XRD evaluation of KOH activation process and influence of coal rank

Three Japanese coals with different rank (Ohmine, Miike and Taiheiyo coals) were activated with KOH from 300 to 850°C. Higher rank coal with lower oxygen content showed a high yield and also a large specific surface area determined by N2 adsorption isotherms. X-ray diffraction (XRD) patterns of the activated carbons were measured to characterize stacking structure of aromatic layers by standardized analysis of coal by XRD method, considering the presence of slit-shaped micropores among the stacking structure. Structural parameters obtained by this method were related to the yield and the surface area in order to discuss the feature of micropores developed during the activation.