Influence of glycol additives on the structure and performance of cellulose acetate/zinc oxide blend membranes

The effects of different types and concentration of glycol additives in the membrane blend formulations for pervaporation studies were investigated. The glycol additives used were polyethylene glycol 600 (PEG 600), propylene glycol (PG) and ethylene glycol (EG). Glycol additive filled cellulose acetate (CA)/zinc oxide (ZnO) blend membranes were prepared for pervaporation separation of isopropanol (IPA)/water mixtures. The structural morphology and thermal stability of the blended membranes were characterized by SEM, FTIR, DSC, and TGA. The mechanical properties were determined by using UTM. It was found that the presence of PEG 600 in the blend membrane enhanced the membrane pervaporation performance. The effect of the PEG 600 content in the blended membranes on the pervaporation was studied and discussed in terms of permeation flux and separation factor. The separation factor and permeation flux were increased by the addition of the PEG 600 content in the range of 7.5–10 wt.%. Among all the fabricated blended membranes, the membrane containing 10 wt.% PEG 600 showed the highest separation factor of 1448.03 and a permeation flux of 558.63 g/m2 h for a feed composed of 71 wt.% IPA in the aqueous solution at 40 °C.

Research Highlights
► The separation factor decreased with the increase in the additive content.
► The permeation flux increased with the increase in the additive content.
► The PEG/CA blend membrane showed high stability up to 305 °C.
► The addition of glycols additives in CA lowered the Tg of CA blend membranes.
► The additives improved the mechanical properties of membranes.