阅读说明：本技术 一种高分散性纳米二氧化硅及其制备方法 (High-dispersity nano silicon dioxide and preparation method thereof ) 是由 陈淑英 杨浩泽 梁伟虹 邱煌庆 于 2019-11-14 设计创作，主要内容包括：本发明公开了一种高分散性纳米二氧化硅及其制备方法,属于二氧化硅材料制备技术领域。本发明首先以亚麻纤维为原料,将其粉碎后再进行蒸汽爆破,得到爆破产物,接着将爆破产物和果胶酶以及木聚糖酶混合酶解得到酶解产物,随后将酶解产物分别进行酸处理和碱处理反应后得到反应产物,接着以硅酸钠和盐酸为原料,并加入本发明的反应产物,采用水热法合成了高分散性的纳米二氧化硅,最后煅烧去除木质素,最终得到高分散性的纳米二氧化硅,本发明制得的纳米二氧化硅具有极佳的分散性,不容易团聚,并且粒径均一,具有广阔的应用前景。(The invention discloses high-dispersity nano silicon dioxide and a preparation method thereof, and belongs to the technical field of silicon dioxide material preparation. Firstly, flax fibers are taken as raw materials, the flax fibers are crushed and then subjected to steam explosion to obtain an explosion product, then the explosion product, pectinase and xylanase are mixed and subjected to enzymolysis to obtain an enzymolysis product, then the enzymolysis product is subjected to acid treatment and alkali treatment respectively to obtain a reaction product, then sodium silicate and hydrochloric acid are taken as raw materials, the reaction product is added, a hydrothermal method is adopted to synthesize high-dispersity nano silicon dioxide, and finally, lignin is removed through calcination, and the high-dispersity nano silicon dioxide is finally obtained.)

1. A high-dispersity nano silicon dioxide is characterized in that: is prepared from reaction product, sodium silicate solution and hydrochloric acid.

2. The highly dispersible nanosilica as claimed in claim 1, wherein: the reaction product is prepared from flax fiber, xylanase, pectinase, hydrochloric acid and sodium hydroxide solution.

3. A preparation method of high-dispersity nano silicon dioxide is characterized by comprising the following specific preparation steps:

(1) preparing a reaction product;

(2) and (3) preparing high-dispersity nano silicon dioxide.

4. The preparation method of high-dispersity nano-silica according to claim 3 is characterized by comprising the following specific preparation steps:

(1) preparation of reaction product:

weighing flax fibers, putting the flax fibers into a tissue grinder, grinding to obtain mixed ground materials, putting the mixed ground materials into a steam explosion tank, and carrying out steam explosion to obtain explosion products;

mixing the blasting product, xylanase and pectinase, putting the mixture into an enzymolysis tank, standing for enzymolysis, and obtaining an enzymolysis product after the enzymolysis is finished;

mixing the obtained enzymolysis product and hydrochloric acid, putting the mixture into a three-neck flask with a stirrer and a thermometer, putting the three-neck flask into a water bath, stirring and reacting at normal temperature to obtain a reactant, adding a sodium hydroxide solution into the three-neck flask to adjust the pH value to 9-10, and continuing stirring and reacting to obtain a reaction product;

(2) preparing high-dispersity nano silicon dioxide:

mixing the obtained reaction product with a sodium silicate solution, putting the mixture into a reaction kettle, adjusting the pH to 2-3 with hydrochloric acid, and stirring for reaction;

after the stirring reaction is finished, heating the reaction kettle to raise the temperature, continuing stirring the reaction, filtering and separating the reaction product after the reaction is finished to obtain filter residues, and washing the obtained filter residues with absolute ethyl alcohol;

and after the washing is finished, putting the mixture into an oven, drying the mixture to constant weight, transferring the dried filter residue into a sintering furnace, preserving heat, sintering and discharging the mixture to obtain the high-dispersity nano silicon dioxide.

