CO2/CH4 separation through a novel commercializable three-phase PEBA/PEG/NaX nanocomposite membrane

• Novel three-phase PEBAX/NaX/PEG mixed matrix membranes for CO2/CH4 separation.
• Comparison of CO2/CH4 separation before/after PEG and/or NaX introduction into PEBA.
• Enhanced CO2/CH4 separation performance using the synthesized PEBAX/NaX/PEG MMMs.
• Single gases permeability and selectivity versus pressure and PEG loading were measured.
• A commercializable three-phase MMM was introduced due to the Robeson's upper bound.

Three-phase polymer/liquid/solid (PEBA/PEG/nanozeolite X) mixed matrix membranes were synthesized. Effects of PEG and/or nanoparticle on CO2 and CH4 permeabilities and CO2/CH4 selectivity of the membranes were investigated. The synthesized membranes were characterized using AFM and SEM. CO2 Permeability and selectivity in the membranes increased with feed pressure and PEG loading. The PEBA membrane with loadings of 30% PEG and 10% nanozeolite showed the best performance; its CO2 permeability and CO2/CH4 selectivity at 8 bar were 95 Barrer and 45, respectively. Based on Robeson's upper bound, both the three-phase membranes of this work would be proper for being commercialized.

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