The Nanocellulose biorefinery: woody vs. herbaceous agricultural wastes for NCC production

Abstract

In the present work, the use of two agricultural residues (apple tree pruning and pea stalks) as source of nanocellulose was studied. Different pretreatments were applied to these lignocellulosic feedstocks from a biorefinery point of view: autohydrolysis, organosolv (acetosolv) and alkaline pretreatments. After a conventional bleaching step, the resulting cellulosic fractions were submitted to a classical acid hydrolysis for nanocellulose crystals NCC production. The results showed that after applying of different pretreatments, the resulting NCC’s presented differences in length (from 300 to 676 nm), surface charge (from 17 to 98 μmol acid groups/g NCC), purity (from 0.3% to 11.6% w/w of inorganics), crystallinity indexes and even allomorphism. These results highlighted the importance that cellulose source and particularly the applied pretreatments have on nanocrystals properties and suggest how biorefining pathway of lignocellulosic materials could lead to tailored NCC features (surface reactivity or chemical modification suitability).