Preparation of cellulose micro- and nano fibers from bagasse through deep eutectic solvent system

Abstract

This study aimed to prepare the cellulose micro- and nanofibers (CMNFs) using green chemistry viewpoint. The CMNFs were fabricated from sugarcane bagasse (SCB) pulp through treatment with zinc chloride (ZnCl2) - lactic acid (LA) in deep eutectic solvent (ZnCl2-LA DES) followed by short time ultrasonication of the DES-treated fibers in water. Under the optimum condition, the SCB pulp at high solid loading of 6.25% was treated with ZnCl2-LA DES. Lactate functionalized CMNFs with 230-270 nm length and 15-16 nm width were resulted in more than 90% yield and up to 62.2% crystallinity. The results showed that ZnCl2-LA DES was a multi-functional green solvent by acting as solvent, catalyst, and substrate. Also, the ZnCl2-LA DES could be reused for more than 5 times with slight decrease of performance. Zinc ion could be separated from ZnCl2-LA DES after used with simple precipitate method and the remained solution mainly contained of saccharides and lactic acid which can be disposed safely after neutralization or used as substrate for fermentation. Overall, ZnCl2-LA DES treatment followed by ultrasonication had proven to be effective and environmentally friendly procedure for preparation lactate functionalized CMNFs from SCB pulp.