CN115703638A

CN115703638A - Ultrahigh-purity uniform spherical nano silicon oxide particles and preparation method thereof

Info

Publication number: CN115703638A
Application number: CN202110936849.XA
Authority: CN
Inventors: 王树东; 杨勍; 苏宏久; 张珂; 任高远; 高云峰
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2021-08-16
Filing date: 2021-08-16
Publication date: 2023-02-17

Abstract

The application discloses ultra-high-purity uniform spherical nano silicon oxide particles and a preparation method thereof, wherein the method comprises the steps of adding an aqueous phase solution into a raw material containing an organic silicon source, and heating for reaction to obtain the nano silicon oxide particles; the aqueous phase solution is selected from one of water and an aqueous solution containing a pH regulator. Compared with the conventional

The application provides a method for preparing spherical nano silicon oxide by a reverse addition process by utilizing the phase dissolution principle of an organic silicon source and a water phase system. The nano particles prepared by the preparation method have narrow distribution, high uniformity and PDI<0.1, high sphericity. In addition, the nano-scale prepared by the methodThe mass fraction of silicon oxide is higher than that of the conventional silicon oxide

Description

Ultrahigh-purity uniform spherical nano silicon oxide particles and preparation method thereof

Technical Field

The application relates to ultrahigh-purity uniform spherical nano silicon oxide particles and a preparation method thereof, belonging to the field of material preparation.

Background

Based on the characteristics of no toxicity, five flavors, no pollution and recycling of silicon oxide materials, silicon oxide has been widely applied in the industries of glass, ceramics, monocrystalline silicon and the like. The nano-scale silicon oxide has the excellent characteristics of small particle size, large specific surface area, small size effect, quantum size effect, surface interface effect and the like which are unique to nano materials, and has wide application in the industries of biomedicine, electronics, catalyst carriers, buildings, coatings and the like. Especially, the property controllability of the silicon oxide surface can realize the fusion of the silicon oxide surface with materials such as organic, inorganic, high polymer and the like, and the performance and the application field of the nano silicon oxide particles are greatly expanded.

The preparation method of nano silicon dioxide is divided into a physical method and a chemical method. The physical method is mechanical pulverization method, and SiO is pulverized by using a super-jet mill or a high-energy ball mill ₂ The aggregate is crushed to obtain the particle size range of 50nm-5 mu m, and the particle size is relatively large. Chemical methods, which are the most commonly used methods, include a gas phase chemical method (CVD), a chemical precipitation method, a sol-gel method, a micro-emulsion method, and the like. CN106348306 in 2017 discloses a method for preparing nano silicon oxide by using a gas-phase chemical method with an oxyhydrogen flame method, wherein the temperature of the gasification reaction is 2300-2600 ℃. The chemical precipitation method is mainly that inorganic water glass and acid solution are mixed to adjust pH value to obtain needed silicon oxide particles; microemulsions generally consist of a surfactant, a co-surfactant, an oil (usually a small polar organic), and water. The surfactant surrounds the aqueous phase and is dispersed in the continuous oil phase, and the surrounded water core is an independent 'microreactor'. Has the advantages of good particle dispersibility, narrow particle size distribution, easy regulation and control, and the like. But is prepared by microemulsion methodThis is expensive and therefore not suitable for mass production. In addition, CN101746767 in 2009 discloses a method for preparing high-purity spherical nano-silica by plasma hydro-thermal reduction, wherein the obtained nano-silica has a particle distribution of 50-200 nm and a purity of more than 99.99%; CN109052418 discloses a preparation method of spherical nano-silica in 2018, which mainly takes eucalyptus as a raw material, and the raw material is mixed with sludge at the river bottom to obtain a self-control template through high-temperature and high-humidity treatment, and finally the nano-silica is prepared by adopting a homogeneous precipitation method. CN111252779 discloses in 2020 a preparation method of spherical nano-silica, which mainly performs oxidation reaction on silicon powder therein under the action of electromagnetic waves to obtain spherical nano-silica.

