Sorption and flow in graphite-zeolite compacts: I. Helium, argon and nitrogen

Abstract

Low porosity compacts of graphite and Linde Sieve zeolites NaA and CaA, 16) have been studied as diffusion and sorption media for helium, argon and nitrogen. The zeolite crystals in the compacts were outgassed and also hydrated in different series of experiments. There was evidence of surface fluxes and also of intracrystalline flows. On the assumption that helium has a negligible intracrystalline or surface flow, the surface and intracrystalline diffusion coefficients of nitrogen have been evaluated. The tortuosity of the conduction paths in the compacts is, however, high. The sorption isotherms of the three gases have been measured, and the Henry's law adsorption constants calculated and analysed in thermodynamic terms.