Fenton-like oxidation of pinewood to produce cellulose nanoparticles in one pot treatment

The conventional production of nanocellulose from biomass demands multiple steps involving numerous chemicals like corrosive acids, bases, halogenated bleaching agents, and mechanical energy. This research aims to find a greener approach to producing nanocellulose particles from biomass. In nature, the brown rot fungi utilize iron complex and hydrogen peroxide to overcome the lignin boundary and approach cellulose in biomass. This fact encouraged us to use the same oxidative catalytic system on biomass in a one-pot process. Pinewood sawdust was taken as starting material, and the iron oxide, hydrogen peroxide oxidation system was applied with varying the concentration of hydrogen peroxide and the reaction time. In 6 h, a one-pot system obtained a 95% pure cellulose with an aspect ratio of 1–15 from pinewood sawdust. The yield of the process was very high, i.e., from the total cellulose content in pinewood, 85% of cellulose was recovered in this process. The degree of polymerization of the obtained cellulose product was 100 ± 20, with an aspect ratio of 1–20. The particles were sphere and ellipsoidal-shaped, with the majority having a diameter of 120–180 nm. It had a crystallinity of 81%, an increase of 26% crystallinity was observed compared to the untreated pinewood sawdust. These nanocellulose particles would be a promising material for different derivatizing reactions, with their high surface area (15.0 ± 0.5 m²/g) and low degree of polymerization. This developed one-pot process has avoided using hazardous chemicals to produce nanocellulose particles. Graphical abstract: [Figure not available: see fulltext.]