To cite this article: Sugu, L. & Jawad, Z. A. (2019). Formation of low acetyl content cellulose acetate membrane for CO₂/N₂ separation. J. Phys. Sci., 30(1), 111–125, https://doi.org/10.21315/jps2019.30.1.9

ABSTRACT

The rising carbon dioxide (CO₂) emissions over the decades is known to be a huge contributor to the greenhouse effect. CO₂ capture and storage methods have been perceived as favourable solutions to prevent global warming and climate change rising from the greenhouse effect. One energy efficient technology for separating CO₂ is the development of high-performing CO₂ gas separating membranes. A variety of membrane-based gas separation technologies designed have shown promising results and are inexpensive. A high-performing membrane must have a defect-free, thin dense skin-layer with a porous sub-layer for support that permits great permeation rate and selectivity. Of all ranges of polymers used to make polymeric membranes for CO₂/nitrogen (N₂) separation, cellulose acetate (CA) polymer membranes are known for their high CO₂ solubility. In this research, the effect of CA polymer concentrations at low acetyl group of 39.8% and casting thickness on the structure and morphologies of the membranes were studied. The CA polymer concentration was optimised from a range of 10 wt%, 15 wt% and 20 wt%, and the casting thickness was optimised from a range of 150 μm to 400 μm using wet-phase inversion technique. The results obtained exhibit a CA membrane with thin dense, selective skin-layer achieved at CA polymer concentration of 15 wt% and a casting thickness of 300 μm, with a CO₂ permeance rate of 401.173 ± 0.579 (GPU), N₂ permeance rate of 133.499 ± 0.148 (GPU) and selectivity of 3.009 ± 0.00656. This CA membrane is able to contribute to promising gas separation performances with enhanced physical and mechanical support by improvement of membrane permeance and selectivity towards CO₂/N₂ separation performance.

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