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CN-121990579-A - Method for preparing monodisperse and particle size controllable silicon dioxide microspheres based on seed growth method

CN121990579ACN 121990579 ACN121990579 ACN 121990579ACN-121990579-A

Abstract

The invention discloses a method for preparing monodisperse and particle size controllable silicon dioxide microspheres based on a seed growth method, which combines a St and a Baber method with a sodium silicate precipitation method, ensures the monodispersity of initial seeds by using the St and the Baber method, realizes subsequent low-cost and large-scale growth by using sodium silicate, and effectively solves the problems of high cost and complex steps in the conventional St and Baber method amplified production. The invention effectively solves the problem of explosive homogeneous nucleation caused by the severe pH change of the traditional sodium silicate method by precisely controlling the reaction kinetics. By keeping the rate of silicate ion generation always lower than its heterogeneous deposition rate on the seed surface, secondary nucleation is thoroughly inhibited and pure heterogeneous growth of silicon species entirely on the seed surface is achieved. The method ensures that the final product inherits the monodispersity of seeds, realizes accurate and controllable amplification of the particle size of the microsphere, and finally obtains the silica microsphere with excellent monodispersity and controllable particle size.

Inventors

  • WANG XIUJUAN
  • ZHANG PENGWEI
  • MA SHENGHUA
  • HOU MINMIN
  • FENG PINGPING

Assignees

  • 西安蓝桥新能源科技有限公司

Dates

Publication Date
20260508
Application Date
20260211

Claims (10)

  1. 1. A method for preparing monodisperse and particle size controllable silicon dioxide microspheres based on a seed growth method is characterized by comprising the following steps: Step 1, uniformly mixing a nonpolar solvent with deionized water, adding organic silane, uniformly stirring, adding organic alkali, uniformly stirring to obtain a transparent precursor solution, wherein the nonpolar solvent is selected from mixed liquid of any two of ethanol, methanol and isopropanol, the organic silane is selected from mixture of any three of tetraethoxysilane, methyltrimethoxysilane and methylsilane, and the organic alkali is selected from mixed liquid of any two of ammonia water, triethanolamine and N-methylpyrrolidone; Step 2, hydrolyzing the transparent precursor solution in the step 1 at 60-80 ℃ for 3-5 hours to obtain a silica seed dispersion; Step 3, dropwise adding a sodium silicate aqueous solution with the concentration of 1-3 mol/L into the silicon dioxide seed dispersion liquid in the step 2 under the stirring condition, adding deionized water to control the pH of the reaction liquid to be 9-11, and continuously stirring and reacting for 5-8 hours to obtain a grown silicon dioxide dispersion liquid; And 4, performing primary separation on the silicon dioxide dispersion liquid grown in the step 3 by adopting a gravity sedimentation method, performing centrifugal washing by using distilled water and absolute ethyl alcohol, and performing freeze drying on the obtained precipitate at a temperature gradient of-5 to-20 ℃ for 12-24 hours to obtain the monodisperse silicon dioxide microsphere powder.
  2. 2. The method for preparing monodisperse particle size controllable silica microspheres based on a seed growth method according to claim 1, wherein in the step 1, the volume ratio of the nonpolar solvent, deionized water, organosilane and organic base is 100:25-40:2-5:6-10.
  3. 3. The method for preparing monodisperse particle size controllable silica microspheres based on the seed growth method according to claim 1 or 2, wherein the nonpolar solvent is selected from a mixed solution of any two of ethanol, methanol and isopropanol in a volume ratio of 1:1-2.
  4. 4. The method for preparing monodisperse particle size controllable silicon dioxide microspheres based on the seed growth method according to claim 1 or 2, wherein the organosilane is a mixed solution of any three of tetraethoxysilane, tetramethylsilicate, methyltrimethoxysilane and methylsilane in a volume ratio of 1:0.5-2:0.3-3.
  5. 5. The method for preparing monodisperse particle size controllable silica microspheres based on the seed growth method according to claim 1 or 2, wherein the organic base is selected from any two mixed solutions of ammonia water, triethanolamine and N-methylpyrrolidone in a volume ratio of 1:1-2.
  6. 6. The method for preparing monodisperse and particle size controllable silica microspheres based on a seed growth method according to claim 1, wherein in step 2, the concentration of silica seeds in the silica seed dispersion is 0.1-0.5 mol/L.
  7. 7. The method for preparing monodisperse and particle size controllable silica microspheres based on a seed growth method according to claim 1 or 6, wherein in the step 3, the volume ratio of the silica seed dispersion liquid to the sodium silicate aqueous solution is 1:0.8-4.
  8. 8. The method for preparing monodisperse particle size controllable silica microspheres based on the seed growth method according to claim 1, wherein in step 3, the stirring speed is 600-1000 r/min.
  9. 9. The method for preparing monodisperse particle size controllable silica microspheres based on the seed growth method according to claim 1, wherein in step 4, the centrifugal washing is performed at a rotational speed of 5000-8000 r/min for 6-10 min, and the washing process is repeatedly performed until precipitation is clean.
  10. 10. The method for preparing monodisperse particle size controllable silica microspheres based on a seed growth method according to claim 1, wherein in the step 4, the obtained precipitate is freeze-dried at-5 to-10 ℃ for 10-12 hours, thawed and freeze-dried at-15 to-20 ℃ for 4-8 hours.

