Measurements of diffusion coefficients in porous solids by inverse gas chromatography

The relatively new methodology of reversed-flow gas chromatography has been applied to measure the diffusion coefficients of gaseous species into porous solid material. The necessary experimental arrangements and the theoretical analysis were described, and the appropriate mathematical analysis which leads to equations describing the diffusion coefficients as a function of the experimental data and other measurable experimental conditions was developed. All of the calculations were performed using a simple software for a personal computer. The methodology was applied to pentane, hexane, and heptane diffusing into porous a- and γ-alumina as well as of sulfur dioxide diffusing into porous marble at various temperatures. The results were compared with those obtained by the Knudsen formula or those given by other researchers. © 2005, ASM International.