Isolation and Characterization of Cellulose Nanocrystals from Date Palm Waste

Abstract

This study presents the isolation, characterization, and kinetic analyses of cellulose nanocrystals (CNCs) from date palm waste in the United Arab Emirates. After bleaching date palm stem waste with acidified NaClO 2 and delignification via NaOH treatments, cellulose was extracted. Mineral acid hydrolysis (62 wt % H 2 SO 4 ) was performed at 45 °C for 45 min to produce crystalline nanocellulose. Fourier transform infrared (FTIR) and chemical composition analysis confirmed the removal of noncellulosic constituents. The crystallinity index increased gradually with chemical treatments, according to the obtained X-ray diffraction (XRD) results. Thermogravimetric analysis and differential scanning calorimetry results revealed that the CNC has high thermal stability. The Coats–Redfern method was used to determine the kinetic parameters. The kinetic analysis confirmed that CNC has more activation energy than cellulose and thus confirms its compact and resistive crystalline structure. This has been attributable to the stronger hydrogen bonding in CNC crystalline domains than that in cellulose crystalline domains. Scanning electron microscopy revealed that lignin and hemicellulose were eliminated after chemical pretreatments, and CNC with a rodlike shape was obtained after hydrolysis. Moreover, transmission electron microscopy confirmed the nanoscale of crystalline cellulose. ζ potential analysis indicated that the CNC afforded a stable suspension (−29.27 mV), which is less prone to flocculation. Kinetic analyses of cellulose and cellulose nanocrystals isolated from date palm waste are useful for making composites and designing selective pyrolysis reactors.

Effect of Leaf Powdering Technique on the Characteristics of Date Palm-Derived Cellulose

“…In the bleaching process, raw samples were deprived of hemicellulose and some lignin, resulting in a higher crystallinity index. Following further lignification, the crystallinity index of the bleached sample increased, suggesting that lignin has been removed . According to Shi and Liu, the primary peak, designated as the diffraction intensity of crystalline zones, is represented by the I 002 peak intensity (the greatest intensity of the I 002 lattice diffraction), whereas the secondary peak denotes the diffraction intensity of the amorphous zone.…”

Cellulose nanocrystals isolated from corn leaf: straightforward immobilization of silver nanoparticles as a reduction catalyst

“… 50 In addition, some characteristic bands related to cellulose were observed, involving the band at 1400 cm −1 (the C–H and C–O bending vibrations from polysaccharides), the band at 1200–950 cm −1 (the stretching vibrations of C–O bonds), the band at 1060 cm −1 (the asymmetric bending vibration of the C–O–C ether bond from the pyranose rings in polysaccharides), the band at 895 cm −1 attributed to the β-glycoside linkage oscillations (the C–H combined with O–H bending vibrations) between glucose units of cellulose. 51 …”

“…Typically, the band at 1730 cm −1 (acetyl and ester groups from hemicellulose, or carboxyl group of ferulic acid and p -coumaric acid from lignin) and the band at 1240 cm −1 (the out-of-plane vibration of aryl group from lignin) were observed on untreated raw material and then extinguished after chemical treatments, evidencing the efficient removal of hemicellulose and lignin components from cellulose. 51 Briefly, the isolation of cellulose from corn leaf was successfully occurred by such a chemical treatment, in which the alkaline hydrolysis was of vital importance in removing most organic impurities other than cellulose and determining the crystalline structure of cellulose.…”

“…50 In addition, some characteristic bands related to cellulose were observed, involving the band at 1400 cm −1 (the C-H and C-O bending vibrations from polysaccharides), the band at 1200-950 cm −1 (the stretching vibrations of C-O bonds), the band at 1060 cm −1 (the asymmetric bending vibration of the C-O-C ether bond from the pyranose rings in polysaccharides), the band at 895 cm −1 attributed to the bglycoside linkage oscillations (the C-H combined with O-H bending vibrations) between glucose units of cellulose. 51 In general, the FT-IR spectra has obvious differences between untreated raw material and obtained cellulose. The vibrational bands derived from cellulose could be observed on all the samples, with an increase in intensity through each chemical treatment, in agreement with an increase in cellulose composition.…”

Synthesis, characterization and application of nanocrystalline cellulose: A review

“…NCC has a wide range of potential applications in various industries, including biomedical, electronics, packaging, and construction. For example, it can be used to reinforce polymers, create transparent films, and even produce drug delivery systems [6]. Additionally, NCC is a sustainable and renewable resource, as it is derived from plant-based sources and can be produced using environmentally friendly processes.…”