The influence of carbonization temperature on the permeation properties and aging of thin (4 mu m) supported carbon molecular sieve membranes (c-CMSM), prepared from in house synthesized novolac phenolic resin loaded with boehmite nanoparticles, were studied. Just after membrane carbonization (fresh membrane), high permeance to N-2 and O-2 and low O-2/N-2 permselectivities were observed; the highest permeations were observed for carbonization end temperatures between 500 degrees C and 700 degrees C. After leaving the c-CMSM 1 day in the air, a large decrease in the permeation and considerable increase in the permselectivity were observed due to the reduction of the pore size by oxygen chemisorption and water physical adsorption; the permeability to H-2 and H-2/N-2 ideal permselectivity for a membrane carbonized at 550 degrees C are close to palladium membranes for low temperature (<100 degrees C). The effect of the permeation characteristics of the membranes carbonized at various temperatures and the removal of water adsorbed in the pores by heat treatment were studied. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.