Mixed matrix membranes incorporated with amine-functionalized titanium-based metal-organic framework for CO2/CH4 separation

• Preparation of new mixed matrix membranes (MMMs) based on PSF and NH2-MIL-125(Ti).
• Simultaneously enhanced gas permeability and separation factor with adding the MOF.
• The MMMs can maintain the performance at high pressure for CO2/CH4 separation.

High performance mixed matrix membranes arise from a targeted selection of constituent materials, especially the choice of fillers. An amine-functionalized metal-organic framework (MOF), NH2-MIL-125(Ti), was used in this work to prepare polysulfone-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 MOF-containing MMMs for the practical membrane-based natural gas purification.