In this study, fumed silica nanoparticles were functionalized using amine groups and used as inorganic modifiers for preparation of poly (ether-block-amide) based nanocomposite membranes. Field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and CHNO elemental analysis were used to characterize nanoparticles and nanocomposite membranes. The prepared membranes were applied for separation of carbon dioxide (CO2) from methane (CH4). The effects of nanoparticles loading, feed pressure and feed temperature on permeability and CO2/CH4 ideal selectivity of the nanocomposite membranes were investigated. The results indicated that addition of 15 wt % of amine-functionalized fumed silica nanoparticles in the casting solution enhances the membrane CO2 permeability and CO2/CH4 ideal selectivity 10% and 14%, respectively. (C) 2017 Elsevier B.V. All rights reserved.