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Título : | Analysis of anion adsorption effects on alumina nanoparticles stability |
Autor : | Missana, Tiziana Benedicto, Ana Mayordomo, Natalia Alonso, Ursula |
Palabras clave : | Nanoparticles Stability Alumina Anions |
Fecha de publicación : | abr-2014 |
Editorial : | ELSEVIER |
Citación : | Tiziana Missana, Ana Benedicto, Natalia Mayordomo, Ursula Alonso, Analysis of anion adsorption effects on alumina nanoparticles stability, Applied Geochemistry 49 (2014) 68–76. |
Resumen : | Nanoparticles and colloids can be relevant in contaminant migration if the contaminant is strongly adsorbed onto the particles and they are stable and mobile. The main conditions required for a colloidal
system to be considered as ‘‘stable’’ are: (1) low ionic strength of the groundwater (<1 · 10-3 M) and (2)
pH far from the point of zero charge (pHPZC). These conditions however, are too simplified to describe the
colloidal behaviour in real cases; in fact, specific adsorption of different ions may also have an important
impact on colloid stability.
In particular, in this study we analyse the effects of the adsorption of inorganic anions on Al2O3 oxide
nanoparticles (alumina NPs) stability, combining batch adsorption studies with electrophoretic and
dynamic light scattering measurements. Selenite adsorption was studied in a wide range of pHs (3–11), ionic strengths (5 · 10-4 – 1 · 10-1 M) and selenite concentration. Different electrolytes were used
to understand the competitive effects for selenite sorption of different anions in solution (ClO4-
, NO3-, HCO3-, SO42-) and especially their overall influence on alumina NPs stability.
The positive charge of alumina, under acid and neutral-alkaline pHs, favours anion adsorption which, in turn, may result in a decrease of the net surface charge, promoting particle aggregation and the destabilisation
of the system. Results showed that, the higher the anion affinity for alumina surface and sites
occupancy, the higher the destabilisation of particles. The sorption selectivity observed in our study
was: SeO3 2- > SO42- > HCO3- > NO3- > ClO4-.
Upon anion adsorption, particles aggregation was evident, but a clear change in z-potential, was only
observed with very high surface occupancies. Surface complexation modelling has been shown to be useful supporting tool for stability studies. |
URI : | http://dx.doi.org/10.1016/j.apgeochem.2014.04.003 http://documenta.ciemat.es/handle/123456789/3285 |
Aparece en las colecciones: | Artículos de Fisión Nuclear
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