Choline chloride-lactic acid deep eutectic solvent for delignification and nanocellulose production of moso bamboo

A facile, green and economical method for the high-efficiency utilization and functionalization of bamboo fiber could significantly improve the development of biomass industries. Here, we demonstrated a deep eutectic solvent, which formed from choline chloride (ChCl) and lactic acid (LC), as pretreating agent to delignify moso bamboo (Phyllostachys pubescens) and produce nanocellulose. The results showed that most of the lignin was efficiently removed (94.39%) and 91% of the cellulose was recovered after the moso bamboo was pretreated with ChCl–LC at 120 °C for 3 h with a solid-to-liquid ratio of 1:25. Furthermore, nanofibers with widths of 20–80 nm were successfully prepared from pretreated fibers after a simple mechanical process. SEM and AFM images showed that they have excellent aspect ratio. In addition, the obtained nanofibers could be used to fabricate strong films which feature a high tensile strength ranged from 163 to 213 MPa.