Structural evaluation of sugar cane bagasse steam pretreated in the presence of CO2 and SO2

The SEM, TEM, XRD and FTIR spectroscopy techniques used in this work contributed to structural and chemical analysis of the untreated and pretreated bagasse. The images from SEM and TEM can be related to the severity of SO2 pretreatment, which is almost twice higher. The crystallinity index values obtained from XRD showed that pretreated materials have higher values when compared with untreated material, due to the partial removal of hemicellulose after pretreatment. FTIR spectroscopy supported SEM, TEM and XRD results. CO2 can actually be used as impregnating agent for steam pretreatment, although the present study confirmed a more extensive action of SO2.