Cellulose and Lignocellulose Nanofibrils and Amphiphilic and Wet-Resilient Aerogels with Concurrent Sugar Extraction from Almond Hulls

Abstract

With downward pressure on the value of almond hulls (AHs), the major byproduct from the largest tree nut crop globally, the streamlined production of several grades of cellulose nanofibrils (CNFs) toward novel aerogels with concurrent sugar extraction was introduced to synergistically drive these products toward commercial adoption. Hot water extraction produced 50% lignocellulose (LC) with equal water-soluble sugars from AH of a soft-shell variety. Aqueous NaOH and NaClO 2 /KOH treatments isolated ca. 15% alkali cellulose and 12% cellulose, respectively. Coupled 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation and blending yielded 88, 91, and 95% LC micro-/nanofibrils (LCMNFs), alkali cellulose nanofibrils (ACNFs), and cellulose nanofibrils (CNFs) with, respectively, 0.76, 1.02, and 0.84 mmol/g surface carboxyls in a similar 4:1 width-to-thickness aspect ratio and ultrahigh length-to-thickness aspect ratios (800−1900). The LCMNF aerogel was mostly wet-resilient, wet-stable, and dry/wet shape-recoverable, whereas the most charged ACNFs gave the stiffest aerogel [31.6 kPa/(mg/cm 3 )].

One-pot extraction of nanocellulose from raw durian husk fiber using carboxylic acid-based deep eutectic solvent with in situ ultrasound assistance

“…These relatively lower transmittance values, significantly below those reported in previous studies [18] , highlight a complex and entangled structure in the synthesized CNF, leading to minimal visible light scattering. Consequently, the observed lower light scattering in the as-synthesized CNF suspension in this study can be attributed to its intricate and web-like entangled structure [43] . The analysis of lignin distribution in the resulting CNF suspensions was conducted at a fixed wavelength absorption ( Fig.…”

Regioselectively Carboxylated Cellulose Nanofibril Models from Dissolving Pulp: C6 via TEMPO Oxidation and C2,C3 via Periodate–Chlorite Oxidation

“…Carboxylation, either TEMPO [ 11 ] or sequential sodium periodate-sodium chlorite (PC) [ 12 ] oxidation, followed by high-speed blending, produced highly uniform CNFs in 97% yields, nearly a full conversion. The same coupled TEMPO-oxidation and blending approach has also been demonstrated to be highly efficient in producing over 92% and 95% CNFs from cellulose isolated from the almond shell [ 13 ] and hull [ 14 ], respectively.…”

Fostering Inclusive Scientific Communities: A Pathway to Innovation in Agriculture

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