• Madeira, Lm
• Llosa Tanco, Mal
• Sousa, Jm
• Pacheco Tanaka, Dap
• Teixeira, M.
• Rodrigues, Sc
• Campo, M.
• Mendes, A.

Abstract

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/Al(2)O(3)ratio on the porous structure of the c-CMSM was accessed based on the pore size distribution and gas permeation toward N-2, O-2, CO2, He, H-2, 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/Al(2)O(3)ratio 7.3) and crushed into small flakes. Equilibrium isotherms of H-2, N-2, O-2, 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).

Topics

• nanoparticle
• porous
• pore
• Carbon
• composite
• permeability
• resin
• decomposition
• drying