Lignin in pulp is chemically and physically bonded to cellulose and hemicellulose
forming a three-dimensional polymer complex that contains acetal, [alpha] phenyl-[beta]-ether, phenyl-[beta]-glucosidic and hydrogen bonds [9, 25-27].
Crop residues are high in cellulose, hemicellulose
and lignin, but low in pectin and silica.
Figure 3 shows the relative intensity RI of the absorption of the chromophore C=O stretching vibration at 1730 [cm.sup.-1] ([RI.sub.1730]), the absorption of the lignin C=C stretching vibration at 1510 [cm.sup.-1] ([RI.sub.1510]), and the absorption of the cellulose and hemicellulose
OH in-plane deformation/CH bending vibration at 1330 [cm.sup.-1] ([RI.sub.1330]) during Xe-WOM CAM 0 exposure.
Treatment with heat, pressure, or acids first removes hemicellulose
and lignin from the long cellulose fibers.
The recycled material had much higher levels of nitrogen and lower levels of cellulose and hemicellulose
indicating lower levels of carbon compounds.
There is a slight increase in cellulose content, while the content of the cementing vegetable substances is reduced: hemicellulose
by 24%, pectin by 86%, and lignin by 20%.
Cellulose and hemicellulose
can be broken down into sugars to produce alcohol and biofuels, making trees an important potential energy source.
The topics covered include biomass derivatives; carbon dioxide as a renewable C1 feedstock; hemicellulose
from biodelignified wood; optimization of the process conditions for the extraction of heteropolysaccharides from birch; and protein-based plastics and composites as smart green materials.
"The opportunity to recover energy value from waste hemicellulose
as part of the emerging forest biorefinery concept will generate new applications for performance chemicals to further benefit paper-maker profitability," he added.
was determined by difference (NDF-ADF).
Notice that the hemicellulose
and lignin fractions are split between crude fiber and nitrogen-free extract.
The report defines biomass as all plant-derived molecules, including grain, starch, sugar, oil, and waste products, as well as the plant structural components cellulose, hemicellulose
, and lignin.