info:eu-repo/semantics/article
Modeling the acid-base surface properties of aquatic sediments
Fecha
2010-03Registro en:
Borgnino Bianchi, Laura Carolina; Garcia, Maria Gabriela; Hidalgo, Margarita del Valle; Avena, Marcelo Javier; de Pauli, Carlos Primo; et al.; Modeling the acid-base surface properties of aquatic sediments; Springer; Aquatic Geochemistry; 16; 2; 3-2010; 279-291
1380-6165
1573-1421
CONICET Digital
CONICET
Autor
Borgnino Bianchi, Laura Carolina
Garcia, Maria Gabriela
Hidalgo, Margarita del Valle
Avena, Marcelo Javier
de Pauli, Carlos Primo
Blesa, Miguel Angel
Depetris Gallino, Pedro Jose
Resumen
We propose a model that explains the acid-base surface properties of clastic sediments from two Argentinean reservoir lakes. The model uses potentiometric titration data sets and fixed parameters such as the apparent stability constants and reaction stoichiometries of acid-base equilibriums involving known mineral phases. The model considers that sediments act as a set of independent sorption surfaces, such as organic matter, clay silicate, and iron (hydr)oxides, thus the acid-base equilibrium and the correspondent protolytic constants are represented by a humic acid, a Na-illite, and a poor crystalline Fe-hydr(oxide). In agreement with experimental data, the model predicts that all sediment samples show a similar charging behavior, increasing the negative charge as the pH increases. The net charge of sediments is controlled by the presence of negatively charged minerals and/or organic matter coatings. This reveals the great influence of clays and organic matter functional groups on the acid-base surface properties of sediments, and consequently on the surface reactivity toward contaminant transport. © 2009 Springer Science+Business Media B.V.