INVESTIGADORES
AURELIO Gabriela
congresos y reuniones científicas
Título:
Co-precipitation of As (III/V) and Se (IV/VI) with calcite
Autor/es:
G. ROMAN-ROSS; G. AURELIO; A. FERNANDEZ MARTINEZ; L. CHARLET; G. J. CUELLO; F. BARDELLI
Lugar:
Varsovia, Polonia
Reunión:
Conferencia; E-MRS Fall Meeting 2007; 2007
Institución organizadora:
European Materials Research Society
Resumen:
The study of the adsorption of contaminants in soils is a very active area of research in
the fields of geochemistry and soil physical-chemistry. Some important constituents of
soils, like clays, iron oxides, carbonates or sulfate minerals are of particular interest
because their capacity to adsorb elements that are potentially risky for the environment,
in the form of cations or oxyanions.
Carbonates are present in many near-surface environments. Specifically, calcite is a very
abundant mineral and so its fundamental importance in many fields, related to
immobilization of both inorganic and organic species. For this reason, ion incorporation in
the structure of carbonate minerals is a subject of major concern, as well as the
nanoscale mechanisms by which the ions are exchanged or substituted. In this context,
co-precipitation is the most important mechanism by which an ion can get trapped into
the bulk of a mineral, retarding its transport and subsequent availability to the
environment.
In this work we present a systematic study of synthetic calcite samples co-precipitated
with As(III), As(V), Se(IV) and Se(VI), to understand the sites and mechanisms of
incorporation of their oxyanions. Combining spectroscopic (Neutron and X-ray
Diffraction, EXAFS) and modeling (DFT) techniques, we probe the bulk minerals and gain
insight into the substitution processes that take. Simulations help us to understand and
predict which sites within the structure of the mineral would be more favorable for the
substitution to occur.
The precise knowledge of the concentration of substituted As or Se in the bulk of the
minerals is very important to predict the fate of these ions upon its release to the
environment.