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Article Dans Une Revue Geochimica et Cosmochimica Acta Année : 2005

Natural manganese oxide: Combined analytical approach for solid characterization and arsenic retention

Résumé

To understand the retention of As on a natural manganese sand, the structural, textural and chemical properties of the solid were first investigated by combining scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron-energy-loss spectroscopy (EELS), X-ray diffraction (XRD), BET N2 gas adsorption, diffuse reflectance Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis. Manganese sand could be mainly described as a mixture of a phyllomanganate, lithiophorite [(Al,Li)MnO2(OH)2], and pyrolusite (MnO2). Iron particle, kaolinite and gibbsite type-phases were also observed. Particles organization led to the presence of a mesoporosity with pore diameters ranging from 100 to 200 Å and a specific surface area of 23 m2 g−1. Contact with an As(V) solution (0.67 mmol L−1) led to an average fractional surface coverage of 0.4. Both As (V) and (III) were present on the surface of the sand in a 1:1 ratio. As(V) was sorbed on lithiophorite-type particles through surface complexation type reaction. As(III) was thought to result from As(V) reduction mechanism on iron particles.

Dates et versions

hal-01486358 , version 1 (09-03-2017)

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Stéphanie Ouvrard, Philippe de Donato, Marie-Odile Simonnot, Sylvie Begin, Jaafar Ghanbaja, et al.. Natural manganese oxide: Combined analytical approach for solid characterization and arsenic retention. Geochimica et Cosmochimica Acta, 2005, 69 (11), pp.2715-2724. ⟨10.1016/j.gca.2004.12.023⟩. ⟨hal-01486358⟩
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