CO2 separation from N-2 over 3-aminopropyltrimethoxysilane-grafted mesoporous SAPO-34, which had been synthesized using an amphiphilic organosilane additive was investigated. The presence of mesopores with a mean pore diameter of similar to 3.3 nm was confirmed by the characteristic small angle X-ray diffraction peak at ca. 1.3 degrees, transmission electron microscopy, and N-2 adsorption isotherm. The CO2 adsorption isotherms of the SAPO-34 samples were obtained at 273, 298 and 303 K, and the heat of adsorption was estimated using the Clausius-Clapeyron equation. The amine-functionalized mesoporous SAPO-34 showed a significantly improved CO2/N-2 selectivity of 177 and a sharp breakthrough in the fixed bed adsorption. CO2 adsorption-desorption of the sample was stable and reproducible during five cyclic runs. (C) 2012 Elsevier Ltd. All rights reserved.