5. The preparation method of high-dispersity nano-silica according to claim 3 is characterized by comprising the following specific preparation steps:

(1) preparation of reaction product:

weighing flax fibers, putting the flax fibers into a tissue grinder, grinding for 1-2 hours to obtain a mixed ground material, putting the mixed ground material into a steam explosion tank, and carrying out steam explosion to obtain an explosion product;

mixing the blasting product, xylanase and pectinase according to a mass ratio of 20:1:1, then loading the mixture into an enzymolysis tank, then placing the enzymolysis tank into a thermostat at the temperature of 40-50 ℃, standing for enzymolysis for 12-15 hours, and obtaining an enzymolysis product after enzymolysis is finished;

and (3) mixing the obtained enzymolysis product with hydrochloric acid with the concentration of 0.1mol/L according to the mass ratio of 1: 5, mixing, putting into a three-neck flask with a stirrer and a thermometer, putting the three-neck flask into a water bath, stirring and reacting for 10-12 h at normal temperature to obtain a reactant, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the three-neck flask to adjust the pH to 9-10, and continuously stirring and reacting for 1-2 h at 30-40 ℃ to obtain a reaction product;

(2) preparing high-dispersity nano silicon dioxide:

mixing the obtained reaction product with a 30% sodium silicate solution according to a mass ratio of 1:8, then putting the mixture into a reaction kettle, adjusting the pH to 2-3 by using 1mol/L hydrochloric acid, and stirring and reacting at a rotating speed of 200-300 r/min for 15-20 min;

after the stirring reaction is finished, heating the reaction kettle, continuing stirring and reacting for 1-2 hours at the rotating speed of 200-300 r/min, filtering and separating to obtain filter residues after the reaction is finished, and washing the obtained filter residues for 3-5 times by using absolute ethyl alcohol;

and after the washing is finished, putting the silicon dioxide into an oven, drying the silicon dioxide at 105-110 ℃ to constant weight, transferring the dried filter residue into a sintering furnace, heating to 200-300 ℃, carrying out heat preservation sintering for 20-30 min, and discharging to obtain the high-dispersity nano silicon dioxide.

6. The method for preparing high-dispersibility nano-silica according to claim 5, wherein: in the step of preparing the reaction product, the pressure for steam explosion is 1.8-2.0 MPa, and the temperature is 180-190 ℃.

7. The method for preparing high-dispersibility nano-silica according to claim 5, wherein: in the preparation step of the high-dispersity nano silicon dioxide, the temperature for heating the reaction kettle is 250-300 ℃.

Technical Field

The invention discloses high-dispersity nano silicon dioxide and a preparation method thereof, and belongs to the technical field of silicon dioxide material preparation.

Background

Basic properties of nanosilica: SiO 2₂White fluffy powder, porosity, no toxicity, no smell, no pollution and high temperature resistance. Meanwhile, the chemical inertness and the special thixotropic property of the rubber obviously improve the tensile strength, the tear resistance and the wear resistance of a rubber product, and the strength of the improved rubber is improved by tens of times. Rheology and thixotropy control of liquid systems, adhesives, polymers, etc., use as anti-settling, thickening, anti-sagging aids, reinforcement of HCR and RTV-2K silicone rubbers, use to regulate free flow and as anti-blocking agents to improve powder properties, etc.

The production method comprises the following steps: gas phase processes are also known as pyrolysis, dry or combustion processes. The raw materials are silicon tetrachloride, oxygen and hydrogen which are reacted at high temperature. Air and hydrogen are respectively pressurized, separated, cooled and dehydrated, dried by silica gel, dedusted and filtered, and then are sent into a synthetic hydrolysis furnace. The silicon tetrachloride raw material is sent to a rectifying tower for rectification, then is heated and evaporated in an evaporator, and is sent to a synthetic hydrolysis furnace by taking dried and filtered air as a carrier. After the silicon tetrachloride is gasified at high temperature, the silicon tetrachloride and a certain amount of hydrogen and oxygen are subjected to gas phase hydrolysis at the high temperature of about 1800 ℃; at the moment, the generated nano silicon dioxide particles are extremely fine and form aerosol with gas, so that the aerosol is not easy to trap, and the nano silicon dioxide particles are firstly gathered into larger particles in a collector, then are collected by a cyclone separator and then are sent into a deacidification furnace, and the nano silicon dioxide is blown by nitrogen-containing air until the pH value is 4-6, so that a finished product is obtained.

The nano silicon dioxide is one of the earliest produced nano materials and is also a nano powder material produced in large scale in the world at present. As a good structure and function material, however, the effect of the existing nano-silica is still not ideal in various application processes, but the reason for this is probably that the easy agglomeration phenomenon of the nano-material inhibits the full exertion of the nano-superfine effect, especially the large amount of hydroxyl groups on the surface of the nano-silica makes the surface energy of the nano-silica larger, and further makes the nano-silica always prone to agglomeration.

