Oxidation of pyrite surfaces: a photoelectron spectroscopic study

Comparative XPS study between experimentally and naturally weathered pyrites

“…Furthermore, the bombardment resulted in the depletion of sulphur and the formation of a S 2À species centred at 161.3 eV. The peak centred at 531.7 eV could be definitely assigned to goethite [36], but the peak at 530.2 eV was difficult to assign: it could be assigned to either goethite [36] or ferric oxide [37]. Hence, it can at least be considered as indicating the presence of Fe 3+ -O.…”

“…) and most surface-sensitive species centred at 160.8 eV, to be continuously identified and reported [37,39,46,51,54,56,[58][59][60]. Following subsequent exposure to air, these most surficial species decreased in intensities and shifted to a higher energy binding [56].…”

The surface of enargite after exposure to acidic ferric solutions: an XPS/XAES study

“…The thickness of this layer was found to range between 0.13 and 0.36 nm after 30 min exposure to solution, corresponding to 0.25 to 0.67 monolayer coverage. 35 Thus, the authors suggest 'iron-deficient surface regions' as the correct terminology. In this work, after 24 h exposure in more aggressive acidic solutions, a layer of up to 0.7 nm was found ( Table 2).…”

“…A detailed study conducted by Karthe et al 35 showed that upon exposure of pyrite to air or neutral aqueous solutions. an iron-deficient sulfide species (binding energy at 163.9 eV) is formed at the surface.…”

Surface spectroscopic study of the adsorption of Ni(II) on pyrite and arsenopyrite at pH 10

“…The pristine pyrite surface has been observed only after cleavage under ultrahigh vacuum 9,10 or under drastic conditions. 11,12 Exposure to the ambient atmosphere or immersion in aqueous solution induces surface oxidation.…”