Extraction and characterization of rice straw cellulose nanofibers by an optimized chemomechanical method

Abstract

In this study, a chemomechanical method was performed to extract nanofibers from rice straw. This procedure included swelling, acid hydrolysis, alkali treatment, bleaching, and sonication. X-ray diffractometer was employed to investigate the effect of acid hydrolysis conditions and other chemical treatments on the chemical structure of the extracted cellulose fibers. It was concluded that by increasing the acid concentration and hydrolysis time, the crystallinity of the extracted fibers was increased. The optimum acid hydrolysis conditions were found to be 2M and 2 h for the acid concentration and hydrolysis time, respectively. The chemical compositions of fibers including cellulose, hemicelluloses, lignin, and silica were determined by different examinations. It was noticed that almost all the silica content of fibers was solubilized in the swelling step. Moreover, the achieved results showed that the cellulose content of the alkali treated fibers was increased around 71% compared to the raw materials. ATR-FTIR was applied out to compare the chemical structure of untreated and bleached fibers. The dimensions and morphology of the chemically and mechanically extracted nanofibers were investigated by scanning electron microscopy, field emission scanning electron microscopy, and transmission electron microscopy. The results of the image analyzer showed that almost 50% of fibers have a diameter within a range of 70-90 nm and length of several micrometers. The thermal gravimetric analyses were performed on the untreated and bleached fibers. It was demonstrated that the degradation temperature was increased around 19% for the purified fibers compared to raw materials.

Comparative Study on Extraction of Cellulose Fiber from Rice Straw Waste from Chemo-Mechanical and Pulping Method

“…After the bleaching step, almost all the remain lignin is removed. Therefore, the brightness of the CP was increased [ 36 ]. The dispersion of NaOH in the amorphous area disrupted the intermolecular bonds, which was due to the internal stress in plant cell wall, thus inducing the removal of the non-cellulosic parts of RS [ 45 ].…”

“…In that way, agriculture waste can be turned into wealth, which also helps in managing the biomass effectively. These two routes were created with slightly altered parts, based on previous study procedures [ 35 , 36 ]. The selection of these two methods was in consideration of cost, safety, and time consumption during the process.…”

Influence of Hydrolysis Conditions on Characteristics of Nanocrystalline Cellulose Extracted from Ramie Fibers by Hydrochloric Acid Hydrolysis

“…The more crystalline component of NCCs compared to both raw ber and CPC might be believed to be responsible for the higher thermal stability of NCCs [Mohamed et al 2017]. In addition, the lower decomposition temperature of raw ber was associated with the low degradation temperature of hemicellulose, lignin, and pectin [Chen et al 2011;Nasri-Nasrabadi et al 2014]. Furthermore, the onset temperature of NCC prepared under acid concentrations of 6, 8, and 12 are 254, 253, and 252 °C, respectively.…”

Facile preparation and separation performances of cellulose nanofibrous membranes

“…15 This method has been employed for the fibrillation of cellulose with nanoscale structures, the majority of which have primarily been produced from natural raw material sources. [16][17][18][19][20][21] Different dimensions of cellulose nanostructures are realized depending on the starting material, operating conditions and pretreatments used. HIUS has the advantage of maintaining the originality of the fibers in terms of length and structure.…”

“…The sonochemical synthesis of various nanostructured inorganic materials have also been reported for instance . This method has been employed for the fibrillation of cellulose with nanoscale structures, the majority of which have primarily been produced from natural raw material sources . Different dimensions of cellulose nanostructures are realized depending on the starting material, operating conditions and pre‐treatments used.…”