Comparison of first and second generation analytical silica monoliths by pore-scale simulations of eddy dispersion in the bulk region

Dzmitry Hlushkou, Kristof Hormann, Alexandra Höltzel, Siarhei Khirevich, Andreas Seidel-Morgenstern, Ulrich Tallarek*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

We present the first quantitative comparison of eddy dispersion in the bulk macropore (flow-through) space of 1st and 2nd generation analytical silica monoliths. Based on samples taken from the bulk region of Chromolith columns, segments of the bulk macropore space were physically reconstructed by confocal laser scanning microscopy to serve as models in pore-scale simulations of flow and dispersion. Our results cover details of the 3D velocity field, macroscopic Darcy permeability, transient and asymptotic dispersion behavior, and chromatographic band broadening, and thus correlate morphological, microscopic, and macroscopic properties. A complete set of parameters for the individual eddy dispersion contributions in the bulk was obtained from a Giddings analysis of the simulated plate height data. The identified short-range structural heterogeneities correspond to the average domain size of the respective monoliths. Our plate height curves show that structural improvements in the bulk morphology of 2nd generation monoliths play only a minor role for the observed improvement in overall column efficiency. The results also indicate a topological dissimilarity between 1st and 2nd generation analytical silica monoliths, which raises the question how the domain size of silica monoliths can be further decreased without compromising the structural homogeneity of the bed.

Original languageEnglish (US)
Pages (from-to)28-38
Number of pages11
JournalJournal of Chromatography A
Volume1303
DOIs
StatePublished - Aug 16 2013

Keywords

  • Direct numerical simulation
  • Domain size
  • Eddy dispersion
  • Morphological analysis
  • Radial heterogeneity
  • Silica monoliths

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

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