Preparation of carbon molecular sieves by propylene pyrolysis over microporous carbons

Modification of the pore structure of microporous carbons by depositing carbons from pyrolysis of C3H6 between 973-1123 K was investigated in regard to development of molecular sieving properties for separation of O2 and Ar. Excellent adsorption kinetics and selectivity for separation of O2 and Ar were achieved by depositing carbon on a substrate carbon that contains pores of a narrow size distribution. Activated carbons showed no useful development of molecular sieving characteristics after carbon deposition. This is attributed, primarily, to their containing too wide a size distribution of micropores.