High performance mixed matrix membranes arise from a targeted selection of constituent materials, especially the choice of fillers. An amine-functionalizecl metal-organic framework (MOP), NH2-MIL-125 (Ti), was used in this work to prepare polysullone-based mixed matrix membranes (MMMs). Permeation measurements on CO2/CH4 gas mixture demonstrate that the incorporation of NH2-MIL-125(Ti) particles can significantly improve the CO2 permeability compared to the pure polymer membrane, along with slightly enhanced CO2/CH4 separation factor. This work also shows that the separation factor at high pressures can remain almost unchanged for the prepared MMMs with the MOF loadings up to 20 wt%. The obtained results may provide useful information in facilitating the applications of promising MOFcontaining MMMs for the practical membrane-based natural gas purification. (C) 2015 Elsevier B.V. All rights reserved.