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Adsorption equilibria of α- and δ-tocopherol from supercritical mixtures of carbon dioxide and 2-propanol onto silica by means of perturbation chromatography
Publikationstyp
Journal Article
Date Issued
2007-02-13
Sprache
English
Author(s)
Institut
TORE-URI
Volume
42
Issue
2
Start Page
180
End Page
188
Citation
The Journal of Supercritical Fluids 2 (42): 180-188 (2007)
Publisher DOI
Scopus ID
Publisher
Science Direct
For the determination of adsorption isotherms of dissolved components from supercritical fluids, an experimental equipment has been constructed. It consists of a fluid preparation and two chromatographic units with UV detector and pressure expansion. The equipment allows the performance of peak experiments (injecting samples onto an empty column) as well as perturbation experiments (perturbing the equilibrium in a saturated column). Adsorption isotherms of α- and δ-tocopherol on two unmodified silica gels were determined at a temperature of 313.15 K and pressures of 16.1, 20.0, and 26.1 MPa, respectively. Fluid phase was CO2 with 2-propanol (weight fraction 0.05) as modifier. Parameters of a cubic Hill isotherm were fitted to the data. Ideal adsorbed solution theory (IAST) was applied for prediction of mixture adsorption. Applicability of IAST was tested with perturbation chromatographic experiments using different mixtures. All isotherms show anti-Langmuir behaviour (concave shaped isotherms). These results agree with literature data. Competitive adsorption was successfully predicted by means of the IAS theory.
Subjects
adsorption isotherm
carbon dioxide
IAS theory
phase equilibrium
silica gel
tocopherol
DDC Class
500: Naturwissenschaften
530: Physik
More Funding Information
German Research Foundation (DFG)
Grant Jo 339/1
Grant Jo 339/1