Resumen
Natural gas is predicted to be a potential energy source in the future. However, the presence of carbon dioxide in it causes corrosion of transportation pipeline and reduction of calorific value. Various separation technology such as adsorption, absorption, cryogenic distillation and membrane are commercialized for CO2/CH4 separation. However, the first three technology are energy intensive. As for membrane, its separation performance using polymeric membrane has reached a limit as depicted in the Robeson Upper Bound. Thus, a new type of membrane known as mixed matrix membrane (MMM) was researched to surpass the separation performance of polymeric membrane by incorporating inorganic fillers throughout it. In this work, a new MMM was developed by incorporating pristine and functionalized halloysite nanotubes (HNT) at different weight loadings throughout poly (2,6-dimethyl-1,4-phenylene oxide) (PPOdm) membrane via dry phase inversion technique. Functionalization of HNT (fHNT) was also carried out by grafting HNT with N-(2-Aminoethyl)-3-aminopropyl trimethoxysilane in hopes to resolve agglomeration and interfacial voids issue that commonly exist in MMM fabrication. Approximately 167% increase in CO2 permeability were attained by 1.0 wt% of fHNT whereas the CO2/CH4 selectivity was increased by 354% compared to pristine PPOdm membrane. The performance of PPOdm/fHNT was greater than pristine PPOdm and PPOdm/HNT presumably due to improvements in interfacial bonds between filler and polymer attributed by functionalization of HNT. Agglomeration was present upon incorporation of fillers at all weight loadings but other apparent defects such as voids were absent. Morphology of MMM remains dense and homogenous. At 1.0 wt% HNT loading, TGA and DSC also showed improved thermal stability, possibly due to increased loadings and better interfacial adhesion in which higher decomposition (Td = 451°C) and glass transition (Tg = 218°C) temperatures were reported.