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

Afacile,greenandeconomicalmethod for
the high-efficiency utilization and functionalization of bamboo fiber could significantly improve the devel-
opment 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 showedthatmostoftheligninwasefficientlyremoved (94.39%)and91%ofthe cellulose was recoveredafter
the moso bamboo was pretreated with ChCl–LC at
120 ℃ for 3 h with a solid-to-liquid ratio of 1:25.
Furthermore, nanofibers with widths of 20–80 nm
were successfully preparedfrom 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.

一种简便、绿色且经济的竹纤维高效利用与功能化方法，可显著推动生物质产业的发展。本研究采用由氯化胆碱（choline chloride, ChCl）与乳酸（lactic acid, LC）复配形成的低共熔溶剂（deep eutectic solvent）作为预处理试剂，对毛竹（Phyllostachys pubescens）进行脱木质素处理并制备纳米纤维素（nanocellulose）。实验结果表明，当采用固液比1:25的ChCl-LC体系在120℃下预处理毛竹3小时后，木质素脱除率可达94.39%，纤维素回收率达91%。进一步通过简易机械工艺对预处理后的纤维进行处理，可成功制备出宽度为20~80 nm的纳米纤维。扫描电子显微镜（scanning electron microscope, SEM）与原子力显微镜（atomic force microscope, AFM）表征结果显示，该纳米纤维具有优异的长径比。此外，所制备的纳米纤维可用于制备高强度薄膜，其拉伸强度可达163~213 MPa。