The most used method at present is

The method comprises the following steps:

the method is the main method for preparing the silicon dioxide small spherical particles at present. Earliest quilt

(Stober W, fink A, bohn E.Controledgrowth of monidsperses in micro size range. Journal of Colloid and Interface Science,1968,26 (1): 62-9.) and was further improved for the preparation of silica spheres of various properties. The process takes silicate as a silicon source, absolute ethyl alcohol or methanol as a solvent, ammonia water or other alkali as a catalyst, and hydrolyzes and polycondenses under the condition of water content. Finally, forming silica sol, and preparing the silicon dioxide pellets through certain post-treatment.

SiO prepared by the method ₂ The nano particles have good dispersibility, controllable particle size and good monodispersity.

Albeit classic

The method can realize the preparation of nano particles, but the solid content of the nano silicon oxide prepared by the process is relatively low and is generally below 6 percent; to achieve higher solids preparations, complex systems and longer times are required (Herbert Giesche, synthesis of Monochromatic Silica Powders II. Controlled Growth Reaction and Continuous Production Process, journal of European Ceramic Society,1994, 14.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention discloses a preparation method of ultra-high purity uniform spherical nano silicon oxide particles and a traditional method

The invention provides a method for preparing spherical nano silicon oxide by a reverse addition process by utilizing the principle of dissolving an organic silicon source and a solvent-water phase system. The preparation method can realize controllable preparation of spherical nano silica particles with the size of 30-150 nm, and the prepared nano particles have narrow distribution, high uniformity and PDI<0.1, high sphericity and the like. In addition, the mass fraction of the nano silicon oxide prepared by the invention is higher than that of the nano silicon oxide prepared by the traditional method

The preparation method of the forward processing technology can realize the preparation of a product with high silicon oxide concentration (the silicon oxide concentration of the process can reach 7-15 wt percent, and the data is far higher than that of the traditional product

The concentration of the silicon oxide obtained by the method is less than 6wt.%, and the metal impurity ions of the prepared ultra-high purity nano silicon oxide are less than 1ppm.

According to one aspect of the present application, a method for preparing nano silica particles is provided, which comprises adding an aqueous solution to a raw material containing an organic silicon source, and heating for reaction to obtain the nano silica particles, wherein the aqueous solution is selected from one of water and an aqueous solution containing a pH regulator.

Optionally, the organic silicon source is selected from at least one of formula I;

wherein R is ₁ ，R ₂ ，R ₃ Is independently selected from C _1-4 Alkoxy, hydrophobic, hydrophilic, silicon-containing groups;

R ₄ is selected from C _1-4 At least one of alkyl groups; including methyl, ethyl, propyl, butyl;

C _1-4 alkoxy groups include methoxy, ethoxy, propoxy, butoxy;

the hydrophobic group is selected from C _1-3 Alkyl, phenyl, C _2-3 One of epoxy groups; including methyl, ethyl, propyl, phenyl, C _2-3 An epoxy group;

the hydrophilic group is selected from at least one of aminopropyl, mercaptopropyl and chloropropyl;

the silicon-containing group is selected from one of silicon-based trimethoxy group, silicon-based triethoxy group and silicon-based tripropoxy group.

Optionally, the raw material containing the organic silicon source comprises an organic base I, an organic solvent;

the molar ratio of the organic silicon source to the organic base I to the organic solvent is as follows:

an organic silicon source: an organic base I: organic solvent =1:0 to 5:0 to 5, wherein the mole number of the organic silicon source is calculated by the mole number of silicon oxide;

the organic base I is at least one selected from monoethanolamine, diethanolamine, triethylamine, diethylamine, pyridine, isopropanolamine, tetraethylammonium hydroxide, triethylenediamine and morpholine;

the organic solvent is selected from at least one of methanol, ethanol, propanol, isopropanol, benzene, toluene, ethylbenzene, xylene, aromatic hydrocarbon and cyclohexane.

Optionally, the aqueous phase solution has a pH of 7 to 12.

Optionally, the reaction temperature is 55 to 95 ℃.

Optionally, the ratio of the molar amount of water in the aqueous phase solution to the molar amount of the organic silicon source is 4 to 100; wherein the molar amount of the organic silicon source is calculated by the molar amount of silicon oxide.

