Isolation and Physicochemical Characterization of Lignin from <i>Chromolaena Odorata</i> and <i>Tithonia Diversifolia</i>

Abstract

This study dealt with isolation of lignin from soft woods namely; Chromolaena odorata (Siam Weed) and Tithonia diversifolia (Mexican Sunflower) using alkali pretreatment method. The raw samples were characterized by some physico-chemical parameters before extraction. Chromolaena odorata gave higher lignin yield and lesser ash content of 15.12 % and 4.22 % respectively compared to Tithonia diversifolia with 7.40 % and 9.56 % respectively. The isolated lignins were characterized by some physico-chemical parameters and spectroscopy methods like Futran Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). Lignin from Chromolaena odorata was found to be more pure than the one from Tithonia diversifolia as evident from the values of ash content (4.22%) and klason lignin (33.65 %) for Chromolaena odorata while ash content (9.56 %) and klason lignin (21.96 %) were obtained from Tithonia diversifolia. The FT-IR spectra of both lignins revealed the presence of syringyl and guaiacyl units.

Keywords: Chromolaena odorata, Tithonia diversifolia, Lignin, FT-IR, Physico chemical parameters