Study of chemical activation process of a lignocellulosic material with KOH by XPS and XRD

Chemical activation of carbons is currently a very common method for obtaining activated carbons with very high surface areas. KOH is one of the most effective agents employed for this purpose. However, the reaction mechanism of this kind of activation it is not yet completely elucidated, although some models have been proposed. In this paper, an activated charcoal was obtained from a lignocellulosic material by impregnation with different amounts of KOH. The activation process was studied by X-ray photoelectron spectroscopy and X-ray diffraction. These techniques point to the formation of different potassium compounds at the carbon surface (mainly K2CO3 and different oxides) and show the dependence between surface area development in the carbons and the amount of K2CO3 formed during the activation process. (C) 2003 Elsevier Science Inc. All rights reserved.