Extraction of thermally stable cellulose nanocrystals in short processing time from waste newspaper by conventional acid hydrolysis

Abstract

Motivated by many exclusive and useful features of cellulose nanocrystals (CNC) and the underutilized resource of waste newspaper, this study aimed to extract CNC from waste newspapers by means of alkali and bleaching treatments followed by acid hydrolysis. The morphological structure of the obtained CNC was analysed by optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. The remarkable removal of surface contamination and the reduction in fiber diameter during alkali and bleaching treatment were observed and the nano-dimension of the extracted CNC was revealed with the average diameter of 12.3±2.8 nm. Characterization of the extracted CNC showed a high whiteness index of 80%, and high transparency of about 80% of the light at 600 nm calculated for a 0.02 mm thick nanocellulose film. Fourier transform infrared spectroscopy (FTIR) indicated that lignin, hemicellulose and other coloring agents were successfully removed. A comparably high crystallinity index of 80.15% was calculated from x-ray diffraction data. Thermogravimetric analysis showed that the product had a typical maximum thermal degradation at 300°C. The analysis results indicated the successful extraction of good CNC from waste newspaper with the shortest processing time ever reported for acid hydrolysis with conventional alkali and bleaching pretreatment. The findings also strongly support for further research of nanocomposites reinforced by CNC produced from waste newspaper.

Cellulose Nanocrystals (CNCs) and Cellulose Nanofibers (CNFs) as Adsorbents of Heavy Metal Ions

“…Tis also shows that the CPC-GNS particle synthesis process using NaOH can remove noncellulose compounds. Ten the adsorption peak of 3410 cm −1 on the CNC-GNS (spectrum c) has a high intensity, which proves that the noncellulose component in the CNCS-GNS particles has disappeared [72,117,118].…”

“…Homogenization, grinding, and ultrasonication methods are several types of CNF synthesis methods that have been widely used in previous studies [50,97,98,116,117]. According to some research, the pretreatment process came frst, followed by the mechanical synthesis process.…”

Effects of reaction conditions on the degree of substitution in acetylated nanocellulose

“…The obtained CNC was characterized and reported in [20]. In summary, CNC rods with an average diameter of 12.3 ± 2.8nm.…”

“…CNC extracted from waste newspapers by means of alkali and bleaching treatments followed by acid hydrolysis as reported in [20] was used in this study for acetylation. First, 5 g of the ground newspaper containing inks were added to 300 mL of 2 wt% of NaOH solution at 100 ℃ in 3 h under continuous stirring, then rinsed with water until pH = 7.…”

Synthesis and Characterization of Corn Husk (Zea Mays L.) Cellulose Using Microwave-Assisted Extraction (MAE)

“…Cellulose can be synthesized by various methods, such as using alkalis and organic alkalis [8,9], acid hydrolysis [10,11], enzymatic [12,13], steam explosion [14], and reactive extrusion [15]. All those methods are conventional, time-consuming, inefficient in solvent usage, and necessitate elevated temperatures.…”