Novel ternary based natural deep eutectic solvents (NADES) for sustainable extraction of lignin nanoparticles from waste Pinus roxburghii needles: A green approach

In the present work, a new series of ternary-based natural deep eutectic solvents (NADES) were prepared and tested for the effective extraction of lignin nanoparticles from pine needles (Pinus roxburghii). The performance of various NADES in terms of extraction and selectivity was assessed by optimizing the various parameters such as processing time, temperature, and pine needles: NADES ratio by weight for improved lignin yield. Among the various ternary NADES, Lac:Oxa:ChCl (LOC) in a molar ratio 4:1:1 proved to be the best, resulting in the extraction of 95.8 % of total lignin present with a purity of 93.6 % in 3 h of extraction process at 160 °C. LOC is highly thermal stable as analyzed by TGA-DTG. Using Lac:Oxa:ChCl (LOC), the highly pure lignin nanoparticles recovered were analyzed by FE-SEM, FT-IR, Zeta potential, TGA-DTG analysis. The Prepared NADES shows remarkable results in terms of selectivity, purity, recyclability, and recoverability are the main highlights of the present work. The extracted lignin has a potential role in application in biorefinery, healthcare, sensors, and polymer materials (such as adhesives, hydrogels).