aerogel prepared by introducing gadolinium phosphate can effectively improve the thermal weight loss properties of silica aerogel, enhance its stability at lower temperatures, and at the same time, increase the residual mass at high temperatures, thereby improving the heat resistance of the material.

[0088] The gadolinium phosphate-modified silica aerogel obtained by the preparation method provided by the present invention can enhance the performance of the silica aerogel by introducing gadolinium phosphate, and effectively solve the problems of low mechanical strength and poor thermal stability of the existing silica aerogel. Specifically, it aims to achieve the following important goals:

[0089] First, the mechanical strength of silica aerogel is significantly improved. Traditional silica aerogel is fragile and brittle, which limits its wide application in many fields. By introducing gadolinium phosphate, a unique microstructure and chemical bonding are formed, and the skeleton structure of aerogel is strengthened, thereby greatly improving its mechanical properties such as compression and tensile strength, enabling it to withstand more complex use environments and mechanical conditions.

[0090] The second is to optimize thermal stability. Silica aerogels often have insufficient thermal stability in high temperature environments. The introduction of gadolinium phosphate in the present invention can improve the thermal conductivity and heat capacity characteristics of aerogels, significantly improve their structural stability and thermal insulation performance under high temperature conditions, and broaden their application range in the field of high temperature thermal insulation.

[0091] Third, chemical stability is enhanced. Existing silica aerogels are prone to chemical reactions in certain chemical environments, resulting in performance degradation. The preparation method of the present invention allows gadolinium phosphate to be evenly distributed in the network structure of the aerogel, effectively blocking the erosion and penetration of chemical substances, improving the aerogel's tolerance to chemical substances such as acids and alkalis, and extending its service life.

[0092] Fourth, the hydrophobicity is improved. Many application scenarios require silica aerogel to have good hydrophobic properties. Through the process of the present invention, the introduction of gadolinium phosphate can adjust the chemical composition and micro-roughness of the aerogel surface, significantly enhancing its hydrophobicity, so that it can still maintain excellent insulation, adsorption and other properties in a humid environment.

[0093] Fifth, simplify the preparation process and reduce costs. While ensuring the improvement of the performance of silica aerogel, optimize and innovate the preparation process, reduce complex operating steps and the use of expensive raw materials, and achieve an efficient, economical, and large-scale production method to promote its widespread application and promotion in the industrial field.

[0094] In summary, the silica aerogel obtained by the preparation method of the present invention, by introducing gadolinium phosphate, comprehensively improves the mechanical strength, thermal stability, chemical stability, and hydrophobicity of the silica aerogel, simplifies the preparation process, and reduces the production cost, providing a better quality and more reliable material solution for the application of silica aerogel in many fields such as insulation, catalysis, and adsorption.

[0095] Other aspects of the present invention that are not described in detail are all conventional techniques known to those skilled in the art.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a gadolinium phosphate-modified silica aerogel, characterized in that: The preparation method comprises the following steps: S1. Preparation of silica sol: Mix the raw materials silane, water, ethanol and catalyst, stir evenly to obtain silica sol; S2. Introduction of gadolinium phosphate: Adding a gadolinium phosphate solution to the silica sol obtained in step S1, stirring uniformly to obtain a sol mixture; S3 gelation treatment: The sol mixture obtained in step S2 is placed in a closed container and allowed to stand to gel to form a wet gel; S4 aging treatment: The wet gel obtained in step S3 is immersed in a container containing ethanol, and the aged wet gel is obtained by aging treatment; S5. Solvent replacement treatment: Solvent replacement treatment of the aged wet gel in step S4 using an organic solvent; S6. Surface modification: using a surface modifier to modify the gel after solvent replacement in step S5, and obtaining a preliminary gel product after modification; S7. Drying treatment: Drying the gel product obtained in step S6 to obtain gadolinium phosphate-modified silica aerogel.

2. The method for preparing the gadolinium phosphate modified silica aerogel according to claim 1, characterized in that: The silane in step S1 is one of ethyl orthosilicate and water glass, wherein the molar ratio of the silane, water, ethanol and catalyst is 1:(2-6):(5-15):(0.01-0.1).

3. The method for preparing the gadolinium phosphate modified silica aerogel according to claim 1, characterized in that: The concentration of the gadolinium phosphate solution in step S2 is 0.1-1.0 mol / L, and the amount added is 1-10% of the mass of the silica sol.

4. The method for preparing the gadolinium phosphate modified silica aerogel according to claim 1, characterized in that: The gelation treatment in step S3 is performed by standing still under the conditions of a temperature of 20-60° C. and a humidity of 50-70% for a standing time of 12-48 hours.

5. The method for preparing the gadolinium phosphate modified silica aerogel according to claim 1, characterized in that: The aging treatment in step S4 is carried out at a temperature of 50-70° C. for 2-4 days, during which ethanol needs to be replaced 2-3 times.

6. The method for preparing the gadolinium phosphate modified silica aerogel according to claim 1, characterized in that: The organic solvent in step S5 is one or two of ethanol, acetone or n-hexane; the surface modifier in step S6 is one of trimethylchlorosilane, hexamethyldisilazane or methyltrimethoxysilane, and the modification treatment is carried out at a temperature of 50-60° C. and the modification time is 10-24 hours.

7. The method for preparing the gadolinium phosphate modified silica aerogel according to claim 1, characterized in that: The drying process in step S7 is supercritical drying, and the conditions of the supercritical drying are: using carbon dioxide as the drying medium, the temperature is 50-60° C., the pressure is 10-14 MPa, and the drying time is 5-8 hours.

8. The method for preparing the gadolinium phosphate modified silica aerogel according to claim 1, characterized in that: The drying process in step S7 is freeze drying, and the freeze drying conditions are: temperature of -40 to -80°C, vacuum degree of 10-50Pa, and drying time of 20-30 hours.

9. The method for preparing the gadolinium phosphate modified silica aerogel according to claim 1, characterized in that: The drying process in step S7 is vacuum drying, and the conditions of the vacuum drying are: temperature of 50-70° C., vacuum degree of -0.1 to -0.5 MPa, and drying time of 20-30 hours.

10. A gadolinium phosphate modified silica aerogel, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 9.

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