Estimation of diffusion parameters in functionalized silicas with modulated porosity - Part I: Chromatographic studies
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Ημερομηνία
Συγγραφείς
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Elsevier
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Journal of Chromatography A
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
The diffusion parameters of binary gas mixture He (tracer gas)-N-2 (carrier gas) in hybrid organic-inorganic SiO2-X Porous solids which have suffered gradual functionalization with functional groups X of increasing length (X = theta, equivalent to Si-H, equivalent to Si-CH2OH, equivalent to Si-(CH2)(3)OH, equivalent to Si-(CH2)(11)CH3) are reported. The effective diffusivities D-eff, the Henry law constants K as well as the tortuosity factors tau for the examined solids were estimated by a typical pulse gas chromatographic method. Analysis of the experimental results was carried out by the well-known method of linearization of moments. The moments s analysis provides a powerful means for extracting diffusion parameters from the experimental response curves The proposed methodology is simple compared to other similar studies and provides rapidly reliable data. The results of this work indicate that the effective diffusivity D-eff in porous networks drops markedly as the initial porosity of the parent SiO2 sample is blocked by the functionalization of the pore surfaces with functional groups of increasing size, equivalent to Si-H, equivalent to Si-CH2OH, equivalent to Si-(CH2)(3)OH and equivalent to Si-(CH2)(11)CH3. The low values of the Henry law constants K found indicate that the adsorption of He on the porous surfaces for all the solids is weak. Also, the tortuosity factor tau is proportionally correlated to the pore blocking effects and the percolation phenomena of gases flowing into the porous network. (c) 2005 Elsevier B.V. All rights reserved.
Περιγραφή
Λέξεις-κλειδιά
effective diffusivity, tortuosity factors, henry constants, porous solids, functionalized silica, gas chromatography, zeolite crystal diffusivity, gas-chromatography, coefficients, catalyst
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://000229192500008
http://ac.els-cdn.com/S0021967305005820/1-s2.0-S0021967305005820-main.pdf?_tid=a56dcfd897b8737292906106b38566db&acdnat=1333035463_ff05200e1bf8b357520a0e5c443909c0
http://ac.els-cdn.com/S0021967305005820/1-s2.0-S0021967305005820-main.pdf?_tid=a56dcfd897b8737292906106b38566db&acdnat=1333035463_ff05200e1bf8b357520a0e5c443909c0
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας