METAL-SUPPORTED CARBOGENIC MOLECULAR-SIEVE MEMBRANES - SYNTHESIS AND APPLICATIONS

Carbogenic molecular sieve membranes supported on macroporous sintered stainless steel flat plates have been synthesized by pyrolysis of a ( poly)furfuryl alcohol-acetone solution imbibed within the surface pore s of the support. Permeances of H-2, He, Ar, O-2, N-2, and SF6 were me asured to determine the permselectivity of these membranes. Experiment s performed on flat-plate membranes revealed molecular sieving behavio r with the permeance decreasing with increasing molecular size. Separa tion factors of 2-3 for O-2/N-2 and up to 30 for H-2/N-2 were obtained from single gas permeation experiments at 293 K. Higher temperature e xperiments demonstrated the activated nature of transport of various m olecules. A 1:1 O-2/N-2 mixture was partially separated over a range o f pressures at steady state. The lack of pressure dependence of the pe rmeances indicated that shape- and size-selective effects dominated th e separation. An EDAX analysis of the flat-plate surface reveals a def ect-free CMS layer.