Description

Method for preparing monodisperse and particle size controllable silicon dioxide microspheres based on seed growth method Technical Field The invention belongs to the technical field of silicon dioxide preparation, and particularly relates to a method for preparing monodisperse silicon dioxide microspheres with controllable particle size based on a seed growth method. Background The silica microsphere has wide application in the fields of chromatographic packing, medicine carrier, paint additive, photon crystal, standard metering and the like due to good chemical stability, biocompatibility, easy functionalization and unique optical characteristics. Monodispersity (uniform size distribution) and precise control of particle size are critical in determining their performance. At present, the conventional St-ber method (using tetraethyl orthosilicate (TEOS) as a silicon source) can prepare silicon dioxide microspheres with excellent monodispersity in an alcohol-water-ammonia system, but when large-size (> 2 μm) particles are prepared, a large amount of expensive TEOS and organic solvents are required to be consumed, the cost is high, the multiple growth steps are complicated, and the large-scale production is not facilitated. In addition, although the sodium silicate (water glass) method widely adopted in industry is low in cost and easy to obtain, the nucleation and growth dynamics are difficult to control by the traditional acidification precipitation process, the products are mostly agglomerates or amorphous powder, monodisperse spherical particles cannot be directly obtained, and the precise regulation and control of the particle size cannot be realized. Therefore, there is a strong need in the art for a silica microsphere preparation technique that can compromise "product monodispersity" with "process economies" and scalability. If the high-quality monodisperse small-particle-size silicon dioxide obtained by St ber method is used as 'seed', and the low-cost sodium silicate is used for controllable growth on the surface of the silicon dioxide, the silicon dioxide has great industrial application potential. However, how to achieve stable transfer of seeds from an alcohol phase system to an aqueous phase growth system and to effectively inhibit homogeneous nucleation of sodium silicate in the aqueous phase is a key challenge in achieving this technological path. Disclosure of Invention The invention aims to provide a preparation method of silica microspheres with both monodispersity and low cost and large scale. Aiming at the purposes, the preparation method of the silica microsphere provided by the invention comprises the following steps: The preparation method comprises the steps of 1, uniformly mixing a nonpolar solvent with deionized water, adding organic silane, uniformly stirring, adding organic base, uniformly stirring to obtain a transparent precursor solution, wherein the nonpolar solvent is selected from mixed liquid of any two of ethanol, methanol and isopropanol, the organic silane is selected from mixture of any three of tetraethoxysilane, methyltrimethoxysilane and methylsilane, and the organic base is selected from mixed liquid of any two of ammonia water, triethanolamine and N-methylpyrrolidone. And 2, hydrolyzing the transparent precursor solution in the step 1 at 60-80 ℃ for 3-5 hours to obtain a silica seed dispersion liquid. And 3, dropwise adding a sodium silicate aqueous solution with the concentration of 1-3 mol/L into the silicon dioxide seed dispersion liquid in the step 2 under the stirring condition, adding deionized water to control the pH of the reaction liquid to be 9-11, and continuously stirring and reacting for 5-8 hours to obtain the grown silicon dioxide dispersion liquid. And 4, performing primary separation on the silicon dioxide dispersion liquid grown in the step 3 by adopting a gravity sedimentation method, performing centrifugal washing by using distilled water and absolute ethyl alcohol, and performing freeze drying on the obtained precipitate at a temperature gradient of-5 to-20 ℃ for 12-24 hours to obtain the monodisperse silicon dioxide microsphere powder. In the step 1, the volume ratio of the nonpolar solvent, deionized water, organosilane and organic base is preferably 100:25-40:2-5:6-10. In step 1, the nonpolar solvent is preferably selected from a mixed solution of any two of ethanol, methanol and isopropanol in a volume ratio of 1:1-2. In step 1, the organosilane is preferably a mixed solution of any three of tetraethyl orthosilicate, tetramethyl orthosilicate, methyltrimethoxysilane and methylsilane in a volume ratio of 1:0.5-2:0.3-3. In step 1, the organic base is preferably selected from a mixed solution of any two of ammonia water, triethanolamine and N-methylpyrrolidone in a volume ratio of 1:1 to 2. In the step 2, the concentration of the silica seeds in the silica seed dispersion is preferably 0.1 to 0.5mol/L. In the step 3, the volume ratio of the si