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 N 2 adsorption isotherm follows either the Freundlich law K FP α which is the small α 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 K F value is proportional to the BET surface area. The α value increases slightly when the burn-off increases and also when there is a clear increase in the micropore distribution width.