Organosolv fractionation is a promising approach for the separation
of lignocellulosic components in integrated biorefineries where each
component can be fully valorized into valuable platform chemicals
and biofuels. In this study, microwave-accelerated organosolv fractionation
was developed for the modification of lignocellulosic fractionation
of rice husk. The fractionation condition was optimized for 1 h with
the microwave irradiation at 300 W using a ternary solvent mixture
composed of 24%:32%:44% water/ethanol/methyl isobutyl ketone. The
effects of mineral acids (HCl, H3PO4, and H2SO4) and heterogeneous acid promoters (HCl, H3PO4, and H2SO4 impregnated
over activated carbon) on the efficiency and selectivity of product
yields (i.e., glucan, hemicellulose-derived products, and lignin)
were also investigated. It was found that the use of H3PO4–activated carbon as the promoter showed superior
performance on the fractionation of rice husk components, resulting
in 88.8% recovery of cellulose, with 63.8% purity in the solid phase,
whereas the recovery of hemicellulose (66.4%) with the lowest formation
of furan and 5-hydroxymethyl furfural and lignin (81.0%) without sugar
cross-contamination was obtained in the aqueous ethanol phase and
organic phase, respectively. In addition, the morphology structure
of fractionated rice husk presented 2.6-fold higher surface area (5.4
m2/g) of cellulose-enriched fraction in comparison with
the native rice husk (2.1 m2/g), indicating the improvement
of enzyme accessibility. Besides, the chemical changes of isolated
lignin were also investigated by Fourier-transform infrared spectroscopy.
This work gives pieces of information into the efficiencies of the
microwave strategy as a climate neighborly elective fractionation
method for this serious starting material in the biotreatment facility
business.