Ferrous Iron Oxidation under Varying pO2 Levels: The Effect of Fe(III)/Al(III) Oxide Minerals and Organic Matter
Abiotic Fe(II) oxidation by O2 commonly occurs in the presence of mineral sorbents and organic matter (OM) in soils and sediments; however, this tertiary system has rarely been studied. Therefore, we examined the impacts of mineral surfaces (goethite and γ-Al2O3) and organic matter [Suwannee River fulvic acid (SRFA)] on Fe(II) oxidation rates and the resulting Fe(III) (oxyhydr)oxides under 21 and 1% pO2 at pH 6. We tracked Fe dynamics by adding 57Fe(II) to 56Fe-labeled goethite and γ-Al2O3 and characterized the resulting solids using 57Fe Mössbauer spectroscopy. We found Fe(II) oxidation was slower at low pO2 and resulted in higher-crystallinity Fe(III) phases. Relative to oxidation of Fe(II)(aq) alone, both goethite and γ-Al2O3 surfaces increased Fe(II) oxidation rates regardless of pO2 levels, with goethite being the stronger catalyst. Goethite surfaces promoted the formation of crystalline goethite, while γ-Al2O3 favored nano/small particle or disordered goethite and some lepidocrocite; oxidation of Fe...
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Rohm and Haas Powder Coatings is delighted to announce that its Reading, Pennsylvania, facility is the first site in the world to receive the RCMS® Site Certification awarded by the American Chemical Council (ACC).
When Raj Gupta, Chairman and CEO of Rohm and Haas Company, became Chairman ... more