Methods | Extraction solvent | Catalyst | Washing procedure | Lignin precipitation | Ref. |
---|---|---|---|---|---|
Organosolv | Ethanol/water 50/50 by wt | 1% H2SO4 | Ethanol/water, 50/50 by wt then hot water | 10× volume of hot water | [15] |
Soda-AQ | 14 wt% active alkali in water | 0.1% AQ | Hot water | Adjusting pH to 2.0 | [23] |
Hydrotrope | 30 wt% sodium salicylate in water | 0.17% formic acid | Hot water | 10× volume of hot water | [26] |