Characterization
of isolated lignin from eucalyptus wood chip obtained by liquid hot water process
Suriyachai Nopparat, Khongchamnan Punjarat, Laosiripojana Navadol, Kreetachat Torpong
and Imman Saksit
Res. J. Chem. Environ; Vol. 25(9); 118-126;
doi: https://doi.org/10.25303/259rjce118126; (2021)
Abstract
In this study, we propose a novel optimization for lignin isolation from the eucalyptus
wood chip (EWC) under hydrothermal liquid hot water (LWH) process in the presence
of alkaline catalyst (NaOH). The optimal conditions were obtained employing response
surface methodology (RSM). The optimal condition was 160°C for 30 min in the presence
of alkaline catalyst of 0.020 M. This condition demonstrated the highest lignin
extraction with solid fraction of 77.3% and 76.1%. In addition, the physicochemical
structure of isolated lignin was characterized with diverse techniques. The lignin
recovery from liquid phase’s GPC analysis illustrated a high average Mw/Mn (17500/7450
g/mol) while polydispersity index (2.34) was lower in comparison with the commercial
organosolv lignin. The TGA analysis showed the maximum decomposition of lignin recovery
at 140 to 350oC.
Furthermore, the Py/GCMS analysis showed a predominance of 57.63% of syringyl units
(S) over 37.37% of guaiacyl units (G) under optimal conditions. The results revealed
that the integrated process was a potential approach to add more value in the employment
of the agricultural waste material.
