Interests on the gas separation using ceramic membranes have considerably increased for gas separation potentials since they have a high as permeance and represent better thermal, chemical and mechanical stabilities than polymeric membranes. The influence of adsorption on the permeation properties of gas species having different adsorption capacity was investigated in the mesoporous gamma-alumina ceramic membrane. It was observed that the adsorption of the adsorbing gas species in the single gas systems increased permeance than the value predicted by the Knudsen diffusion. thus, decreasing the resistance for gas transport through the membrane. In the permeation results for the binary mixture gas systems, the preferential adsorption on the pores increased permeation performances of the adsorbing gas species. It is considered that the adsorption of the adsorbing gas species increased the permeation performances by limiting the diffusion of the weakly adsorbing gas species through the mesoporous membrane. (c) 2005 Elsevier B.V. All rights reserved.