Abstract

Objective SiO₂ microspheres have broad application prospects in pharmaceuticals， coatings， cosmetics， optoelectronics， and industrial catalysis due to their advantages such as high hardness， high packing density， good flowability， and low abrasion. However， traditional preparation methods mainly rely on tetraethyl orthosilicate （TEOS） as the silicon source， which presents problems such as high cost， low silicon content， and the use of large amounts of organic solvents during the reaction process. These limitations hinder large‑scale application and are inconsistent with the principles of green chemistry. Therefore， this study aims to develop a low-cost and green synthesis process based on inexpensive Na₂SiO₃ to replace the TEOS-based method， achieving sustainable production of high‑performance SiO₂ microspheres. By optimizing key parameters， the issues of poor morphology and easy agglomeration of microspheres prepared with Na₂SiO₃ as the silicon source are addressed， offering a feasible solution for industrial application.

Methods An ultrasonic cavitation‑assisted， polyethylene glycol （PEG）‑induced seed growth method was employed， using low‑cost Na₂SiO₃ as the silicon source， to systematically optimize process parameters such as PEG content， ultrasonic treatment， and aging time. The structure， morphology， and particle size of the SiO₂ microspheres were characterized using Fourier‑transform infrared spectroscopy （FTIR）， scanning electron microscopy （SEM）， and laser particle size analysis. Additionally， zeta potential analysis was combined to evaluate the stability of the particle dispersion system. The effects of PEG content， ultrasonic treatment， and aging time on the morphology， particle size， and dispersibility of microspheres were investigated.

Results and Discussion As a morphology‑directing agent， PEG not only effectively stabilized the precursor and particle surfaces through hydrogen bonding， but also provided steric hindrance effects. The synergistic effects of both stabilized the reaction system. The ultrasonic cavitation effect generated local high‑pressure zones and micro‑jets， which disrupted weak inter‑particle interactions and prevented agglomeration. The aging process followed the Ostwald ripening mechanism， promoting a more uniform particle size distribution. When the aging time reached 4 h， the absolute zeta potential value reached ‑51 mV， at which point the electrostatic repulsion between SiO₂ microspheres was strongest， effectively suppressing agglomeration.

Conclusion This study successfully develops a green synthesis process based on ultrasonic cavitation combined with PEG‑induced seeding， using inexpensive Na₂SiO₃ to replace TEOS to prepare high‑performance SiO₂ microspheres. The optimal process parameters are ultrasonic power of 500 W， PEG2000 dosage of 2 g， and aging time of 4 h. The obtained microspheres exhibit excellent sphericity， good dispersibility， and a median particle size of 3.6 μm. Through synergistic optimization of multiple parameters， this method overcomes the limitations of high cost and poor environmental friendliness of traditional processes， providing a low‑cost， scalable preparation strategy for SiO₂ microspheres in fields such as pharmaceuticals and coatings. Future research can explore the regulation of microsphere pore size and the extension of their applications in porous materials.

Keywords： sodium silicate； silica microsphere； ultrasonic-assisted

Get Citation: Peng Xiaofeng， Deng Jinming， Li Fuzhi， et al. Preparation of spherical silica induced by ultrasonic cavitation and polyethylene plycol［J］. China Powder Science and Technology， 2026， 32（4）： 1-9.

Received: 2025-09-27, Revised: 2026-03-17, Online: 2026-05-19.

DOI：10.13732/j.issn.1008-5548.2026.04.001

CLC No.：TB4；TQ324.8

Type Code: A

Serial No.：1008-5548（2026）04-0001-09