A novel method for woody biomass separation with the mixture of aqueous ethanol and ionic liquid

The mixture of aqueous ethanol and ionic liquid (IL) 1-butyl-3-methylimidazolium bromine ([Bmin]Br) was used to treat woody biomass, and different analysis methods such as ¹H-NMR, GC-MS, HPAEC, and FTIR were used to determine the efficiency of separation and the products. It is shown that macromolecules of lignin were degraded and dissolved into the solvent mixture, and were separated by adding anti-solvent into the solution. The presence of ionic liquid enhanced the hydrogen bonding capacity of the solvent, and hindered the adsorbing of lignin micro-molecules by cellulose, which resulted in the cellulose being separated as solid residue with high purity (≥94%). Therefore, the mixture of aqueous ethanol and IL offers a novel method for wood separation.