CONICET | Buscador de Institutos y Recursos Humanos

NaA zeolite membranes were synthesized on top of both diskand tubular porous stainless steel substrates by the secondary growth method. The support seed stagewas optimized, considering the seed synthesis conditions and the depositionmethod. The formation of the NaA zeolite on both the membrane and the residualpowder collected at the bottom of the vessel after synthesis was corroboratedby X-ray diffraction (XRD). Scanning electron microscopy (SEM) revealed theformation of a film with well-defined crystals with a cubic morphology characteristicof the NaA zeolite. The support modification with 3-aminopropyltriethoxysilane improved themorphology and stability of the NaA zeolite membranes synthesized on top ofporous stainless steel substrates. When vacuum was applied only in the lasthydrothermal synthesis stage, a smooth zeolite layer was obtained on top ofporous stainless steel supports. The single gas (H2, N2,CO2 and CH4) and mixture (H2/N2 andH2/CH4) perm-selective properties of the tubular membraneswere evaluated as a function of temperature and pressure. Separation factorshigher than the Knudsen coefficient were obtained in all membranes. The singlegas H2 and CO2 permeation flux of the membranes increasedwith temperature indicating a preponderance of the activated diffusion over theKnudsen diffusion. The higher H2/CO2 ideal separationfactors were 7.6 and 5.6 for the more selective tubular membranes, at 453 K and100 kPa.