Implementation of microfiltration in recycled usage of ionic liquid BmimCl and deep eutectic solvent ChCl/acetic acid for lignocellulosic biomass conversion

The recycled usage of ionic liquids (ILs) and deep eutectic solvents (DESs) is required for reducing the economic costs of the conversion of lignocellulosic biomass. In the study, implementation of membrane microfiltration in recycled usage of IL 1-butyl-3-methylimidazolium chloride (BmimCl) and DES choline chloride/acetic acid (ChCl/AA) for biomass conversion was considered. Aspen wood, pine wood, and sugarcane bagasse were used as representing hardwoods, softwoods, and grasses. BmimCl and ChCl/AA were collected after the biomass pretreatment and recycled 15 times through water evaporation. The pretreatment with the recycled 15 times BmimCl and ChCl/AA was characterized with 20–36% lower sugars yields compared to the fresh ones. After regeneration of BmimCl and ChCl/AA through membrane microfiltration, sugars yields reached 86–97% from the yields in the case of the fresh BmimCl and ChCl/AA. Membrane microfiltration was demonstrated to extend the opportunities for recycled usage of ILs and DESs for biomass conversion. [Display omitted] •Pretreatment with BmimCl provided higher sugars yield compared to ChCl/AA.•Recycled usage of BmimCl and ChCl/AA caused 20–36% decrease in sugars yield.•Decrease in sugars yield correlated with lignin accumulation in BmimCl and ChCl/AA.•BmimCl and ChCl/AA were regenerated through membrane microfiltration.•The filtration provided 86–97% restoration of sugars yield in biomass hydrolysis.