Production of lignin-containing nanocellulose from poplar using ternary deep eutectic solvents pretreatment

Abstract

Developing green and sustainable reagents and materials is of great significance for the lignin-containing nanocellulose (LNC) production. In this study, new green ternary deep eutectic solvents (DESs) pretreatment followed by microfluidization were used to prepare LNC from poplar. Under optimal pretreatment conditions (choline chloride: lactic acid: p-toluenesulfonic acid molar ratio of 2:10:1, 100 °C), ultrafine ribbon-like LNCs about 23.29 nm wide and 1.16 nm thick with uniformly distributed spherical lignin particles were obtained. The yield of the LNC reached 64.65%. The LNC exhibited cellulose I crystal structure, good dispersion stability in water and high lignin content of 27.65%. The LNC also possessed high thermal stability (Tmax = 370 °C). Additionally, the LNC suspensions showed high viscosity and strong gel-like behavior. The novel ternary DESs pretreatment combined with microfluidization process offers a promising route in converting hardwood biomass into value-added LNC.