Valorization of royal palm tree agroindustrial waste by isolating cellulose nanocrystals

A considerable increase in royal palm cultivation as a result of industrialization of canned heart of palm has generated large amounts of renewable lignocellulosic waste, but reuse is still rarely practiced. In this work, for the first time, cellulose nanocrystals (CNCs) were extracted from the leaf sheath discarded from the royal palm harvest. Chlorine-free purification methods were used and strong acid hydrolysis synthesis with different times and temperatures were performed. The purification treatments removed lignin successfully, reducing its content from 10.4% to 1.0%. The formation of spherical and rod-shaped CNCs reached yields between 7.9% and 48.8%, which was confirmed by a significant increase in crystallinity from 38.9% of natural fiber to 63.6% and 79.6% of CNCs, depending on temperature and synthesis duration. The production of CNCs from this underutilized waste has the potential to add value to royal palm tree crops, in addition to significantly reducing the volume of cumulative waste in the environment.