Surface Structures and Stability of Arsenic(III) on Goethite: Spectroscopic Evidence for Inner-Sphere Complexes

摘要: The adsorption and stability of arsenite [As(III)] on goethite (α-FeOOH) was investigated using a combination standard batch techniques X-ray absorption spectroscopy (XAS). reactivity As(III) with α-FeOOH at varying pH concentration provided macroscopic evidence for strong complexation the surface. Extended fine structure (EXAFS) gave an average As(III)−Fe interatomic distance 3.378 ± 0.014 A, which is indicative bidentate binuclear bridging complexes surface similar to other oxyanions adsorb by inner-sphere mechanism. near-edge (XANES) analysis indicated that As(III)−α-FeOOH complex stable toward heterogeneous oxidation As(V), as determined energy position edge. structural information from EXAFS included in description complexation...