Performance tuning of chitosan-based membranes by protonated 2-Pyrrolidone-5-carboxylic acid-sulfolane DES for effective water/ethanol separation by pervaporation

Today, the applicability of deep eutectic solvents (DES) in various fields, including mem-brane science and technology, is extensively investigated. In pioneering works, we have implemented different DES as a component of chitosan (CS)-based flat membranes for pervaporation (PV) separation. Herein, we present a new protonated (by sulphuric acid) 2-Pyrrolidone-5-carboxylic acid: sulfolane DES, as a green additive for its chemical blending and thus study its effect in CS structure. The resultant flat CS-based membranes have been characterized and tested for their ability in separating water molecules from etha-nolic mixtures (10 wt% water in ethanol) using PV. Experiments revealed a progressive increase in total permeation along with increase of temperature in the range of 20-50 degrees C. Simultaneously, the value of separation factor was reduced. The maximum permeation (approximately 0.44 kg m-2 h-1) was observed for the highest experimental temperature, in which water was the main component, while the highest separation factor (approxi-mately 518) was observed for lowest operating temperature. It was confirmed that ap-plication of selected DES allowed to improve the permeation rates in comparison with the bare CS membrane. As a perspective, such membranes could be tested for another hy-drophilic pervaporation applications for the removal of polar compounds - with high applicability in biorefineries.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.