Kinetics study to identify reaction-controlled conditions for supercritical hydrothermal nanoparticle synthesis with flow-type reactors

Nobuaki Aoki, Ayato Sato, Hikari Sasaki, Andrzej Alexander Litwinowicz, Gimyeong Seong, Tsutomu Aida, Daisuke Hojo, Seiichi Takami, Tadafumi Adschiri

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Flow-type reactors are effective for the precise control of reaction conditions and high throughput production. To enhance the effectiveness of this process, the establishment of a design method is required. For this purpose, the effects of operating parameters on supercritical hydrothermal nanoparticle synthesis in a flow-type reactor were examined. Ceria nanoparticles were formed from 2.0 mM cerium nitrate at reaction temperatures ranging from 200 to 380 °C and with a flow rate of 11.6-37.5 mL/min. In addition, channel sizes of 0.3, 1.3, and 2.3 mm were used for the mixing point. Rapid mixing and higher temperatures were found to enable the formation of smaller nanoparticles. Furthermore, all experimental results were summarized using dimensionless numbers. Though the Reynolds number was related to the effect of mixing on particle formation, this number is independent of the reaction rate. Results were correlated using the Damköhler number, the ratio of reaction rate to mixing rate. From the threshold value of the Damköhler number, reaction-controlled conditions where the particle size was independent of the flow/mixing rate could be predicted.

Original languageEnglish
Pages (from-to)161-166
Number of pages6
JournalJournal of Supercritical Fluids
Volume110
DOIs
Publication statusPublished - 2016 Apr 1

Keywords

  • Damköhler number
  • Flow-type reactor
  • Kinetics
  • Mixing
  • Nanoparticle

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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