Mixed matrix membranes were prepared from derivatized polysulfone and zeolite particles. Aminopropyltrimethoxysilane was used as coupling agent to covalently link zeolite particles with the acrylate modified polymer. The mixed gas selectivity for H(2)/CO(2) separation increased from 1.53 for pure polysulfone to 3.57 at 40% zeolite loading. The results suggest that the covalent linkage of polymer and filler results in defect free membranes. The effect of different operating conditions (feed pressure, temperature and CO(2) feed concentration) was also studied. (C) 2010 Elsevier B.V. All rights reserved.