SREL Reprint #3017

Adsorption behavior of 2,4-dichlorophenol and pentachlorophenol in an allophanic soil

Mara Cea1, J.C. Seaman2, Alejandra A. Jara3, Bárbara Fuentes4, M.L. Mora3, and M.C. Diez1

1Department of Chemical Engineering, University of La Frontera, P.O. Box 54-D, Temuco, Chile
2The University of Georgia, Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, United States
3Department of Chemical Science, University of La Frontera, P.O. Box 54-D, Temuco, Chile
4Doctorado en Ciencias de Recursos Naturales, University of La Frontera, P.O. Box 54-D, Temuco, Chile

Abstract: The adsorption of 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP) by a variable-charge soil from southern Chile was studied in a series of batch equilibration experiments. 2,4-DCP and PCP adsorption behavior was evaluated as a function of pH (pH values of 4.5, 6.0 and 7.5) in a 0.1 M KCl (25 °C) background solution for soil material collected at three different depths (0-20 cm, 20-40 cm, and 40-60 cm). 2,4-DCP and PCP adsorption decreased with increasing soil pH, suggesting that the undissociated species were adsorbed more readily and that electrostatic repulsion may inhibit partitioning as pH increases. The PCP adsorption was greater than observed for 2,4-DCP and decreased with soil depth. Multiple regression analysis between Kd and various soil properties indicated that the soil organic carbon content is a strong indicator of chlorophenol adsorption, and in addition to organic carbon, the soil pH is an important property controlling adsorption behavior.

Keywords: Variable-charge soil; Allophane; Andisol; Adsorption; Hydrophobic partitioning; 2,4-Dichlorophenol; Pentachlorophenol

SREL Reprint #3017

Cea, M., J. C. Seaman, A. A. Jara, B. Fuentes, M. L. Mora and M. C. Diez. 2007. Adsorption behavior of 2,4-dichlorophenol and pentachlorophenol in an allophanic soil. Chemosphere 67(7): 1354-1360.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).