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Abstract. Membrane based gas separation process technology has been recognized as one of the most efficient and advanced unit operation for gas separation. One of the problems in membrane gas separation is membrane performance. This paper explores the application of cellulose acetate (CA) membrane for natural gas purification and separation by improving its permeability and selectivity. The main interest in this research is to study the effect of quench medium on the gas separation performance towards its physical characteristics and gas separation performance of CA membrane. Cellulose acetate polymer was dissolved in nmethyl-2-pyrrolidone solvent and casted onto a glass plate using a pneumatically controlled casting system with fixed shear rate and solvent evaporation times. The parameter varied was the non-solvent used as quench medium during membrane post treatment that were methanol and n-hexane. The different quench media as post treatment affected the O 2 and N 2 gas permeation and O 2 /N 2 selectivity as well as the tensile strength of the flat sheet asymmetric membrane. Combination of methanol and n-hexane as quench media gave the best result than the other steps. This solvent exchange step influenced the morphology by producing thin skin layer and thus gives better gas separation performance than other steps

Membrane technology in gas separation application was commercialized approximately 30 years ago because of a number of advantages offered compare to the conventional technique. The use of poly (lactic acid) (PLA), a biodegradable polymer, as a membrane material would assist the reduction of depending to petroleum-based polymer. This study investigated the effect of evaporation time to the gas separation performance of PLA membrane. Membrane prepared from polymer solution consist of PLA and dicholoremethane (DCM) as solvent was fabricated using pneumatically controlled casting system with dry/wet phase inversion method. Permeation test was conducted using pure carbon dioxide and methane gas. The results revealed that as the evaporation time increased, the pore size and surface porosity decreased, while the skin layer thickness increased. Although the morphology of the prepared membranes showed the desirable structure, the gas separation performance of the membrane prepared with polymer concentration of 15wt% and 60s evaporation time was found to be promising but not yet commercially ready.