The Kinetics of Adsorption of Water from Aqueous Ethanol Using 3A Molecular Sieves

Abstract

Adsorption onto molecular sieves has been studied as a means of concentrating aqueous ethanol, especially at compositions above 80 wt % ethanol. Some authors have investigated the effects of such variables as particle size and solid-fluid superficial velocity on the rate of sorption; however, little has been said about temperature influence. The present work describes both the experimental facilities designed, as well as procedures performed in order to evaluate the effect of temperature and other variables on the kinetics of sorption. Based on the Finite Bath approach, an experimental cell was used, which promoted continuous circulation of the fluid phase over a fixed bed of adsorbent. Equilibrium and kinetic experimental data were obtained at 25, 40 and 60°C. Above room temperature, a different transport mechanism operates, which apparently involves co-adsorption of ethanol and probably indicates difference in mobility between water and ethanol molecules.