Influence of the Pore Diameter on the Adsorption Behaviour of Nonpolar Molecules on SiO-Adsorbents

Abstract

The adsorption equilibrium of n -paraffins (ethane, n -butane, n -hexane and n -decane) and some noble gases on SiO 2 -adsorbents with different pore diameter have been investigated using the techniques of isostere-, isotherm- and calorimetric-measurements. There is a strong influence of the pore diameter on the adsorption potential. As the pore diameter of the adsorbents increases the adsorption enthalpy decreases while the adsorption entropy increases. For the initial heats of adsorption of the n -alkanes an empirical equation is derived, allowing the calculation of the thermodynamic data in advance, knowing the (mean) pore diameter.