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.