Photo-induced reductive dissolution of hematite ([alpha]-Fe2O3) by S(IV) oxyanions

Citation

Faust, Bruce Charles (1985) Photo-induced reductive dissolution of hematite ([alpha]-Fe2O3) by S(IV) oxyanions. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-03262008-141334

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.

The kinetics and mechanism of the photo-induced reductive dissolution of hematite ([alpha]-Fe2O3) by S(IV) oxyanions, in aqueous suspensions of hematite, have been investigated. Experimental quantum yields for Fe(II)[...] production are reported for deoxygenated hematite suspensions containing S(IV). Quantum yield studies together with spectroscopic information indicate that [...]Fe(III)—S(IV) surface complexes undergo a photo-induced ligand to metal charge transfer reaction resulting in the reductive dissolution of hematite and production of Fe(II)[...].

The autoxidation of S(IV) in oxygenated hematite suspensions exhibits autocatalytic behavior. This behavior is interpreted in terms of three general processes: i) production of Fe(II)[...] from photo-induced ligand to metal charge transfer reactions of [...]Fe(I11)--S(IV) surface complexes, ii) oxidation of Fe(II)[...] to Fe(III)[...] and, iii) the Fe(III)[...] catalyzed autoxidation of S(IV). A numerical model, based on these processes, is developed to predict the disappearance of S(IV) in oxygenated hematite suspensions under illumination.

Thesis Files