Thermodynamics and Kinetics Study of the Adsorption and Diffusion of p-Xylene in Silicalite-1.

Gravimetric equilibrium isotherms, thermodynamic parameters, and diffusion of p-xylene in silicalite-1 were investigated at several temperatures using an intelligent gravimetric analyzer (IGA). Both plateau and hysteresis loops appeared in the isotherms obtained at 323 and 343 K, respectively. Heat of sorption ( Q_st), free energy change (Δ G), entropy change (Δ S), and entropy ( S_a) of the adsorbed phase at various sorption coverages were determined from the adsorption isotherms. The diffusion coefficients at different loadings were also calculated using Fick's equation. The calculated thermodynamic and kinetic parameters satisfactorily explain the adsorption process and isotherm features. [ABSTRACT FROM AUTHOR]