Activated carbon from vetiver roots: gas and liquid adsorption studies

Large quantities of lignocellulosic residues result from the industrial production of essential oil from vetiver grass (Vetiveria zizanioides) roots. These residues could be used for the production of activated carbon. The yield of char obtained after vetiver roots pyrolysis follows an equation recently developed [A. Ouensanga, L. Largitte, M.A. Arsene, The dependence of char yield on the amounts of components in precursors for pyrolysed tropical fruit stones and seeds, Micropor. Mesopor. Mater. 59 (2003) 85–91]. The N2 adsorption isotherm follows either the Freundlich law KFP which is the small equation limit of a Weibull shaped isotherm or the classical BET isotherm. The surface area of the activated carbons are determined using the BET method. The KF value is proportional to the BET surface area. The value increases slightly when the burn-off increases and also when there is a clear increase in the micropore distribution width