Optionally, the adding rate of the aqueous phase solution is 0.2-50 kg/(kg reaction liquid x hr); the mass of the reaction liquid per unit mass is 0.2-50 kg of the water phase added per hour;

wherein the reaction liquid is a mixed liquid of an aqueous phase solution and a raw material containing an organic silicon source;

optionally, the pH regulator is selected from at least one of inorganic base and organic base II;

the inorganic alkali is selected from one or more of ammonia water, sodium hydroxide, potassium hydroxide, magnesium hydroxide and calcium hydroxide;

the organic base II is one or more selected from monoethanolamine, diethanolamine, triethylamine, diethylamine, isopropanolamine, tetraethylammonium hydroxide, triethylenediamine and morpholine;

optionally, aging is also included in the method;

the aging temperature is 55-95 ℃; aging for 0.5-4 hr;

preferably, the aging temperature is 65-95 ℃; the aging time is 0.5-2 hr.

According to yet another aspect of the present application, there is provided nano silica particles prepared by the method.

Optionally, the micro-morphology of the nano silicon oxide particles is spherical, and the particle size of the particles is 30-150 nm; monodisperse, concentration of particles PDI <0.1;

preferably, the particle size of the nano silicon oxide particles can be independently selected from 30nm, 35nm, 40nm, 50nm, 58nm, 60nm, 65nm, 70nm, 80nm, 83nm, 85nm, 90nm and 100nm.

Optionally, the solid content of the nano silicon oxide particles is 7wt.% to 20wt.%,

preferably, the solid content ranges from 7wt.% to 15wt.%.

Optionally, the metal ion content in the nano silica particles is less than 1ppm;

preferably, the metal ion content in the nano silica particles is less than 600ppb.

The beneficial effect that this application can produce includes:

1) The invention discloses a preparation method of ultra-high purity uniform spherical nano silicon oxide particles and a traditional method

The invention discloses a method for preparing spherical nano silicon oxide by adding aqueous phase solution into a silicon source through a reverse addition process by utilizing the principle of phase dissolution of a silane reaction system. The preparation method can realize controllable preparation of spherical nano silica particles with the size of 30-150 nm, and the prepared nano particles have narrow distribution, high uniformity and PDI<0.1, high sphericity, high purity, etc.

2) Because of adopting the reverse addition process, the mass fraction of the nano silicon oxide prepared by the invention is higher than that of the traditional nano silicon oxide

The preparation method of the forward processing technology can realize the preparation of a product with high silicon oxide concentration (the silicon oxide concentration of the process can reach 7-15 wt percent, and the data is far higher than that of the traditional product) by adjusting the control of the reverse addition amount of the aqueous phase solution

The process results in a silica concentration (less than 6 wt.%).

3. The preparation method disclosed by the invention is simple in process operation and easy for industrial amplification.

Drawings

Fig. 1 is a particle size distribution test chart of nano-silica prepared in example 1.

Fig. 2 is a particle size distribution test chart of nano-silica prepared in example 2.

Fig. 3 is a particle size distribution test chart of nano-silica prepared in example 3.

Fig. 4 is a particle size distribution test chart of nano-silica prepared in example 4.

Fig. 5 is a particle size distribution graph of nano-silica prepared in example 5.

Fig. 6 is a particle size distribution test chart of nano-silica prepared in example 6.

Fig. 7 is a particle size distribution detection graph of nano-silica prepared in comparative example 1.

Fig. 8 is a particle size distribution detection diagram of nano-silica prepared in comparative example 2.

Fig. 9 is an SEM characterization of the nanosilica prepared in example 1.

Fig. 10 is an SEM characterization of the nanosilica prepared in example 2.

Fig. 11 is an SEM characterization of the nanosilica prepared in example 3.

Fig. 12 is an SEM characterization of the nanosilica prepared in example 4.

Fig. 13 is an SEM characterization of the nanosilica prepared in example 5.

Fig. 14 is an SEM characterization of the nanosilica prepared in example 6.

Fig. 15 is an SEM characterization of the nanosilica prepared in comparative example 1.

Fig. 16 is an SEM characterization of the nanosilica prepared in comparative example 2.

Detailed Description

The following detailed description of the present invention is provided with reference to the accompanying drawings and examples, which are not intended to limit the present invention. The details and forms of the present invention may be modified by those skilled in the art within the principle of the present invention, and such modifications are within the scope of the present invention.

The particle size data in the embodiment of the invention is the result obtained by adopting nano Malvern laser particle size analysis and electronic scanning electron microscope detection.

Unless otherwise specified, the raw materials in the examples of the present application were all purchased commercially.

