Permeation time lag analysis of “anomalous” diffusion. Part 1 .—Some considerations on experimental method

Abstract

A previously proposed scheme for investigating “anomalous” diffusion is applied to a system composed of an ideal, moderately adsorbed gas (N₂) in a microporous compact. The thorough application of this method required measurement of four time-lags on each of two opposite flow directions along a single diffusion axis. Certain procedures were also developed in order to correct for inevitable departures from the theoretical boundary conditions in permeation experiments. These necessitated measurement of absorption and desorption kinetics. The corrected data exhibit a satisfactory agreement between the overall time-lag quantity δΔL and its theoretical value deduced from steady-state and equilibrium parameters.