Sorption induced inhibition of redox reactions involving manganese oxides

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:560034

Fendorf, S; Jardine, P M; Brooks, S C ^[1]

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1. Univ. of Idaho, Moscow, ID (United States)

Manganese oxides are one of the most powerful oxidants in soils or sediments. Although being strong oxidants, their reactivity may be limited by surface coatings. We investigated the oxidation of Co(II)-EDTA{sup 2-} by {beta}-MnO{sub 2} in hydrodynamic systems and observed that the reaction was poisoned after a short initial reaction period. In order to determine surface alterations of the {beta}-MnO{sub 2} we used x-ray absorption spectroscopy (XAS) to probe the chemical and structural state of Mn. XAS was performed on porous columns of {beta}-MnO{sub 2} coated silica reacted with Co(II)-EDTA{sup 2-}. Upon exposure to a Co(II)-EDTA{sup 2-} solution, Mn(III) formed and remained on the {beta}-MnO{sub 2} surface in increasing proportions with time; Mn(II) was not observed. It therefore appears that retention of Mn(III)-oxides may thus be limited by the retention of redox reaction products on these materials.

• OSTI ID: 560034
• Report Number(s): CONF-970443--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
COATINGS
COBALT COMPOUNDS
EDTA
MANGANESE OXIDES
OXIDATION
REDOX REACTIONS