C[O.sub.2]-Philic [EMIM][[Tf.sub.2]N] Modified Silica in Mixed Matrix Membrane for High Performance C[O.sub.2]/C[H.sub.4] Separation

Separation of carbon dioxide (C[O.sub.2]) from methane (C[H.sub.4]) using polymeric membranes is limited by trade-off between permeability and selectivity as depicted in Robeson curve. To overcome this challenge, this study develops membranes by incorporating silica particles (Si) modified with [EMIM][[Tf.sub.2]N] ionic liquid (IL) at different IL:Si ratio to achieve desirable membrane properties and gas separation performance. Results show that the IL:Si particle has been successfully prepared, indicated by the presence of fluorine and nitrogen elements, as observed via Fourier-Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectrometer (XPS). Incorporation of the modified particles into membrane has given prominent effects on morphology and polymer chain flexibility. The mixed matrix membrane (MMM) cross-section morphology turns rougher in the presence of IL:Si during fracture due to higher loadings of silica particles and IL. Furthermore, the MMM becomes more flexible with IL presence due to IL-induced plasticization, independent of IL:Si ratio. The MMM with low IL content possesses C[O.sub.2] permeance of 34.60 [+ or -] 0.26 GPU with C[O.sub.2]/C[H.sub.4] selectivity of 85.10, which is far superior to a pure polycarbonate (PC) and PC-Sil membranes at 2 bar, which surpasses the Robeson Upper Bound. This higher C[O.sub.2] selectivity is due to the presences of C[O.sub.2]-philic IL within the MMM system.