Reactivity at (nano)particle-water interfaces, redox processes, and arsenic transport in the environment.

Laurent Charlet (1) , Guillaume Morin (2) , Jérôme Rose (3) , Yuheng Wang (2) , Melanie Auffan (3) , André Burnol (4, 5) , Alejandro Fernandez-Martinez (1)

1 Géochimie
2 IMPMC - Institut de minéralogie et de physique des milieux condensés
3 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement
4 ISTerre - Institut des Sciences de la Terre
5 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

Massive deleterious impacts to human health are resulting from the use of arsenic-bearing groundwaters in South-East Asia deltas and elsewhere in the world for drinking, cooking and/or irrigation. In Bangladesh alone, a fifth of all deaths are linked to arsenicosis. In the natural and engineered subsurface environment, the fate of arsenic is, to a large extent, controlled by redox potential, pH, as well as total iron, sulfur and carbonate content, via sorption and coprecipitation on a variety of natural and engineered (nano)particles. In the present article, we address: (1) new insights in the sorption mechanisms of As on Fe(II) and Fe(III) nanophases recognized to play an important role in the microbial cycling of As and Fe; (2) artifacts often encountered in field and laboratory studies of As speciation due to the extreme redox sensitivity of the Fe-As-O-H phases; and (3) as a conclusion, the implications for water treatment. Indeed the specific reactivity of nanoparticles accounts not only for the As bioavailability within soils and aquifers, but also opens new avenues in water treatment.

Keywords: Arsenic; Aquifers; Bioavailability; Water treatment; Speciation; Adsorption; Experimental artifacts; Molecular mechanism; XAFS spectroscopy; Molecular dynamics

Domains: Geochemistry; Mineralogy; Continental interfaces, environment; Global Changes

Laurent Charlet, Guillaume Morin, Jérôme Rose, Yuheng Wang, Melanie Auffan, et al.. Reactivity at (nano)particle-water interfaces, redox processes, and arsenic transport in the environment.. Comptes Rendus Géoscience, 2011, 343 (2-3), pp.123-139. ⟨10.1016/j.crte.2010.11.005⟩. ⟨hal-00593239⟩