Advancing circular economy: Biorefinery of agri-waste via green multicomponent deep eutectic solvent pretreatment

Abstract

An effective, economical, and eco-friendly pretreatment of lignocellulosic biomass is crucial for advancing biorefinery as a sustainable solution to fossil fuel scarcity and to support a circular economy. This study introduces a multifunctional deep eutectic solvent (multi-DES) system, created by combining analog volatile fatty acids (analog-VFAs) as hydrogen bond donors with choline chloride, to pretreat agricultural waste (agri-waste) and facilitate the production of nano-lignocellulose materials. The multi-DES pretreatment was optimized for varying durations and temperatures, achieving a maximum lignin removal rate of 74.1 % at 150 °C over 3 h. Subsequent ball milling yielded high-quality lignocellulosic nanofibers (LCNFs) with widths ranging from 10 to 15 nm and exhibiting excellent thermal stability and mechanical properties. A life cycle assessment (LCA) confirmed the environmental benefits and practical viability of this biorefinery process. This approach effectively upgrades agri-waste into valuable LCNFs, enhancing biomass utilization with minimal environmental impact, and advancing the competitiveness of biorefineries.