Describing chlorophenol sorption on variable-charge
soil using the triple-layer model
Mara
Cea a, J.C. Seaman b, Alejandra A. Jara c,*,
M.L. Mora c, M.C. Diez d
a
Universidad de La Frontera, P.O. Box 54-D, Temuco, Chile
b Savannah River Ecology Laboratory, The University
of Georgia, Drawer E, Aiken, SC 29802, USA
c Departamento de Ciencias Químicas, Universidad de
La Frontera, P.O. Box 54-D, Temuco, Chile
d Departamento de Ingeniería Química, Universidad
de La Frontera, P.O. Box 54-D, Temuco, Chile
Abstract
The sorption of 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol
by a variable-charge soil from southern Chile was studied in a series
of batch experiments. The chlorophenol sorption behavior was evaluated
as a function of pH (pH range 4–8) at two different ionic strengths,
0.01 and 0.1 M KCl (25 °C). Chlorophenol sorption depended on pH and
a downward shift in the soil PZC was observed with increasing chlorophenol
concentration. Chlorophenol sorption decreased with increasing pH, suggesting
that the undissociated species is sorbed more readily and that electrostatic
repulsion may inhibit partitioning as pH increases. Data from the sorption
experiments were fitted by the triple-layer model, in which monodentate
outer- and inner-sphere complexes were formed between deprotonated organic
molecules and active sites on the variable-charge soil.
Keywords:
Variable charge soil; Chlorophenol; Surface complexation modeling
*
Corresponding author. Fax: +56 45 325053.
E-mail address: aljara@ufro.cl (A.A. Jara).
SREL
Reprint #2912
Cea, M., J. C. Seaman, A. A. Jara, M. L. Mora and M. C. Diez 2005. Describing chlorophenol sorption on variable-charge soil using the triple-layer model. Journal of Colloid and Interface Science 292:171-178.
