A green extraction technology of lignocellulose from cassava residue by mechanical activation-assisted ternary deep eutectic solvent

Lignocellulose (LC) is a natural polymer material that holds immense potential for various applications. However, extracting LC from biomass wastes with high-starch content has been challenging due to low selectivity and yield. In this study, LC was prepared from cassava residue (CR) via a combination of mechanical activation pretreatment and a citric acid (CA)-enhanced ternary deep eutectic solvent (TDES) consisting of choline chloride (ChCl), lactic acid (LA), and CA. The mechanical activation reduces the size of CR, greatly promoting the removal ability for starch, lignin and hemicellulose using TDES, and thus improving yield and selectivity of LC through this method. The CA esterified LC to prevent its excessive hydrolysis and increased a significantly higher LC content (82.52 wt%) compared to mechanical activation only and DES without CA, increasing by 6.97 times and 1.26 times, respectively. The extraction temperature significantly affected the structure, composition, thermal stability of LC and the properties of recovered TDES. The LC extracted at 90 degrees C (LC-90) had the highest cellulose content (82.52 wt%), crystallinity index (44.82 %), and higher degradation temperature (339.7 degrees C). The properties of the recovered TDES and extraction mechanism were analyzed. This study provides a strategy for the high-value utilization of biomass waste.