Herein, we aimed to determine the physicochemical properties of biochar produced from rice husk at 350 and 5508C, to characterize changes in the biochar properties during aging and to identify the effect of aging time on these changes. To simulate different stages in the aging process, samples were incubated at a constant temperature in the dark and maintained at 60% water holding capacity for 100-300 d. The transformation and morphology of the biochar particles were monitored by diffuse-reflectance Fourier transform infrared spectroscopy (DRIFTS), scanning electron microscopy (SEM) coupled with energy X-ray dispersive spectroscopy, and X-ray photoelectron spectroscopy (XPS). During aging, a layer formed on the surface and the content of easily oxidized substances increased with increased aging time. In addition, SEM indicated that oxidation occurred close to the biochar surface rather than in the biochar particle interior. Furthermore, the DRIFTS and XPS results indicated that the biochar surface produced at 5508C underwent decarboxylation and hydroxylation, while for the 3508C biochar, the increase in surface oxygen content was associated with the presence of hydroxyl moieties.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.