Organic solvent reverse osmosis (OSRO) for the recovery of hemicellulosic derivatives after wood-pulping with a deep eutectic solvent

Abstract

This work investigates the recovery of a deep eutectic solvent (DES) used for pulping wood, by removing remnant hemicellulosic derivatives using reverse osmosis (RO). Xylose and its dehydration product furfural are considered representative hemicellulosic derivatives, and a lactic acid-choline chloride DES was used. Various diluting solvents were considered for the RO feed, namely pure water and binary water-organic solvent (ethanol, acetone, and methanol) mixtures. The results in this work show that the xylose rejection is high in water as well as in the presence of organic solvents such as acetone (with 97% rejection in aqueous acetone solvent and 95% in pure water using the RO membrane). On the other hand, furfural is rejected poorly by the RO membrane in all media (below 60% in all solvents). Finally, based on these results, a separation scheme was proposed to attain a complete mass recovery of each component of this mixture.