Structural analysis of cellulose fibers and rice straw ash derived from Sri Lankan rice straw

Abstract

Being an agricultural country, Sri Lanka generates over eight million metric tonnes of rice straw per annum as a byproduct of the paddy cultivation. Currently rice straw is burnt or ploughed into the field without being converted into a productive output. One such output can be isolating the cellulose fibers from this under-utilized waste material. The availability of rice straw is highly seasonal. In this study, cellulose fibers were extracted from rice straw via a three step chemical purification method straw which yeielded 33.4 ± 0.52 percent. The structure, chemical composition, morphology and thermal properties of rice straw, cellulose and rice straw ash were investigated using laser diffracted particle size analyzer, Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometer, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). FTIR results and SEM images show the removal of lignin and hemicellulose and silica at each step of the isolation process. XRD results exhibit the increase in crystallinity of the fibers. This study reveals that thermal and structural properties have increased after the chemical isolation and purification treatment.