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.