Among them, organic silicon source reagents (n-silane methyl ester, n-silane ethyl ester, etc.), alcohol solvents, tetramethylammonium hydroxide, ethanolamine, etc. are all purchased from Chinese medicines.

Wherein:

the method for calculating the solid content is as follows:

solid content = mass m of solid particles obtained by drying/(mass of sample of solution).

Example 1

1. Respectively mixing 22.5g of n-silane methyl ester and 5g of methanol to form uniform solutions, heating to 75 ℃, and stirring for later use to form a solution A;

2. putting 108g of deionized water into a beaker, adding 25% of tetramethylammonium hydroxide solution, adjusting the pH of the solution to 10.5, and stirring uniformly for later use to form a solution B;

3. adding the solution B into the solution A at a rate of 10 g/(kg reaction solution x hr), and keeping the temperature of the reaction solution at 75 ℃;

4. the solution formed in step 3 was aged at 75 ℃ for 1 hour.

The resulting sample was labeled 1 ^# The obtained product was analyzed for particle size using a malvern laser particle sizer (Marlven NanoZS90 as a test instrument), the average particle size was 59.31nm, the concentration PDI value was 0.008, and the results are shown in fig. 1.

Example 2

1. Respectively mixing 22.5g of n-silane methyl ester and 10g of toluene to form uniform solutions, heating to 75 ℃, and stirring for later use to form a solution A;

2. putting 108g of deionized water into a beaker, adding 25% of tetramethylammonium hydroxide solution, and adjusting the pH of the solution to 10.5; stirring uniformly to form a solution B;

3. adding the solution B into the solution A at a rate of 10 g/(kg of reaction solution x hr), and keeping the temperature of the reaction solution at 75 ℃;

4. the solution formed in step 3 was aged at 75 ℃ for 1 hour.

The resulting sample was labeled 2 ^# The obtained product was analyzed for particle size using a malvern laser particle sizer, and the average particle size was 52.56nm, and the concentration PDI value was 0.028, and the results are shown in fig. 2.

Example 3

1. Respectively mixing 22.5g of n-silane methyl ester and 10g of toluene to form a uniform solution, heating to 75 ℃, stirring for later use, and marking as a solution A;

2. putting 56g of deionized water into a beaker, adding 25% of tetramethylammonium hydroxide solution, and adjusting the pH of the solution to 10.5; stirring uniformly to form a solution B;

4. the solution formed in step 3 was aged at 75 ℃ for 1 hour.

The resulting product is marked as number 3 ^# The particle size was analyzed by a Malvern laser particle sizer, and the average particle size was 87.08nm, and the PDI value was 0.005, and the results are shown in FIG. 3.

Example 4

1: respectively mixing 22.5g of n-silane methyl ester and 10g of toluene to form uniform solution, and then heating to 75 ℃ and stirring for later use; the solution A formed;

3. adding the solution B into the solution A at a rate of 5.0 g/(kg of reaction solution x hr), and keeping the temperature of the reaction solution at 75 ℃;

4. the solution formed in step 3 was aged at 75 ℃ for 1 hour.

The resulting sample was labeled 4 ^# The particle size of the obtained product was analyzed by a malvern laser particle sizer, and the average particle size was 83.12nm, and the concentration PDI value was 0.03, and the results are shown in fig. 4.

Example 5

1: respectively mixing 22.5g of n-silane methyl ester and 10g of toluene to form a uniform solution, and then heating to 85 ℃ and stirring for later use; the solution A formed;

3. adding the solution B into the solution A at a rate of 10 g/(kg reaction solution hr), and keeping the temperature of the reaction solution at 85 ℃;

4. the solution formed in step 3 was aged at 85 ℃ for 1 hour.

The resulting sample was labeled 5 ^# The obtained product was analyzed for particle size using a Malvern laser particle sizer, the average particle size was 83.32nm, the concentration PDI value was 0.016, and the results are shown in FIG. 5.

Example 6

1: respectively mixing 22.5g of n-silane methyl ester, 6g of triethylamine and 10g of toluene to form a uniform solution, and then heating to 75 ℃ and stirring for later use; forming a solution A;

2. placing 108g of deionized water into a beaker to form a solution B;

4. the solution formed in step 3 was aged at 75 ℃ for 1 hour.

