Spanish Poplar Biomass as a Precursor for Nanocellulose Extraction

Abstract

The effect of acidic hydrolysis duration on nanocellulose size, morphology, and proper ties was investigated, which opens up a whole new horizon of versatility in poplar applications. This study aimed to examine Spanish poplar wastes as raw material to extract crystalline nanocellulose (CNC), which substantiates the importance of poplar wastes. Wastes were pulped using 1 L of 10% NaOH (wt./wt.) solution, and bleached several times by NaClO2; afterwards, white wastes were subjected to acidic hydrolysis by 60% H2SO4 for either 5, 10, or 15 min. Microcrystalline cellulose (MCC) underwent a similar hydrolysis protocol as poplar as control. TEM, IR, and XRD characterization techniques were performed. Poplar based nanocellulose sized 219 nm length and 69 nm width after 15 min acidic hydrolysis. MCC yielded 122 nm length and 12 nm width crystals after 10 min acidic hydrolysis. Hydrolysis resulted in a drastic change and intense peaks at 3500 and 2900 cm−1 for nanocellulose. Although pre-hydrolysis fiber treatment was not influencial on the crystallinity of poplar, acidic hydrolysis remarkably raised the crystallinity index (CI) by 7–8%. The more hydrolysis duration was prolonged, the size of the resulting crystal (whisker) decreased, and the aspect ratio increased. Hydrolysis was more impactful on MCC than poplar. However, for future work, it seems that longer duration of pulping and bleaching could have significantly removed unwanted components (hemicellulose and lignin), showcased in IR and XRD, and hence smoothened the following hydrolysis.

Superhydrophobic Poplar Scrimber Via In Situ Synthesis of Cu7Cl4(OH)10·H2O Heterostructure Inspired by Pine Cone with Superultraviolet Resistance

“…The crystalline parameters of cellulose from modified poplar scrimber and poplar wood control , as well as Cu 7 Cl 4 (OH) 10 ·H 2 O particle − were summarized in Figure d, and these values are consistent with those of other reports.…”

Nanocellulose-Based Nanocomposites for Sustainable Applications: A Review

“…Mechanical routes for nanocellulose production are the processes where cellulose fibrils were subjected to high shear force to cleavage the cellulose fiber in the longitudinal axis, resulting in CNF. The most common mechanical approaches for CNF production include grinding, cryocrushing, high-pressure homogenization, ultrasonication, steam explosion, and ball milling methods [118].…”

“…This method was preferred due to its simplicity, high efficiency, and no requirement for organic solvent for biomass refining [89]. The mechanism of this technique is bypassing the cellulose slurry into the vessel with high pressure and high velocity, which the impact force and shear force in the fluid lead to the cleavage of cellulose microfibrils into nanometer-size cellulose [118]. During this process, the suspension viscosity will be changed from low to high viscosity.…”

“…This process allows the defibrillation of the cellulose fibers through the movement of the balls in the rotating jar and creates a shear force to defibrillate the cellulose fiber. The ball milling process was used to grind native cellulose fibers to produce amorphous cellulose with decreasing crystallinity, size, and morphology, with changes in the crystalline lattice [118]. Another method for the isolation of nanocellulose is cryocrushing, where the fiber is treated with liquid nitrogen to obtain ice crystals to impart larger pressure within the cell wall, leading to an explosion of the cell wall to form the CNF [105].…”

Perspective Chapter: Potential of Lignin Valorization with Emphasis on Bioepoxy Production

“…In general, it is an amorphous, isotropic material, covered, for example, in the wooden stem of a plant. All plants and algae comprise lignin in different amounts, in addition to cellulose and hemicellulose [5,6]. Lignin amount also differs according to the time of harvesting.…”