Title
Valorization of waste rice straw: a green approach to preparation of lignin nanoparticles from waste biomass
Authors
TAHMIDUL ISLAM AQUIB, MOHAMMAD HELAL UDDIN and ROMANA AKTER NISHAT

Received July 29, 2025
Published Volume 60 Issue 1-2 January-February
Keywords lignin nanoparticles, nanocarrier, rice straw, valorization, waste biomass

Abstract
Rice straw is an abundant source of essential biopolymers such as cellulose, hemicelluloses, and lignin; however, the majority of global rice straw production remains underutilized. This study presents a novel approach to valorize waste rice straw through the extraction of lignin and subsequent preparation of lignin nanoparticles (LNPs). Alkali lignin (AL) was first extracted via alkaline treatment, followed by LNPs preparation through a simple acid precipitation method. The average yields of AL and LNPs were 10.72% and 21.08%, respectively. The nanoparticles were characterized using UV Visible spectroscopy, FT-IR, DLS and TEM. Results revealed that the LNPs were discrete, spherical, and well-dispersed, with an average particle size of approximately 201 nm and a polydispersity index (PDI) of 0.284 – well within the acceptable range for drug delivery systems.