Recovery of Monoethanolammonium Acetate from Ionosolv Liquors Using a γ-Valerolactone-Based Aqueous Two-Phase System
Sara Villarino1, Victoria Rigual1, Francisco Rodríguez1
1Department of Chemical and Materials Engineering, Complutense University of Madrid, Madrid, Spain.
Chemsuschem
|June 17, 2026
Summary
This study introduces a novel, energy-saving method for recovering lignin using a gamma-valerolactone (GVL)-based aqueous two-phase system (ATPS). This approach significantly reduces energy demand for solvent regeneration in lignin extraction processes.
Area of Science:
- Biomass valorization
- Green chemistry
- Separation science
Background:
- Ionic liquids (ILs) are effective for lignin extraction in the Ionosolv process.
- Sustainable IL implementation necessitates efficient lignin recovery and IL recycling.
- Conventional water-based lignin precipitation is energy-intensive due to water's high enthalpy of vaporization.
Purpose of the Study:
- To develop a more energy-efficient lignin recovery strategy using gamma-valerolactone (GVL)-based aqueous two-phase systems (ATPS).
- To investigate the phase behavior of a water + GVL + monoethanolammonium acetate ([MEA][OAc]) ATPS.
- To evaluate the effectiveness of GVL-based ATPS for lignin recovery from Ionosolv liquors and assess the quality of the recovered lignin.
Main Methods:
- Experimental determination and thermodynamic modeling (NRTL) of the ternary ATPS phase behavior.
- Lignin extraction from Eucalyptus wood using the IL [MEA][OAc].
- Application of the GVL-based ATPS to Ionosolv liquor for selective lignin partitioning.
- Lignin isolation using low-enthalpy organic anti-solvents.
- Structural characterization of precipitated lignin using 2D-NMR.
Main Results:
- The GVL-based ATPS enabled selective partitioning of lignin into the GVL-rich phase.
- Lignin was successfully isolated using various organic anti-solvents.
- Recovered lignin exhibited high syringyl content and low recondensation, indicating enhanced depolymerizability.
- The proposed method reduces solvent-regeneration energy demand by up to 44% compared to water precipitation.
- Favorable structural features of lignin were preserved.
Conclusions:
- GVL-based ATPSs offer a promising, lower-energy downstream processing option for lignin recovery from Ionosolv liquors.
- This strategy enhances the sustainability of IL-based lignin extraction by enabling efficient IL recycling.
- The recovered lignin retains desirable structural characteristics for further valorization.
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