Desorption isotherms for water, ethanol, ethyl acetate and toluene from a sodium smectite clay have been determined by both dynamic vapor sorption (DVS) measurements and Knudsen thermogravimetry (KTGA), at the exception of toluene that was measured only by the DVS method. The results obtained using these two methods were in satisfactory agreement, providing reliable insight into the desorption process, with certain lack of precision for ethyl acetate. The observed desorption behaviour suggests a liquid like phase at high volatile load, and a sorbed state in which molecules interact with the counter ions, at low volatile contents. However, the isotherms for water determined at various temperatures nearly superposed when plotted as a function of water activity, indicating the strength of the interactions in the clay-water system to remain of the same order of magnitude as that in bulk water, consistent with previous ab initio calculations.

Equilibrium desorption isotherms of water, ethanol, ethyl acetate, and toluene on a sodium smectite clay / P. Clausen, M. Signorelli, A. Schreiber, E. Hughes, C. J. G. Plummer, D. Fessas, A. Schiraldi, J.A.E. Månson. - In: JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY. - ISSN 1388-6150. - 98:3(2009), pp. 833-841.

Equilibrium desorption isotherms of water, ethanol, ethyl acetate, and toluene on a sodium smectite clay

M. Signorelli
Secondo
;
D. Fessas;A. Schiraldi
Penultimo
;
2009

Abstract

Desorption isotherms for water, ethanol, ethyl acetate and toluene from a sodium smectite clay have been determined by both dynamic vapor sorption (DVS) measurements and Knudsen thermogravimetry (KTGA), at the exception of toluene that was measured only by the DVS method. The results obtained using these two methods were in satisfactory agreement, providing reliable insight into the desorption process, with certain lack of precision for ethyl acetate. The observed desorption behaviour suggests a liquid like phase at high volatile load, and a sorbed state in which molecules interact with the counter ions, at low volatile contents. However, the isotherms for water determined at various temperatures nearly superposed when plotted as a function of water activity, indicating the strength of the interactions in the clay-water system to remain of the same order of magnitude as that in bulk water, consistent with previous ab initio calculations.
Clay; Dynamic vapour sorption; Ethanol; Ethyl acetate; Knudsen thermogravimetry; Smectite; Sorption isotherm; Toluene; Water
Settore CHIM/02 - Chimica Fisica
2009
http://www.springerlink.com/content/236252v562088g83/
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/67337
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