Differential sorption behaviour of aromatic hydrocarbons on.pdf

/locate/chemosphere Chemosphere 67 (2007) 1033–1042Differential sorption behaviour of aromatic hydrocarbons on charcoals prepared at different temperatures from grass and wood Ludger C. Bornemann a,b,*,1, Rai S. Kookana a, Gerhard Welp b a CSIRO Land and Water, Adelaide Laboratory, Waite Road, Urrbrae SA, Australia b Institute of Crop Science and Resource Conservation of the University of Bonn, Division of Soil Science, Nussallee 13, 53115 Bonn, Germany Received 27 June 2006; received in revised form 13 October 2006; accepted 19 October 2006 Available online 8 December 2006 In memory of the 100th anniversary of the birth of Prof. Dr. H.C. Eduard Mu?ckenhausen (February 17th 1907)Abstract Naturally occurring charcoals are increasingly being recognized as effective sorbents for organic compounds. In this study we inves- tigated the sorption of benzene and toluene in single-sorbate and bi-sorbate systems on different types of charcoals produced in labora- tory, employing the batch sorption technique. Air dried plant materials from Phalaris grass (Phalaris tuberosa) and Red Gum wood (Eucalyptus camadulensis) were combusted under limited oxygen supply at 250 C, 450 C, and 850 C. The resulting charcoals were char- acterized for their specific surface areas, total cation content, and pore size distributions (pore size distribution only for wood combusted at 450 C and 850 C). For the materials treated at 850 C not only the surface area, microporosity, and total amount of sorbed sorbate increased markedly, but also the non-linearity of the sorption isotherm. The pore size distributions and surface areas as well as an indif- ferent sorption behaviour and competition effects for both sorbates indicated that pore filling mechanisms were the dominating processes governing the sorption on these microporous, high temperature treated materials. For the materials treated at lower temperatures the affinity of toluene was higher compared to that of benzene. In the bi-sorbate sys