Lignin Extraction and Characterization from Rice Straw by Organosolv Pulping Method

Rice straw has been acknowledged as one of the most abundant and cheap lignocellulosic biomass resources for potential use to produce chemical and biomaterials. In this study, lignin extraction from rice straw was done with formic acid and acetic acid by the Organosolv pulping system. The crude lignin was purified by 1, 4 dioxane and diethyl ether. The percent yield of purified lignin was 12.06%. The purified lignin fractions were characterized by non-destructive techniques such as Infrared spectroscopy (IR), Gas ChromatographyMass Spectrophotometer (GC-MS), Scanning Electron Microscope (SEM), Simultaneous Thermal Analysis (STA), etc. IR spectra confirmed the existence of lignin by showing the presence of alkyne stretch and aldehyde functional groups.The extracted lignin’s thermal properties were observed from Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA). The melting point of extracted lignin was supposed to between 250 and 275 °C; however, TGA found its melting point slightly above the range. GC-MS spectrum of purified lignin from rice straw showed the presence of vanillin and O-Guaiacol. Rice straw illustrated great potential to produce vanillin from purified lignin. SEM analyses indicate the presence of nanoparticles ranges 597 nm-200 nm frDepartment of Electrical and Electronic Engineering, Islamic University, Kushtia, Bangladeshom purified and crude lignin which is better for nanotechnology. Some particles under 200 nm also observed.