Asymmetry of Hydrogen Transfer through a Composite Membrane

Abstract

Hydrogen mass transfer through a composite membrane represented by a film of palladium (or its alloys) applied onto a porous substrate has been studied. The hydrogen flux through the composite membrane has been shown to be governed by the ratio between the diffusion permeabilities of the film and the porous substrate, the mechanism of the transfer through the film, and the external pressure. It has been found that the intensity of hydrogen transfer through the composite membrane may depend on the transfer direction. The transfer is most asymmetric when the diffusion permeabilities of both layers are close and the hydrogen transfer in the film is limited by diffusion. At the same time, the transfer asymmetry effect does not arise when the hydrogen transfer in the film is limited by adsorption processes on its surface.