Study of hydrogen transport through porous aluminum and composite membranes

Porous aluminum membrane has been prepared by annealing, quenching and acid etching a commercial Al foil. Hydrogen and carbon dioxide permeation and separation properties have been measured under pressure gradient. H 2 and CO 2 permeability coefficients for porous Al membrane have been found to increase with increasing etching time, whereas H 2 / CO 2 selectivity first increases then decreases. In order to improve H 2 / CO 2 selectivity, composite membrane has been prepared by depositing a thin layer ( ∼ 8 μ m ) of polysulfone (PSF) on the highly porous Al membrane. The optical micrographs show that microstructures of Al grain particles and openings of etch pits are of micron order.