The resulting sample was labeled 6 ^# The obtained product was analyzed for particle size using a malvern laser particle sizer, and the average particle size was 122.9nm, and the concentration PDI value was 0.028, and the results are shown in fig. 6.

Comparative example 1

The comparative example mainly uses

The process for synthesizing the nano silicon oxide comprises the following specific steps:

1. adding 0.41g of strong ammonia water into 71.6g of deionized water, uniformly stirring, and then adding 23g of ethanol, and stirring to obtain a mixed solution A;

2. mixing 17.9g of ethyl orthosilicate and 23g of ethanol to form a solution B;

3. heating the solution A to 60 ℃, and then adding the solution B into the solution A at the speed of 1 ml/min;

4. then aged, and the resulting nanoparticle was labeled as comparative sample 1 ^# 。

Comparative example 2

The comparison example is mainly based on

1. adding 0.41g of strong ammonia water into 71.6g of deionized water, uniformly stirring, and stirring to obtain a mixed solution A;

2. heating the solution A to 60 ℃, and then adding 17.9g of tetraethoxysilane into the solution A at the speed of 1 ml/min;

4. then aged, and the resulting nanoparticle was labeled as comparative sample 2 ^# 。

Test example 1

For sample 1 respectively ^# ～6 ^# And comparative sample 1 ^# ，2 ^# The morphology test was carried out with a JEOL JSM-7800F Scanning Electron Microscope (SEM).

The test results showed that sample 1 ^# ～6 ^# The particle sizes of the particles are respectively 60nm, 52nm, 85nm, 83nm, 85nm and 125nm.

Test example 2

For sample 2 ^# ，3 ^# Comparative sample 1 ^# ，2 ^# Drying was carried out by using the aqueous silica gel sample 2 of examples 2,3 ^# 、3 ^# Comparative example 1,2 aqueous silica gel sample comparative sample 1 ^# ，2 ^# 20g of the sample was weighed, and then dried at 120 ℃ for 12 hours, and then the mass m of the obtained solid particles was weighed.

The solids contents of the silica obtained in examples 2,3 were 7.2wt.% and 12.4wt.%, respectively, by the drying method described above; the solids contents of the silicas obtained in comparative examples 1,2 were 5.7wt.% and 7.2wt.%, respectively.

Test example 3

And respectively detecting metal ions of the sample aqueous solution silica sol sample by using an ICP-MS (NS 2000) testing instrument.

For sample 3 ^# The detection results of (a) are as follows:

TABLE 1 sample No. 3 Metal ion content

From the above-described example 1 ^# ～6 ^# It can be found that the spherical nano silicon oxide particles can be well prepared by adopting the reverse processing technology.

From 1 ^# And 2 ^# As a result of the sample, it can be seen that toluene which is incompatible with alcohols and water is used as a solvent, and as a result, although the compatibility between the two solvents and water is large, the size difference of the particles synthesized by the two methods is not large, and is 59.31nm and 52.56nm respectively, and the concentration ratio of the particles is relatively high.

Sample 2 ^# And 3 ^# The solvent water in example 3 was added in half the amount of example 2, and as a result, it was found that 3 ^# Particle diameter ratio of sample 2 ^# The sample size and diameter were 87.08nm (3) ^# Sample) and 52.56nm (2) ^# Sample), and the distribution of particles was good, and PDI was 0.005 (3) respectively ^# Sample) and 0.028 (2) ^# Sample).

Sample No. 4 ^# The rate of anti-solvent water addition compared to sample 2 ^# The preparation process is reduced by one time. It was found that the lower the rate of addition of the solvent aqueous phase, the larger the particle diameter of the synthesis. Due to the reduced rate of additionSample No. 4 ^# The particle size of the nano-particles is 83.12nm, but the particle concentration PDI of the nano-particles is higher and reaches 0.03.

And sample 2 ^# In contrast, 5 ^# The temperature of the reaction was increased mainly during the preparation of the samples, and we found 5 ^# The sample had a particle size of 83.32nm, a concentration of PDI of 0.016, and the prepared particle size was greater than 2 ^# The sample, and therefore, the reaction temperature is increased, which accelerates the polymerization reaction between the silicon sources, thereby increasing the size of the prepared particles.

