Characterization of soil particles by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and transmission electron microscopy (TEM)

Karine Flogeac , Emmanuel Guillon , Michel Aplincourt , Eric Marceau , Lorenzo Stievano , Patricia Beaunier , Yves-Michel Frapart

Knowledge of the structure and composition of the solid phases of a soil is needed to understand the retention mechanisms of transition metals or organic pollutants on the molecular scale. With this aim, the characterization of a soil sample from the Champagne-Ardenne region was carried out using various non-destructive methods such as X-ray diffraction (XRD), transmission electron microscopy-energy dispersive X-ray spectrometry (TEM-EDX), Mössbauer and electron paramagnetic resonance (EPR) spectroscopies, X-ray photoelectron spectroscopy (XPS), and protometric studies. The combination of these techniques allowed us to obtain a precise knowledge of the solid structure and composition. We showed that soil particles consist of quartz, alumino-silicate and goethite which are partially covered by organic matter. XPS spectra showed that organic matter is preferentially coated onto an alumino-silicate surface. EPR spectroscopy revealed the presence of unexpected vanadyl moieties in the organic matter. Acid-base titrations provided information on available surface sites (0.25 mmol ¥ g-1, i.e. 2.25 sites per nm2), and the point of zero charge pHzpc (3.9).

Mots clés: XRD; TEM-EDX; EPR; XPS; surface sites; soil

Domaines: Sciences agricoles; Ecologie, Environnement

Karine Flogeac, Emmanuel Guillon, Michel Aplincourt, Eric Marceau, Lorenzo Stievano, et al.. Characterization of soil particles by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and transmission electron microscopy (TEM). Agronomy for Sustainable Development, 2005, 25 (3), pp.345-353. ⟨hal-00886300⟩