The influence of cellulose acetate butyrate membrane structure on the improvement of CO₂/N₂ separation

Abstract

Global warming has been identified as a serious environmental issue. The most promising way to stop the greenhouse gas effect is to develop a high-performance membrane for CO₂ separation. In this study, research was conducted to determine the effects of different polymer concentrations (2 wt%, 4 wt%, and 6 wt%) and casting thicknesses (150 µm, 250 µm, and 300 µm) on the membrane performance. The obtained results showed cellulose acetate butyrate (CAB) membrane with polymer concentration of 4 wt% and casting thickness of 250 μm had a CO₂/N₂ selectivity of 1.398 ± 0.03. Thus, the mixed matrix membrane (MMM) was developed with 4 wt% of CAB polymer and 0.1 wt% functionalized multi-walled carbon nanotubes. Hence, this study confirmed that MMMs result in a better performance than polymeric membranes where the CO₂ permeance, N₂ permeance and CO₂/N₂ selectivity of the MMM were 365.741 ± 0.667 GPU, 73.410 ± 0.741 GPU, and 4.980 ± 0.050, respectively.

Keywords:

• Casting thickness
• cellulose acetate butyrate
• gas separation
• mixed matrix membrane
• multi-walled carbon nanotubes
• polymer concentration

Additional information

Funding

The authors would like to offer their appreciation to the Ministry of Higher Education Malaysia (MOHE) for approving Fundamental Research Grant Scheme (FRGS) (MOHE Ref No: FRGS/1/2015/TK02/CURTIN/03/01) and Cost Centre: 001048. We would also like to thank LRGS USM (Account No: 304/PJKIMIA/6050296/U124) and Curtin Cost Centre: 001047.