A low-cost environmentally friendly approach to isolate lignin containing micro and nanofibrillated cellulose from Eucalyptus globulus bark by steam explosion

Abstract

Micro- and Nano-Fibrillated Cellulose (MNFC) have gained increasing attention due to their remarkable properties, but their production usually requires an intensive multi-step process. This study proposes to find a novel approach involving steam explosion for the production of lignin-containing micro- and nano-fibrillated cellulose (L-MNFC) using Eucalyptus globulus bark as a new lignocellulosic feedstock. Eucalyptus globulus bark was first pre-treated by steam explosion in alkaline conditions (200 °C, 8 min) or by soda cooking in a rotating autoclave (170 °C, 60 min), refined and then ground until gels formed. The chemical composition of the pulps was studied with ion chromatography and FTIR-ATR. The morphology of the products was studied with measurements of suspension turbidity and Morfi Neo, optical and atomic force microscopies. Nanopapers were produced from L-MNFC to investigate mechanical properties. Results obtained showed that steam explosion produced pulps with slightly higher lignin content (≈ 9%), containing shorter fibers (≈ 400 µm) and higher amounts of fines (≈ 86%) compared to soda cooking (≈ 5%, ≈ 560 µm and 66%, respectively). AFM images of SteamEx L-MNFC gels showed a web-like structure containing lignin nanoparticles.Graphical abstract