SIMPLE AND GREEN PRODUCTION OF LIGNIN NANOPARTICLES USING ETHANOL-WATER MIXTURES AND ULTRASONICATION

Lignin nanoparticles (LNPs) have emerged as promising bio-based materials for sustainable applications, but conventional synthesis methods often rely on surfactants, chemical modifications, or toxic solvents. In this study, we present a simple and environmentally friendly approach for producing LNPs using ethanol-water mixtures and ultrasonication, without the use of additives or hazardous reagents. Two solvent compositions (70 and 90% ethanol, v/v in water) and varying sonication times (0-2 h) were evaluated to investigate their effects on nanoparticle formation, morphology, and size. Visual assessment and scanning electron microscopy (SEM) revealed that 70% ethanol promotes spontaneous nanoparticle formation with spherical morphology and good dispersion, even without sonication. In contrast, 90% ethanol required prolonged ultrasonication to produce smaller and more uniform particles. Particle size analysis confirmed that ultrasonication enhances particle refinement, especially in the solvent systems with higher ethanol content. This minimalist, surfactant-free method demonstrates the potential for scalable and green production of lignin nanoparticles, offering a valuable platform for future development of functional bio-based nanomaterials.