Effect of solid volume fraction on aggregation and breakage in colloidal suspensions in batch and continuous stirred tanks

Amgad S. Moussa, Miroslav Soos, Jan Sefcik, Massimo Morbidelli

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Aggregation and breakage of aggregates of fully destabilized polystyrene latex particles in turbulent flow was studied experimentally in both batch and continuous stirred tanks. Small-angle static light scattering (SASLS) was used to monitor the time evolution of two independent moments of the cluster mass distribution (CMD), namely, the mean radius of gyration and the zero angle scattered light intensity. In addition, information about the structure of the aggregates was obtained in terms of the static light scattering structure factor. It was observed that decreasing the solid volume fraction over more than one order of magnitude resulted in monotonically decreasing steady-state values of both moments of the CMD. Using a combination of batch operation and continuous dilution with particle-free solution in the stirred tank, it was found that the steady-state distributions were fully reversible upon changing the solid volume fraction. These observations indicate that the steady-state CMD in this system is controlled by the dynamic equilibrium between aggregation (with the second-order kinetics in cluster concentration) and breakage (with the first-order kinetics in cluster concentration). In addition, by dilution to very low solid volume fractions, we demonstrate the existence of a critical aggregate size below which breakage is negligible.

Original languageEnglish
Pages (from-to)1664-1673
Number of pages10
JournalLangmuir
Volume23
Issue number4
Early online date30 Dec 2006
DOIs
Publication statusPublished - 13 Feb 2007

Keywords

  • aggregation
  • polystyrene latex particles
  • stirred tank

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