Reductive dissolution of iron(III) (hydr)oxides by hydrogen sulfide

The reductive dissolution of hematite by H2S was investigated under conditions of constant partial pressure of H2S (10-4 to 10-2 atm), pH = 3-7 and 25°C, and under conditions where the solubility product of iron sulfide is not exceeded. The reaction proceeds by an initial (relatively fast) formation...

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Detalles Bibliográficos
Autor principal: Dos Santos Afonso, M.
Otros Autores: Stumm, W.
Formato: Capítulo de libro
Lenguaje:Inglés
Publicado: 1992
Acceso en línea:Registro en Scopus
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Registro en la Biblioteca Digital
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100 1 |a Dos Santos Afonso, M. 
245 1 0 |a Reductive dissolution of iron(III) (hydr)oxides by hydrogen sulfide 
260 |c 1992 
270 1 0 |m Dos Santos Afonso, M.; Depto de Química Inorgánica, Analítica y Química Física, Ciudad Universitaria Pabellón II, 1428 Buenos Aires, Argentina 
506 |2 openaire  |e Política editorial 
520 3 |a The reductive dissolution of hematite by H2S was investigated under conditions of constant partial pressure of H2S (10-4 to 10-2 atm), pH = 3-7 and 25°C, and under conditions where the solubility product of iron sulfide is not exceeded. The reaction proceeds by an initial (relatively fast) formation of ≡FeS- and ≡FeSH surface complexes; subsequently, electron transfer and detachment of Fe(II) from the oxide surface occur. The rate law for the dissolution can be interpreted by assuming a surface-controlled reaction depending on the surface concentration of the surface complexes ≡FeS- and ≡FeSH: Rt = ke{≡FeS-} + ke′{≡FeSH} where {≡FeS-} and {≡FeSH} are surface concentrations in mol·m-2. The experimental data are compatible with the constants ke = 30 h-1 and ke′ = 400 h-1 and surface complex formation constants for ≡FeS- (≡FeOH + H2S(g) ⇄ ≡FeS- + H+ + H2O) and ≡FeSH (≡FeOH + H2S(g) ⇄ ≡FeSH + H2O) of log Ks = -2.70 and 2.82, respectively. Preliminary experiments with lepidocrocite and goethite give results on the reaction rates that show the same kind of dependence on solution variables as those with α-Fe2O3 and are compatible with the mechanism proposed here. © 1992 American Chemical Society.  |l eng 
593 |a Swiss Federal Institute for Water Resources and Water Pollution Control (EAWAG), Swiss Federal Institute of Technology (ETH), Duebendorf, Switzerland 
593 |a Depto de Química Inorgánica, Analítica y Química Física, Ciudad Universitaria Pabellón II, 1428 Buenos Aires, Argentina 
700 1 |a Stumm, W. 
773 0 |d 1992  |g v. 8  |h pp. 1671-1675  |k n. 6  |x 07437463  |t Langmuir 
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