IFIBA   22255
INSTITUTO DE FISICA DE BUENOS AIRES
Unidad Ejecutora - UE
artículos
Título:
Influence of the Al-for-Fe substitution in the adsorption of As(V) onto goethites-morphological surface characterization
Autor/es:
A.E.TUFO; MARIA CLAUDIA MARCHI; S.M.LANDI; M. DOS SANTOS AFONSO; E.E.SILEO
Revista:
Proceedings of the 5th International Congress on Arsenic in the Environment
Editorial:
CRC Press
Referencias:
Lugar: Londres; Año: 2014 vol. 1 p. 699 - 701
ISSN:
2154-6568
Resumen:
Arsenic
derived from natural and anthropogenic sources occurs in groundwater, and its
mobility is influenced by the presence of goethite and ferrihydrite, that
present a great affinity for As(V). As the substitution of Al for Fe in goethites is
well documented, in this
work we explore the adsorption of As(V) onto pure and Al-substituted goethites. We
have obtained the adsorption isotherm ([As]adsorbed vs. [As]solution)
and we found an uncommon bell shaped curve with a maximum at 0.25 mmolL-1,
after this value the adsorption decreased. In order to explore the possible
formation of FeAsO4 as a surface precipitate at [As]>0.25 mmolL-1,
we have obtained STEM micrographs of the As-adsorbed Al-goethites. The
micrographs indicated that no surface precipitates were formed. Based in this
results and PZC measurements we postulate that the decline in adsorption is
provoked by the formation of
bidentated complexes that decrease the adsorption
efficiency by coordinating to two metal sites.