Fabrication of Cellulose Acetate-Based Membrane Doped with Plasticizer for High-Efficiency Separation of CO2.

It is essential to develop a practical technology for the separation and capture of carbon dioxide (CO2) due to the gradually increased concentration of CO2 in the atmosphere, which has driven the rise in global temperature. Membrane separation is regarded as a promising technology for the capture of CO2. However, most membranes employ non-biodegradable petroleum-based polymers. In this study, biodegradable and renewable membranes of cellulose acetate (CA) doped with polyethylene glycol (PEG) and polyethylene glycol diacrylate (PEGDA) were fabricated by solution casting and used for the separation of CO2/O2. The results indicated that the membrane doped with PEGDA exhibited higher permeability of CO2 and selectivity of CO2/O2 compared to those doped with PEG, while improving the tensile strain and structural uniformity of membranes. The membrane with a thickness of 25 μm at a PEGDA dosage of 10 wt% achieved optimal gas permeability, selectivity, and mechanical toughness, showing CO2 permeability of 4.59 Barrer and CO2/O2 selectivity of 5.68. The structure of the interpenetrating polymer network was responsible for the excellent properties of the membrane doped with PEGDA due to the formation of more mid- and micro-sized pores that increase the diffusion pathways of CO2.