Abstract
The effects of ambient temperature (25A degrees C to 40A degrees C) and relative humidity (0% to 30%) on the adsorption of toluene, and 1,1,1 trichloroethane on silica alumina, silica alumina impregnated with KMnO4, and activated carbon granules and pellets were determined. VOC concentrations in the range 1-1000 ppm were studied. Measurements of the weight of the adsorbed VOCs as a function of time were made in a thermogravimetric analyzer (TGA). Linear isotherms were tested in all cases. Values of the Henry coefficient H were in the range 0.01-0.10 mm(3) air/mm(2) BET area; they decreased with both increasing temperature and relative humidity. The highest values of H were consistently observed with KMnO4-impregnated silica alumina. Empirical correlations relating H to the parameters employed in this study were derived. There was good agreement between the values of H calculated from equilibrium and kinetic data obtained in the TGA and corresponding values measured in a glass test chamber. Improved correlation of the data was obtained using the nonlinear Freundlich, Toth and Dubinin isotherms. The determined fitting parameters for toluene and 1,1,1-trichloroethane on activated carbon were in good agreement with data published in the literature.