XAFS Studies of Pb(II)-Chloro and Hg(II)-Chloro Ternary Complexes on Goethite

J. Bargar , P. Persson , G. Brown

EXAFS spectroscopy was used to study Pb(II) and Hg(II) adsorption complexes on goethite (α-FeOOH) in the presence of Cl-. At pH 7, the dominant Pb(II) species are bonded to edges of FeO6 octahedra and are similar to complexes that occur in the absence of Cl-. At pH≤6, Pb(II)-chloro ternary complexes pedominate and are bonded to corners of FeO6 octahedra. At pH 6.5, linear Hg(OH)Cl ternary complexes predominate that are bonded to goethite through surface oxygens in a bent Hg-O-Fe geometry. In the absence of Cl-, the Hg(II) surface complexes retain this basic geometry, but an OH group replaces the chloride ion in the first coordination shell.

Domaines: Articles anciens

J. Bargar, P. Persson, G. Brown. XAFS Studies of Pb(II)-Chloro and Hg(II)-Chloro Ternary Complexes on Goethite. Journal de Physique IV Proceedings, 1997, 7 (C2), pp.C2-825-C2-826. ⟨10.1051/jp4:1997249⟩. ⟨jpa-00255328⟩