A multistep mild process for preparation of nanocellulose from orange bagasse

Abstract

Orange bagasse in natura and industrial orange bagasse were investigated as starting materials for the production of nanocellulose under moderate chemical sequential extraction conditions. The latter accounted for acid (5% v v−1 and 100 °C) and/or alkaline conditions (NaOH 1.6–4.0% m v−1, 120 °C); and bleaching with NaClO2 (1–3% m v−1, 80 °C). Ultrasound treatment yielded very similar cellulose nanofibers with 60–70% of crystallinity and highly pure (over 98%). As seen by field emission scanning electron microscopy, cellulose nanofibers showed mean diameters of 18.4 nm ± 6.0 nm from bagasse in natura, while 20.5 nm ± 7.0 nm mean diameters were observed for the nanofibers isolated from the industrial bagasse. Crystallinity indices were determined using X-ray diffraction and solid-state nuclear magnetic resonance (CP–MAS 13C NMR) data. The obtained materials have numerous potential applications and represent a green alternative for the treatment of orange fruit biomass.