Synthesis and characterization of cellulose nanocrystals derived from walnut shell agricultural residues

Isolation of Cellulose Nanofibers from Oryza sativa Residues via TEMPO Mediated Oxidation

“…Moreover, it has been reported that particle morphology and degree of aggregation are dependent on TEM sample preparation, though some fibers remained isolated which facilitated the determination of fiber length with the help of image processing software (Collazo-Bigliardi, Ortega-Toro, and Boix 2018). The length distribution of cellulose isolated from rice husks is similar to those that have been reported in the literature when acid hydrolysis was employed to isolate cellulose from different biomass, such as for acid hydrolyzed rice husks cellulose (Collazo-Bigliardi, Ortega-Toro, and Boix 2018), vine shoots (El Achaby et al 2018), walnut (Hemmati et al 2018) and roselle fibers (Kian et al 2017). The nanofiber widths are almost constant, irrespective of cellulose source, whereas the lengths are widely distributed and varied depending on the oxidation and disintegration conditions.…”

“…With a global production of 220 billion tonnes annually, agricultural residues have attracted attention as precursors for the production of environmentally sustainable materials (Islam et al 2018;Jorfi and Foster 2015;Kar, Rana, and Pandey 2015). Residues such as rice husks (Barbash, Yaschenko, and Shniruk 2017;Begun et al 2013), coffee husks (Collazo-Bigliardi, Ortega-Toro, and Boix 2018), wheat straw (Bian, et al 2019a), sisal fibers (Bhimte and Tayade 2007), walnuts (Hemmati et al 2018), corn cobs (Boufi and Chaker 2016), cladophora fibers (Camacho, Gerongay, and Macalinao 2013), lotus stalks (Chen et al 2014), vine shoots (El Achaby et al 2018), roselle (Kian et al 2017), or agave (Ponce et al 2013) are rich sources of cellulose nanofibers with potential applications in composite materials (Torres et al 2013). In developing countries such as Kenya where the annual rice production stands at 45,000-50,000 tons per year, these residues are increasingly becoming a point of concern due to the high amount generated annually.…”

A Review on Surface-Functionalized Cellulosic Nanostructures as Biocompatible Antibacterial Materials

“…The most common recipe to synthesize acid-hydrolyzed CNCs is mixing 64 wt% sulfuric acid with cellulose in a ratio of 8.75-17.5 mL g −1 at 45 °C for 25-45 min [89]. Sulfuric acid cleaves and dissolves the amorphous chains of cellulose fibers, freeing up the crystalline parts as CNCs [90,91]. The CNCs produced by this method are negatively charged and form a stable colloidal suspension, although their thermal stability is lower compared to that of cellulose [92].…”

Relationship between Structural Characteristics of Cellulose Nanocrystals Obtained from Kraft Pulp

“…Hemmati et al [23] studied CNCs production from walnut shells, describing their physicochemical attributes, such as crystallite size, crystallinity and thermal stability, among others. The results indicated that the mean diameter of the nanostructures was 130 nm, the crystallinity of the walnut shells was 49% and after acid/alkaline hydrolysis it increased to 60%, TGA analysis revealed that the thermal stability of the CNCs was lower compared to normal cellulose.…”