The separation of carbon dioxide from CO2/N-2 gas mixture using membrane-absorption technology has been investigated. Poly(vinylidene fluoride) (PVDF) membrane was prepared using phase inversion method with N, N-Dimethylacetamide (DMAc) as the solvent and monoethanolamine (20 wt%) was used as the carbon dioxide absorbent. The hydrophobic silica nanoparticles modified with vinyl groups used to raise the hydrophobic character of the prepared polymeric membranes. The chemical structure and hydrophobicity of the silica nanoparticles was studied. The mixed matrix membranes morphology, hydrophobicity, thermal and mechanical properties were investigated. The results showed that the nanoparticles were properly modified with vinyl groups and their contact angles increased from 34 to 131. Low amount addition of nanoparticles to the polymeric solution caused macrovoid formation, while increasing the nanoparticles loading suppressed macrovoid formation. Carbon dioxide absorption efficiency has been increased by increasing loading of nanoparticles into the membrane because of its smaller pore size and higher hydrophobicity. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.