Volterra integral equations for the determination of diffusion coefficients in fast pressure-jump sorption kinetics experiments

Abstract

Recently, the single-step frequency-response method has been proposed as a new experimental technique for the detection of fast adsorption/desorption kinetics of gases on porous solids. In this technique, a microporous sorbent is subjected to a jump-like pressure change brought about by a very rapid volume compression/expansion. By recording the gas pressure in the sorption system, sorption uptake/desorption kinetics can be followed. Volterra integral equations are shown to be a very useful tool for the treatment of the data obtained by this new type of diffusion experiment. The theoretically predicted features of the pressure vs. time curves are verified by a sorption uptake experiment of n-butane on silicalite.