Switchgrass
(
Panicum virgatum
, L.,
Poaceae) with the advantages of high cellulose yield, and high growth
even under low input and poor soil quality, has been identified as
a promising candidate for production of low-cost biofuels, papermaking,
and nanocellulose. In this study, 12 chemical pretreatments on a laboratory
scale were compared for different utilization purposes of switchgrass.
It was found that the pretreated switchgrass with sodium hydroxide
showed considerable potential for providing mixed sugars for fermentation
with 11.10% of residual lignin, 53.85% of residual cellulose, and
22.06% of residual hemicellulose. The pretreatment with 2.00% (v/v)
nitric acid was the best method to remove 78.37% of hemicellulose
and 39.82% of lignin under a low temperature (125 °C, 30 min),
which can be used in the production of nanocellulose. Besides, a completely
randomized design analysis of switchgrass pretreatments provided the
alternative ethanol organosolv delignification of switchgrass for
the papermaking industry with a high residual cellulose of 58.56%.
Finally, scanning electron microscopy (SEM), X-ray diffraction (XRD),
and Fourier-transform infrared spectroscopy (FT-IR) were carried out
to confirm the changes in functional groups, crystallinity, and thermal
behavior of the three materials, respectively, from the optimal pretreatments.