Therefore, some improvements are made in the prior art for the above phenomena, for example, the gefeng silk and the like are used for modifying the surface of the ultrafine silica by using an alcohol ester method to obtain the ultrafine nano silica with a hydrophobic surface, see university of Anhui science and engineering (Nature science edition), but the method needs to be carried out at a higher temperature (225 ℃) and a certain pressure (3MPa), and the hydrophobicity is only 30-40%. Bogusaw Buszewski et al, through the research on the properties and preparation method of silica gel aggregates, surface modification of silica with alcohol compounds, the degree of modification can be detected by elemental analysis, i.e. by calculating the density of the coating on the surface of the complex, the modified structure is determined by solid-state NMR and FT-IR optical instruments, the phase transition is revealed by thermal stability analysis, and the heterogeneous properties of the filler surface are verified by chromatography tests, however, this method is as complicated as the aforementioned modification process and has high energy consumption, when the surface modification of nano-silica is carried out with boron amine compounds, the best effect is to treat the nano-silica at 500 ℃ for 3h, which can fix most of boron amine groups on the silica surface, and the boron amine modification makes the nano-silica as a rubber reinforcing filler, which, although the comprehensiveness can be improved, also requires a high-temperature surface treatment process at 500 ℃, the energy consumption is higher. Although isocyanate modified silicon dioxide is disclosed in the patent, the hydrophobicity is improved, the addition of fatty alcohol causes the wrapping of a long chain on an active group, the reaction is not thorough, and more silicon hydroxyl groups still remain, so that the prepared modified nano silicon dioxide material still can hardly meet the practical requirements in the aspects of heat resistance, adhesive property, electrical strength, mechanical strength and the like in the application of electrical insulating materials and heat-resistant materials.

Therefore, the invention of nano-silica with good dispersibility is necessary for the technical field of nano-material preparation.

Disclosure of Invention

The invention mainly solves the technical problem, and provides high-dispersity nano silicon dioxide and a preparation method thereof, aiming at the defects that in the existing nano silicon dioxide preparation process, due to the fact that the surface energy of a nano material is larger, the finally prepared nano silicon dioxide is easy to agglomerate, the particle size distribution range is large, and the dispersity is poor. In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a high-dispersity nano silicon dioxide is prepared from reaction product, sodium silicate solution and hydrochloric acid.

A high-dispersity nano-silicon dioxide is prepared from flax fibres, xylanase, pectase, hydrochloric acid and sodium hydroxide solution.

A preparation method of high-dispersity nano silicon dioxide comprises the following specific preparation steps:

(1) preparing a reaction product;

(2) and (3) preparing high-dispersity nano silicon dioxide.

A preparation method of high-dispersity nano silicon dioxide comprises the following specific preparation steps:

(1) preparation of reaction product:

weighing flax fibers, putting the flax fibers into a tissue grinder, grinding to obtain mixed ground materials, putting the mixed ground materials into a steam explosion tank, and carrying out steam explosion to obtain explosion products;

mixing the blasting product, xylanase and pectinase, putting the mixture into an enzymolysis tank, standing for enzymolysis, and obtaining an enzymolysis product after the enzymolysis is finished;

mixing the obtained enzymolysis product and hydrochloric acid, putting the mixture into a three-neck flask with a stirrer and a thermometer, putting the three-neck flask into a water bath, stirring and reacting at normal temperature to obtain a reactant, adding a sodium hydroxide solution into the three-neck flask to adjust the pH value to 9-10, and continuing stirring and reacting to obtain a reaction product;

(2) preparing high-dispersity nano silicon dioxide:

mixing the obtained reaction product with a sodium silicate solution, putting the mixture into a reaction kettle, adjusting the pH to 2-3 with hydrochloric acid, and stirring for reaction;

after the stirring reaction is finished, heating the reaction kettle to raise the temperature, continuing stirring the reaction, filtering and separating the reaction product after the reaction is finished to obtain filter residues, and washing the obtained filter residues with absolute ethyl alcohol;

and after the washing is finished, putting the mixture into an oven, drying the mixture to constant weight, transferring the dried filter residue into a sintering furnace, preserving heat, sintering and discharging the mixture to obtain the high-dispersity nano silicon dioxide.

