Rheological evaluation of the fabrication parameters of cellulose acetate butyrate membrane on CO2/N2 separation performance

The rise in emission of greenhouse gases (GHGs) mainly carbon dioxide (CO2) in recent years due to rapid development of modern civilisation, has been listed as the primary contributor to global warming. To address this global issue, membrane technology was applied and developed intensively because of its superior performance in terms of efficiency and economic advantages. In this study, the cellulose acetate butyrate (CAB) polymer was selected as the polymer matrix material since it exhibited excellent film-forming properties. In addition, the wet-phase inversion technique was adopted to synthesise the membrane based on different casting conditions. The optimum outcomes of the fabrication conditions were then characterised with the scanning electron micrograph (SEM) to determine the best CAB membrane for CO2/N2 separation. The results showed that CAB-70000 fabricated with 4 wt% of CAB polymer concentration, casting thickness of 250 µm, solvent evaporation time of 5 minutes, and 30 minutes of solvent exchange for isopropyl alcohol and n-hexane, exhibited the best gas separation performance. Further, CAB-70000 showed an average selectivity of 6.12 ± 0.09 and permeance up to 227.95 ± 0.39 GPU for CO2 and 37.28 ± 0.54 GPU for N2, respectively. In summary, this study is expected to show a detailed outline of the future direction and perspective of the novel CAB polymeric membrane that is suitable to be applied in the industry, and serves as an insight for researchers and manufacturers working in the related field of gas separation.