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Torréfaction de la biomasse lignocellulosique dans les liquides ioniques: Analyse comparative par spectroscopies de surface
Author(s) -
Chérif HadjAhmed,
Larachi Faical,
Adnot Alain,
Sarvaramini Amin
Publication year - 2014
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.21998
Subject(s) - torrefaction , lignin , ionic liquid , cellulose , chemistry , x ray photoelectron spectroscopy , nuclear chemistry , materials science , chemical engineering , organic chemistry , pyrolysis , catalysis , engineering
Torrefaction is a thermal pretreatment used to improve the physicochemical properties of lignocellulosic biomass prior to its thermochemical conversion. In this study, aspen wood imbued with a hydrophilic ionic liquid (1‐ethyl‐3‐methyl imidazolium trifluoromethanesulfonate) was torrefied, and the properties of the solid product were compared to those from conventional dry torrefaction. The solid products were characterized using X‐ray photoelectron spectroscopy X (XPS), photoelectron energy loss spectroscopy (ESCALOSS), and X‐ray excited Auger electron spectroscopy X (XAES) in order to study the biomass surface modifications due to ionic‐liquid torrefaction in comparison to dry torrefaction. The results obtained show that ionic liquids led to lignin degradation while dry torrefaction mostly affected the carbon‐rich extractives. Lignin degradation was monitored using ESCALOSS and XAES techniques, which unveiled reduction in sp 2 hybridized carbon forms. Finally, ionic‐liquid assisted torrefaction of the main biomass components, i.e., lignin, cellulose and hemicellulose, treated individually, showed a decrease in their O/C ratio in line with improved hydrophobicity and robustness against moisture uptake by the torrefied products. The diversity of trends revealed by our surface analysis study during the torrefaction of bare or ionic‐liquid‐impregnated wood, especially by means of ESCALOSS and XAES, requires the pursuit of research in order to describe more in‐depth the physicochemical processes involved during torrefaction.