A preparation method of high-dispersity nano silicon dioxide comprises the following specific preparation steps:

(1) preparation of reaction product:

weighing flax fibers, putting the flax fibers into a tissue grinder, grinding for 1-2 hours to obtain a mixed ground material, putting the mixed ground material into a steam explosion tank, and carrying out steam explosion to obtain an explosion product;

mixing the blasting product, xylanase and pectinase according to a mass ratio of 20:1:1, then loading the mixture into an enzymolysis tank, then placing the enzymolysis tank into a thermostat at the temperature of 40-50 ℃, standing for enzymolysis for 12-15 hours, and obtaining an enzymolysis product after enzymolysis is finished;

and (3) mixing the obtained enzymolysis product with hydrochloric acid with the concentration of 0.1mol/L according to the mass ratio of 1: 5, mixing, putting into a three-neck flask with a stirrer and a thermometer, putting the three-neck flask into a water bath, stirring and reacting for 10-12 h at normal temperature to obtain a reactant, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the three-neck flask to adjust the pH to 9-10, and continuously stirring and reacting for 1-2 h at 30-40 ℃ to obtain a reaction product;

(2) preparing high-dispersity nano silicon dioxide:

mixing the obtained reaction product with a 30% sodium silicate solution according to a mass ratio of 1:8, then putting the mixture into a reaction kettle, adjusting the pH to 2-3 by using 1mol/L hydrochloric acid, and stirring and reacting at a rotating speed of 200-300 r/min for 15-20 min;

after the stirring reaction is finished, heating the reaction kettle, continuing stirring and reacting for 1-2 hours at the rotating speed of 200-300 r/min, filtering and separating to obtain filter residues after the reaction is finished, and washing the obtained filter residues for 3-5 times by using absolute ethyl alcohol;

and after the washing is finished, putting the silicon dioxide into an oven, drying the silicon dioxide at 105-110 ℃ to constant weight, transferring the dried filter residue into a sintering furnace, heating to 200-300 ℃, carrying out heat preservation sintering for 20-30 min, and discharging to obtain the high-dispersity nano silicon dioxide.

In the preparation step of the reaction product, the pressure for steam explosion is 1.8-2.0 MPa, and the temperature is 180-190 ℃.

In the preparation step of the high-dispersity nano silicon dioxide, a reaction kettle is heated to the temperature of 250-300 ℃.

The beneficial technical effects of the invention are as follows:

(1) firstly, flax fibers are taken as raw materials, the flax fibers are crushed and then subjected to steam explosion to obtain an explosion product, then the explosion product, pectinase and xylanase are mixed and subjected to enzymolysis to obtain an enzymolysis product, then the enzymolysis product is subjected to acid treatment and alkali treatment respectively to obtain a reaction product, then sodium silicate and hydrochloric acid are taken as raw materials, the reaction product is added, high-dispersity nano silicon dioxide is synthesized by adopting a hydrothermal method, finally, lignin is removed by calcination, and finally, the high-dispersity nano silicon dioxide is obtained. According to the invention, the enzymatic hydrolysis product is sequentially subjected to acid treatment and alkali treatment, macromolecular polysaccharide in the enzymatic hydrolysis product is hydrolyzed into monosaccharide under an acidic condition, part of the monosaccharide is oxidized into saccharic acid, the substances are further reacted under an alkaline condition to generate sodium saccharic acid, and the treated reaction product contains lignin with a large number of hydroxyl groups;

(2) in addition, sodium gluconate molecules generated in the reaction product have amphiphilicity and are adsorbed on the surface of nano silicon dioxide particles after the nano silicon dioxide is formed, and the adsorption of the amphiphilicity substances effectively reduces the free energy on the surface of the nano silicon dioxide particles, so that the dispersibility of the nano silicon dioxide is improved, and the finally prepared nano silicon dioxide has the advantages of fine and uniform particle size, excellent dispersibility and wide application prospect.

