Deconstruction of Hemp Stalks by Hydrated Deep Eutectic Solvents for Lignocellulosic Nanofibrils Preparation

The compact hemicellulose and lignin network in hemp stalks restricts fiber nanofibrillation and dispersion stability. Herein, a molecular simulation-guided hydrated deep eutectic solvent (H-DES) strategy was developed for biomass deconstruction and lignocellulosic nanofibrils (LCNFs) production. Four acid-based H-DES systems containing choline chloride, organic acids, and water (1:2:4 molar ratio) were screened using electrostatic potential analysis, frontier molecular orbital calculations, and molecular dynamics simulations to evaluate their interactions with hemicellulose and lignin. The oxalic acid-based H-DES exhibited optimal deconstruction performance, removing 81.9% hemicellulose and 53.8% lignin while retaining cellulose I crystallinity. Subsequent ball milling produced well-dispersed LCNFs with an average diameter of 37.5 nm and a zeta potential of −29.8 mV. This work establishes a molecular-level strategy linking H-DES interactions with biomass deconstruction and nanofibrillation, enabling stable LCNFs dispersions through hemicellulose removal and partial lignin retention.