Isolation of cellulose nanocrystals from rice husk using the formic/ peroxyformic acid process

Abstract

Cellulose nanocrystals (CNCs) is one of the interesting materials attracting many researchers from the decades, especially when they are extracted from natural biomass resources. The aim of this study was to explore the utilization of rice husk residues as source for the production of CNCs. Cellulose was extracted from rice husk based on chemical method, using the formic/ peroxyformic acid process in order to effectively remove lignin and hemicelluloses from raw material. The cellulose was then treated by acid hydrolysis process performing at 45oC for 30 min, using 15 mL of H2SO4 (64% wt) for each gram of cellulose. The material obtained after each stage of the treatments was carefully characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Morphological characterization from TEM revealed the appearance of needle-like shaped CNCs, average diameter and length of 15 nm and 480 nm, respectively. FT-IR results indicated that lignin was completely removed from the samples during chemical treatment. The thermal stability of the materials in successive treatments was also investigated using thermogravimetric analysis (TGA). These promising results proved revalue of this by-product for the production of CNCs and its potential use as reinforcement in the preparation of nanocomposites.