NaA zeolite membranes synthesized on top of APTES-modified porous stainless steel substrates

YOHANA MARTÍNEZ GALEANO, LAURA CORNAGLIA, ANA M. TARDITI

JOURNAL OF MEMBRANE SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 512 p. 93 - 103

0376-7388

NaAzeolite membranes were synthesized on top of both disk and tubular porousstainless steel substrates by the secondary growth method. The support seed stage was optimized,considering the seed synthesis conditions and the deposition method. The formationof the NaA zeolite on both the membrane and the residual powder collected atthe bottom of the vessel after synthesis was corroborated by X-ray diffraction(XRD). Scanning electron microscopy (SEM) revealed the formation of a film withwell-defined crystals with a cubic morphology characteristic of the NaAzeolite. The support modification with 3-aminopropyltriethoxysilane improved the morphology and stability of the NaA zeolite membranessynthesized on top of porous stainless steel substrates. When vacuum wasapplied only in the last hydrothermal synthesis stage, a smooth zeolite layerwas obtained on top of porous stainless steel supports. The single gas (H2,N2, CO2 and CH4) and mixture (H2/N2and H2/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.