Resumo (PT):
Abstract (EN):
Composite carbon molecular sieve membranes (c-CMSM) were prepared in a single dipping–drying–carbonization
step from phenolic resin solutions (12.5–15 wt.%) loaded with boehmite nanoparticles (0.5–1.2 wt.%). A carbon matrix
with well-dispersed Al2O3 nanowires was formed from the decomposition of the resin and dehydroxylation of
boehmite. The effect of the carbon/Al2O3 ratio on the porous structure of the c-CMSM was accessed based on the pore
size distribution and gas permeation toward N2, O2, CO2, He, H2, C3H6 and C3H8. c-CMSM with higher carbon/Al2O3
ratios had a more open porous structure, exhibiting higher permeabilities and lower permselectivities. c-CMSM
performance was above the upper bound curves for polymeric membranes for several gas pairs, particularly for
C3H6/C3H8 (permeability toward C3H6 of 420 barrer and permselectivity of 18.1 for a c-CMSM with carbon/Al2O3 ratio
of 4.4).
Unsupported films were also prepared (carbon/Al2O3 ratio 7.3) and crushed into small flakes. Equilibrium isotherms
of H2, N2, O2, CO2, C3H8 and C3H6 at 293 K were determined on these flakes to obtain the kinetic and adsorption
selectivities toward gas pairs of interest; obtained adsorption and diffusion coefficients accurately predicted the
permeabilities of all studied gases except CO2 (experimental and predicted permeabilities of 1148 and 154 barrer,
respectively).
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
13