Sustainable recovery and recycling of natural deep eutectic solvent for biomass fractionation via industrial membrane-based technique.

Natural deep eutectic solvents (NADES) have been proven efficient and biocompatible as solvents and conversion medium in many fields. Multicomponent composition makes it hard to direct recovery NADES after utilization process. Industrial application of NADES requires sustainable and economic recovery technology. In this study, hybrid membrane-based technique of ultrafiltration (UF) with bipolar membrane electrodialysis (BMED) was employed for sustainable recovery and recycling of NADES choline chloride-urea in pine wood fractionation. UF and BMED worked based on retaining of macromolecules and distinguished separation of each NADES solute. The highest NADES recovery ratio was 97.7 % and the lowest specific energy consumption for NADES recovery was 8.4 kWh/kg. Regenerated NADES was recycled in biomass fractionation for 3 batches. Removal efficiency of hemicellulose (∼25.4 %) and lignin (∼18.1 %) could be retained with regenerated NADES. Besides, NADES recovery cost by UF-BMED was close to 3.0 % of its purchasing price according to calculation results. Insight gained from the research proposed a sustainable and low-cost technique for NADES recycling in biomass utilization. [Display omitted] • Hybrid membrane strategy designed for NADES recovery. • NADES recovery ratio close to 97.7 %. • Specific energy consumption of NADES recovery approached 8.4 kW·h/kg. • NADES recovery cost verge on 3.0 % of its purchase price. [ABSTRACT FROM AUTHOR]