Characterization of biochar derived from rice husks and its potential in chlorobenzene degradation

The property of biochar and its potential application toward chlorobenzene degradation were investigated in this study. The biochar was derived from rice husk and charred at 550 °C in N2 atmosphere, which showed a significant degradation of chlorobenzene in ambient atmosphere. The results from Scanning Electron Microscope, X-Ray Diffraction and Raman Spectroscopy indicated the formation of poorly ordered graphene stacks embedded in amorphous phases on biochar. Fourier Transform Infrared Spectroscopy and Electron Paramagnetic Resonance suggested the existence of hydroquinone-quinone moieties on biochar, which could induce the generation of reactive oxygen species and promote the degradation of chlorobenzene. Furthermore, hydrogen peroxide and hydroxyl radicals were generated from the reduction of oxygen with the oxidization of phenolic hydroxyl groups on biochar, which was responsible for chlorobenzene degradation. In addition, more types of intermediate products of chlorobenzene degradation were detected in biochar system compared with conventional Fenton reaction, which could be possibly ascribed to the interfacial reaction between chlorobenzene and reactive oxygen species on biochar surface. The findings in this study would provide a new insight into the application of biochar in organic pollutant removal.