Sustainable extraction and physicochemical characterization of nano-lignin derived from jute-based agro-industrial biomass

The aim of this research was to extract lignin from jute-based agro-industrial biomass and synthesize nano-lignin particles using a sustainable solvent-anti-solvent precipitation process, followed by the physicochemical characterization of the synthesized particles. Different characterization techniques such as FTIR, SEM, EDX, DLS, XRD, Zeta Potential, TGA and DSC were carried out to evaluate the structural and physicochemical characteristics of the synthesized nano-lignin particles. FTIR analysis showed the presence of important lignin functional groups such as hydroxyl (3316 cm ^-1 ), carbonyl (1650 cm ^-1 ), aromatic groups (1419 cm ^-1 ) and C-O groups and similar characteristic peaks were observed after nano-lignin synthesis. SEM analysis revealed irregular, porous, fragmented and heterogeneous surface morphology of the synthesized particles, which is consistent with the commonly reported characteristics of nano-lignin particles. DLS analysis showed an average particle size of around 117 nm, with uniform particle size distribution. The zeta potential value was found around -35 mV (millivolt), suggesting comparatively good colloidal stability and dispersion behavior of the synthesized nano-lignin particles. XRD analysis indicated, predominantly amorphous structural characteristics, which are consistent with the traditionally reported amorphous characteristics of lignin-based nanoparticles. EDX analysis showed that carbon and oxygen were dominant detected elements in the synthesized samples. TGA and DSC analyses suggested that the synthesized nano-lignin particles exhibited multi-stage thermal degradation behavior. Overall, this research reported a sustainable approach for lignin extraction and nano-lignin synthesis from jute-based agro-industrial biomass. Further studies may be carried out to investigate the synthesized nano-lignin particles through more detailed and advanced characterization techniques.