Detailed Description

Preparing an explosion product:

weighing flax fibers, putting the flax fibers into a tissue grinder, grinding for 1-2 hours to obtain a mixed ground material, putting the mixed ground material into a steam explosion tank, and performing steam explosion under the conditions that the pressure is 1.8-2.0 MPa and the temperature is 180-190 ℃ to obtain an explosion product;

preparation of an enzymolysis product:

mixing the blasting product, xylanase and pectinase according to a mass ratio of 20:1:1, then loading the mixture into an enzymolysis tank, then placing the enzymolysis tank into a thermostat at the temperature of 40-50 ℃, standing for enzymolysis for 12-15 hours, and obtaining an enzymolysis product after enzymolysis is finished;

preparation of reaction product:

and (3) mixing the obtained enzymolysis product with hydrochloric acid with the concentration of 0.1mol/L according to the mass ratio of 1: 5, mixing, putting into a three-neck flask with a stirrer and a thermometer, putting the three-neck flask into a water bath, stirring and reacting for 10-12 h at normal temperature to obtain a reactant, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the three-neck flask to adjust the pH to 9-10, and continuously stirring and reacting for 1-2 h at 30-40 ℃ to obtain a reaction product;

preparing high-dispersity nano silicon dioxide:

(1) mixing the obtained reaction product with a 30% sodium silicate solution according to a mass ratio of 1:8, then putting the mixture into a reaction kettle, adjusting the pH to 2-3 by using 1mol/L hydrochloric acid, and stirring and reacting at a rotating speed of 200-300 r/min for 15-20 min;

(2) after the stirring reaction is finished, heating the reaction kettle to 250-300 ℃, continuously stirring and reacting for 1-2 hours at a rotating speed of 200-300 r/min, filtering and separating to obtain filter residues after the reaction is finished, and washing the obtained filter residues for 3-5 times by using absolute ethyl alcohol;

(3) and after the washing is finished, putting the silicon dioxide into an oven, drying the silicon dioxide at 105-110 ℃ to constant weight, transferring the dried filter residue into a sintering furnace, heating to 200-300 ℃, carrying out heat preservation sintering for 20-30 min, and discharging to obtain the high-dispersity nano silicon dioxide.

Example 1

Preparing an explosion product:

weighing flax fibers, putting the flax fibers into a tissue grinder, grinding for 1h to obtain a mixed ground substance, putting the mixed ground substance into a steam explosion tank, and performing steam explosion under the conditions that the pressure is 1.8MPa and the temperature is 180 ℃ to obtain an explosion product;

preparation of an enzymolysis product:

mixing the blasting product, xylanase and pectinase according to a mass ratio of 20:1:1, then loading into an enzymolysis tank, then placing the enzymolysis tank into a thermostat at the temperature of 40 ℃, standing for enzymolysis for 12 hours, and obtaining an enzymolysis product after enzymolysis is finished;

preparation of reaction product:

and (3) mixing the obtained enzymolysis product with hydrochloric acid with the concentration of 0.1mol/L according to the mass ratio of 1: 5, mixing, putting into a three-neck flask with a stirrer and a thermometer, putting the three-neck flask into a water bath, stirring and reacting for 10 hours at normal temperature to obtain a reactant, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the three-neck flask to adjust the pH value to 9, and continuously stirring and reacting for 1 hour at 30 ℃ to obtain a reaction product;

preparing high-dispersity nano silicon dioxide:

(1) mixing the obtained reaction product with 30% sodium silicate solution according to the mass ratio of 1:8, putting into a reaction kettle, adjusting the pH to 2 by using 1mol/L hydrochloric acid, and stirring at the rotating speed of 200r/min for reaction for 15 min;

(2) after the stirring reaction is finished, heating the reaction kettle to 250 ℃, continuously stirring and reacting for 1h at the rotating speed of 200r/min, filtering and separating to obtain filter residues after the reaction is finished, and washing the obtained filter residues for 3 times by using absolute ethyl alcohol;

(3) and after the washing is finished, putting the silicon dioxide into an oven, drying the silicon dioxide at 105 ℃ to constant weight, transferring the dried filter residue into a sintering furnace, heating to 200 ℃, carrying out heat preservation sintering for 20min, and discharging to obtain the high-dispersity nano silicon dioxide.

Example 2

Preparing an explosion product:

weighing flax fibers, putting the flax fibers into a tissue grinder, grinding for 1h to obtain a mixed ground substance, putting the mixed ground substance into a steam explosion tank, and performing steam explosion under the conditions of pressure of 1.9MPa and temperature of 185 ℃ to obtain an explosion product;

preparation of an enzymolysis product:

mixing the blasting product, xylanase and pectinase according to a mass ratio of 20:1:1, then loading into an enzymolysis tank, then placing the enzymolysis tank into a thermostat at the temperature of 45 ℃, standing for enzymolysis for 14h, and obtaining an enzymolysis product after enzymolysis is finished;

preparation of reaction product:

and (3) mixing the obtained enzymolysis product with hydrochloric acid with the concentration of 0.1mol/L according to the mass ratio of 1: 5, mixing, putting into a three-neck flask with a stirrer and a thermometer, putting the three-neck flask into a water bath, stirring and reacting for 11 hours at normal temperature to obtain a reactant, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the three-neck flask to adjust the pH value to 10, and continuously stirring and reacting for 2 hours at 35 ℃ to obtain a reaction product;

preparing high-dispersity nano silicon dioxide:

