Removing carbon dioxide (CO₂) from natural gas is essential for improving fuel quality, preventing pipeline corrosion, and enhancing energy efficiency. Membrane technology offers a selective and efficient method for CO₂ removal, ensuring natural gas meets industry standards. This process reduces greenhouse gas emissions, supporting cleaner and more sustainable energy production. In this study, Mixed-matrix membranes (MMMs) incorporating graphene oxide (GO) stabilized by nanocellulose fibers (NCF) within a cellulose acetate (CA) matrix were synthesized and evaluated for CO₂/CH₄ gas separation. The CA/NCF/GO-1 membrane, with 1 wt% GO, demonstrated optimal performance, achieving a CO₂ permeability of 77.8 Barrer and an ideal CO₂/CH₄ selectivity of 24.3. SEM and FT-IR analyses confirmed the uniform dispersion of GO and strong filler-polymer interactions. XRD revealed enhanced crystallinity with GO addition, while TGA indicated thermal stability, with decomposition temperatures ranging from 277 °C to 310 °C. Mechanical testing showed increased tensile strength (up to 60 MPa) with filler addition, though excessive GO (2 wt%) caused aggregation and highly reduced % elongation at break. Gas permeabilities decreased at higher feed pressures (5 bar), aligning with the dual-sorption model. The CA/NCF/GO-1 membrane demonstrated high stability over one week and approached Robeson’s 2008 upper bound, highlighting its potential for industrial CO₂ separation.

Keywords: Mixed matrix membranes, Clean energy, Carbon dioxide separation, Graphene oxide.