DOI: https://doi.org/10.55373/mjchem.v26i5.562

Keywords: Nanocellulose; acid hydrolysis; crystallinity; rice husk

Abstract

In this study, nanocellulose (NC) was produced chemically from rice husk (RH) by alkaline extraction, bleaching, and acid hydrolysis. The effect of different sulphuric acid (H2SO4) concentrations (8%, 10%, 12%, 14%, and 16%) on the yield of NC was examined. The characteristics of NC were studied using Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The highest NC yield was obtained at 12% H2SO4. The FTIR spectra of NC showed prominent peaks corresponding to cellulose. Based on FESEM analysis, NC constituted a rod-like structure that was completely cleaved in a range of 12%–16% H2SO4. The TEM analysis showed the NC fibre was found to be in the range of 8–50 nm. The XRD analysis demonstrated that the crystallinity index and crystallite size of NC increased when the H2SO4 concentration increased up to 12%. The primary XRD peaks at 2θ = 18°, 22°, and 34° were not affected during acid hydrolysis. The thermal degradation of all NC samples was higher than the raw RH, showing that the NC was stable at high temperatures of more than 300 °C; however, as H2SO4 concentration increased, the thermal stability decreased. Different H2SO4 concentrations give significant changes to the physicochemical properties of NC from RH.