Cosorption of sulfur dioxide and water on cork

Abstract

The cosorption of gaseous sulfur dioxide (SO 2) and water vapor (H 2O) on raw cork powder by using calorimetry coupled with manometry at 298 K was studied. Sorption isotherms of single components confirm the previous results obtained by thermogravimetry: SO 2 is well chemisorbed on cork surface while H 2O is only physisorbed. Moreover, the interaction of SO 2 and H 2O with cork appears more like an absorption process than an adsorption process. Competitive sorption of SO 2 and H 2O first occurs in favor of SO 2 chemisorption. After all chemisorption sites are saturated by SO 2, the cosorption process becomes selective for H 2O. The amount of SO 2 sorbed on cork is rather low compared to H 2O. Results indicate that the sorption of SO 2 on cork cannot explain the decrease in SO 2 content observed during wine aging in bottle. © 2012 by the American Society for Enology and Viticulture. All rights reserved.