Cellulose nanofibers from rapidly microwave-delignified energy cane bagasse and their application in drilling fluids as rheology and filtration modifiers

Energy cane bagasse (ECB) is the major residue after the cane is milled to extract juice for sugar, biochemical, and/or biofuel production. The sustainable conversion of ECB into high value-added products can help reduce agricultural waste, and enhance utilization of bioresources. In the present work, we demonstrate that ECB can be converted into cellulose nanofibers (CNFs) that can serve as high value-added additives in bentonite water-based fluids (BT-WDFs). Particularly, cellulose fibers (CFs) were rapidly isolated from ECB by microwave-assisted NaOH / NaClO2 treatments. CFs treated with the higher NaOH concentration and microwave irradiation lost more lignin (96.2 % delignification) and their crystal structure was more completely transformed from cellulose I to II, resulting in smaller diameters (8.5 μm). CNFs suspensions from subsequent wet-grinding and microfluidization of the CFs exhibited typical shear-thinning behaviors and solid-like viscoelastic properties due to the entangled network structure of the CNFs. Formulated fluids with 0.5 wt% of the manufactured CNFs showed good rheological and filtration properties, demonstrating their potential applications in the oil service industry.