Lignin Nanoparticles Produced from Wheat Straw Black Liquor Using γ-Valerolactone

Area of Science:

• Materials Science
• Green Chemistry
• Biotechnology

Background:

• Black liquor from wheat straw pulping presents a silica challenge for sustainable valorization.
• Lignin, a major component of black liquor, is an underutilized biomass resource.
• Efficient recovery and modification of lignin are crucial for biorefinery development.

Purpose of the Study:

• To develop a method for producing stable lignin nanoparticles (LNPs) from wheat straw black liquor.
• To address the silica problem hindering black liquor recovery.
• To explore the potential of LNPs for advanced material applications.

Main Methods:

• Nanoprecipitation technology using gamma-valerolactone (GVL) as a solvent and water as an anti-solvent.
• Characterization of LNPs using particle size analysis and Zeta potential measurements.
• Analysis of lignin structure and properties using 2D-HSQC NMR, FTIR, TGA, and 31P-NMR.

Main Results:

• Uniform, well-dispersed, and stable lignin nanoparticles (LNPs) were successfully produced.
• Optimal conditions yielded LNPs with a particle size of 161 nm and Zeta potential of -24 mV at 87% GVL concentration.
• Lignin's chemical structure and bonding were preserved, with enhanced thermal stability.
• Abundant phenolic hydroxyl groups were quantified, indicating potential for further modification.

Conclusions:

• Nanoprecipitation offers an effective route for wheat straw black liquor valorization.
• The produced LNPs are stable and retain desirable lignin properties.
• This study opens new avenues for utilizing lignin-derived nanomaterials in various applications.