Opportunities for Ivory Nut Residue Valorization as a Source of Nanocellulose Colloidal Suspensions

Abstract

Ivory nut seeds have been traditionally exploited in Central and South America for obtaining vegetable ivory. The residues from this industry are susceptible to valorization as a source of fatty acids (by organic extraction) and mannans (by alkaline dissolution and regeneration). Nonetheless, cellulose may also be recovered at the end of this fractionation process by acid hydrolysis and functionalization, with associated advantages over other lignocellulosic sources due to the absence of lignin in the endospermic tissue. In this work, various experimental parameters (sulfuric acid concentration, temperature, and hydrolysis time) were investigated to optimize the processing conditions for preparing stable nanocellulose suspensions after ultrasonication. The most stable nanocellulose gel (1 wt% solid content) was obtained after 4-h hydrolysis at 60 °C with 8 M H2SO4 and was characterized by using complementary tech-niques, including dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), nano-fibril sulfation measurements, vibrational and solid-state nuclear magnetic resonance (CP/MAS 13C-NMR) spectroscopies, and thermal analysis. This nanocellulose hydrogel is susceptible to further utilization in various applications and fields, e.g., in agricul-ture for controlling the release of agrochemicals, in pharmaceutics for developing new dosage forms, and in the treatment of wastewater from the textile and paper industries.

Nanocellulose preparation from diverse plant feedstocks, processes, and chemical treatments: A review emphasizing non-woods

“…Carvajal-Barriga et al (2022) used the sulfuric acid hydrolysis method followed by ultrasonication to produce nanocellulose from ivory seeds. They reported that stable nanocellulose gel (1% solid content) could be obtained after 4 h of hydrolysis at 60 °C using 8 M H2SO4 (Carvajal-Barriga et al 2022). Another example, using green vegetable waste such as lettuce, leek, and artichokes as feedstocks, was demonstrated by Sanchez-Salvador et al (2022b).…”

Plasma‐induced formation of coatings on vegetable ivory microparticles immersed in silicone oil: Enhancing surface coverage using natural products

“…[11] As a subtractive manufacturing process, the production of vegetable ivory ornaments produces a powder residue which may correspond from 65% to 88% of the original material. [12] These particles have no current valorization strategy and are a potential source of mannan, nanocellulose, and pyrolysis products [9,12,13] owing to their high carbohydrate content (ca. 70 wt% homomannan and 7.5 wt% cellulose).…”