(1) mixing the obtained reaction product with a 30% sodium silicate solution according to a mass ratio of 1:8, putting into a reaction kettle, adjusting the pH to 2 by using 1mol/L hydrochloric acid, and stirring at a rotating speed of 250r/min for reacting for 18 min;

(2) after the stirring reaction is finished, heating the reaction kettle to 280 ℃, continuously stirring and reacting for 2 hours at the rotating speed of 250r/min, filtering and separating to obtain filter residues after the reaction is finished, and washing the obtained filter residues for 4 times by using absolute ethyl alcohol;

(3) and after the washing is finished, putting the silicon dioxide into an oven, drying the silicon dioxide at 108 ℃ to constant weight, transferring the dried filter residue into a sintering furnace, heating the silicon dioxide to 250 ℃, carrying out heat preservation sintering for 25min, and discharging the silicon dioxide to obtain the high-dispersity nano silicon dioxide.

Example 3

Preparing an explosion product:

weighing flax fibers, putting the flax fibers into a tissue grinder, grinding for 2 hours to obtain a mixed ground substance, putting the mixed ground substance into a steam explosion tank, and performing steam explosion under the conditions that the pressure is 2.0MPa and the temperature is 190 ℃ to obtain an explosion product;

preparation of an enzymolysis product:

mixing the blasting product, xylanase and pectinase according to a mass ratio of 20:1:1, then loading into an enzymolysis tank, then placing the enzymolysis tank into a thermostat at 50 ℃, standing for enzymolysis for 15h, and obtaining an enzymolysis product after enzymolysis is finished;

preparation of reaction product:

and (3) mixing the obtained enzymolysis product with hydrochloric acid with the concentration of 0.1mol/L according to the mass ratio of 1: 5, mixing, putting into a three-neck flask with a stirrer and a thermometer, putting the three-neck flask into a water bath, stirring and reacting for 12 hours at normal temperature to obtain a reactant, adding a sodium hydroxide solution with the concentration of 0.5mol/L into the three-neck flask to adjust the pH value to 10, and continuously stirring and reacting for 2 hours at 40 ℃ to obtain a reaction product;

preparing high-dispersity nano silicon dioxide:

(1) mixing the obtained reaction product with a 30% sodium silicate solution according to a mass ratio of 1:8, putting into a reaction kettle, adjusting the pH to 3 by using 1mol/L hydrochloric acid, and stirring at a rotating speed of 300r/min for reaction for 20 min;

(2) after the stirring reaction is finished, heating the reaction kettle to 300 ℃, continuously stirring and reacting for 2 hours at the rotating speed of 300r/min, filtering and separating to obtain filter residues after the reaction is finished, and washing the obtained filter residues for 5 times by using absolute ethyl alcohol;

(3) and after the washing is finished, putting the silicon dioxide into an oven, drying the silicon dioxide at 110 ℃ to constant weight, transferring the dried filter residue into a sintering furnace, heating the silicon dioxide to 300 ℃, carrying out heat preservation sintering for 30min, and discharging the silicon dioxide to obtain the high-dispersity nano silicon dioxide.

Comparative example 1: the preparation was similar to inventive example 1, except that the reaction product prepared according to the invention was not used.

The performance of the nano-silica prepared by the invention and the performance of the nano-silica in the comparative example were respectively detected, and the detection results are shown in table 1:

detection method

And (3) testing the dispersibility: taking 10mg of the products of examples 1-3 and the comparative example prepared by the invention, respectively adding the products into 10mL of water, performing ultrasonic dispersion for 30 minutes to obtain a suspension, standing, and when obvious layering occurs, recording the storage time, wherein the longer the storage time is, the better the dispersibility is.

TABLE 1 Performance test results

As can be seen from the detection data in the table above, the nano silicon dioxide prepared by the invention has excellent dispersibility, is not easy to agglomerate, has uniform particle size and has wide application prospect.