Effective separation, recovery and recycling of deep eutectic solvent after biomass fractionation with membrane-based methodology

Robust membrane-based methodology with ultrafiltration and electrodialysis was employed to separate and recovery the deep eutectic solvent constituents (formed with choline chloride-ChCl and ethylene glycol-EG) after biomass fractionation using hydrothermal and DES treatment. Ultrafiltration was designed for the profound removal of lignin in DES solution. Concentration of degradation products was less than 0.1 g/L when the resulting DES solution was diluted to 40 g/L of ChCl after ultrafiltration. Electrodialysis was proven effective to separate and recovery of ChCl and EG with ChCl transferred and EG retained. Recovery ratio of ChCl and EG approached 92% and 96% and purities reached 98-99% after electrodialysis treatment. Insight gained from this study suggests a green methodology for the recovery of DES constitutes after biomass fractionation as well as the foundation for large-scale DES-based bio-refineries.