In contrast to the above preparation process, in example 6, the base, the organic silicon source and the solvent were mixed together and then reacted by adding the aqueous phase, and as a result, it was found that the prepared particles had a size of 122.9nm and a relatively concentrated distribution of the particles, having a PDI of 0.028. The process provided by the invention is also verified to be capable of preparing uniform nano silicon oxide particles.

The above-mentioned sample 1 prepared this time ^# ～6 ^# The electron scanning characterization figures 9-14 show that the particles of the nano silicon oxide prepared by the reverse processing technology are all spherical particles, the sphericity of the particles is higher, and the distribution of the particles is more concentrated.

For the solids content of the process proposed by the invention, test example 2 shows that sample 2 is present ^# And 3 ^# The solid contents of (a) were 7.2wt.% and 12.4wt.%, respectively, the uniformity and sphericity of the nanoparticles increased to different extents as the solid contents increased, and for sample 3 ^# The metal ion content of the aqueous solution system is less than 151ppb, and the aqueous solution system completely meets the requirements of the ultra-high purity nano silicon oxide.

As can be seen from comparative examples 1,2, use is made of

The forward process, as shown in fig. 15 and 16, can achieve uniform spherical nanoparticle preparation with the silica solids content controlled below 6wt.%, however, when the solids content is 7.2wt.%In time, both the uniformity and sphericity of the nanoparticles decreased to varying degrees.

Therefore, the preparation method of the ultra-high purity uniform spherical nano silica particles provided by the invention can realize controllable preparation of the spherical nano silica particles with the size of 30-150 nm, and the prepared nano particles have the characteristics of narrow distribution, high uniformity, PDI (PDI) of less than 0.1, high sphericity and the like, the solid content of the prepared nano silica particles is 7-15 wt%, and the content of metal ions can be reduced to be less than 1ppm.

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. The preparation method of the nanometer silicon oxide particles is characterized in that an aqueous phase solution is added into a raw material containing an organic silicon source, and the raw material is heated and reacted to obtain the nanometer silicon oxide particles;

the aqueous phase solution is selected from one of water and an aqueous solution containing a pH regulator.

2. The method according to claim 1,

the organic silicon source is selected from at least one of formula I;

wherein R is ₁ ，R ₂ ，R ₃ Is independently selected from C _1-4 Alkoxy, hydrophobic groups, hydrophilic groups, silicon-containing groups;

R ₄ is selected from C _1-4 One of alkyl groups;

the above-mentionedThe hydrophobic group is selected from C _1-3 Alkyl, phenyl, C _2-3 One of the epoxy groups of (a);

the hydrophilic group is selected from one of aminopropyl, mercaptopropyl and chloropropyl;

3. The method according to claim 1, wherein the source material containing the organic silicon source comprises an organic base I, an organic solvent;

the organic alkali is selected from at least one of monoethanolamine, diethanolamine, triethylamine, diethylamine, pyridine, isopropanolamine, tetraethylammonium hydroxide, triethylenediamine and morpholine;

4. The method according to claim 1,

the pH value of the aqueous phase solution is 7-12;

preferably, the reaction temperature is 55 to 95 ℃.

5. The method according to claim 4, wherein the ratio of the molar amount of water to the molar amount of the organic silicon source in the aqueous solution is 4 to 100; wherein the molar amount of the organic silicon source is based on the molar amount of the silicon oxide.

6. The production method according to claim 4,

the adding speed of the aqueous phase solution is unit mass of reaction liquid, and the mass of the aqueous phase added per hour is 0.2-50 kg;

preferably, the pH regulator is selected from at least one of inorganic base and organic base II;

the organic base II is one or more selected from monoethanolamine, diethanolamine, triethylamine, diethylamine, isopropanolamine, tetraethylammonium hydroxide, triethylenediamine and morpholine.

7. The method for preparing according to claim 1, further comprising aging;

the aging temperature is 55-95 ℃; the aging time is 0.5-4 hr.

8. Nanosilica particles prepared by the method of any of claims 1 to 7.

9. The nano silica particles according to claim 8, wherein the micro morphology of the nano silica particles is spherical and the particle size is 30 to 150nm; PDI <0.1;

preferably, the solid content of the nano silicon oxide particles is 7wt.% to 20wt.%,

further preferably, the solid content ranges from 7wt.% to 15wt.%.

10. The nanosilica particles of claim 8,

the content of metal ions in the nano silicon oxide particles is less than 1ppm;