Adsorption equilibrium and kinetics for capillary condensation of trichloroethylene on MCM-41 and MCM-48

Adsorption equilibrium data of trichloroethylene (TCE) on synthesized MCM-48 were determined at different temperatures (303.15, 308.15, 313.15, 323.15 K) using a gravimetric technique. MCM-41 was chosen for comparison purpose. The adsorption equilibria of TCE on two mesoporous materials show an unusual type IV isotherm. A hybrid isotherm model composed of Langmuir and Sips equations was applied to fit TCE adsorption on mesorpores including its surface adsorption and capillary condensation. The proposed isotherm correlated the measured adsorption data quite well over the whole pressure range. Adsorption kinetics for MCM-41 and MCM-48 was also investigated under two distinct pressure regions representing surface adsorption and capillary condensation, using a diffusion model. It was found that the mass transfer for the region of capillary condensation was considerably slower than that for the surface adsorption region. We also found that the mass transfer in MCM-48 having the cubic mesopore system was faster than that in MCM-41 having the cylindrical mesopore structure. (C) 2004 Elsevier Inc. All rights reserved.