Effects of impeller speed on synthesis of monodisperse silica particles

Shu Saeki, Daisuke Nagao, Mikio Konno

Research output: Contribution to journalArticlepeer-review

Abstract

Monodisperse silica particles were prepared by hydrolysis and condensation of tetraethylorthosilicate (TEOS) at various impeller speeds up to 600 rpm to study the effects of impeller speed on particle size distribution. Ammonia-catalyzed reactions of TEOS were carried out in an ethanol-water solution at a water concentration of 11.0 kmol/m3, ammonia concentrations of 0.5 and 1.0 kmol/m3, and TEOS concentrations of 0. 2 and 0.4 kmol/m3 in the presence or absence of an electrolyte (KCl). When the final particles prepared were small, the particle size hardly depended on impeller speed; but, as the size of final particles increased, the particle size more strongly depended on impeller speed, and an increase in impeller speed increased the size of final particles. This impeller speed dependence is considered to be caused by sheer flocculation, which dominates over Brownian flocculation in the case of large particles. When particle size was increased by the addition of KCl, agitation at high impeller speeds brought about excessive coagulation, resulting in generation of hard aggregates and disappearance of spherical particles.

Original languageEnglish
Pages (from-to)200-203
Number of pages4
Journalkagaku kogaku ronbunshu
Volume31
Issue number3
DOIs
Publication statusPublished - 2005 May 1

Keywords

  • Aggregation
  • Impeller Speed
  • Monodisperse Particle
  • Silica Particle
  • Silicon Alkoxide
  • Tetraethylorthosilicate

ASJC Scopus subject areas

  • Materials Science (miscellaneous)

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