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Photo-Induced Reductive Dissolution of Hematite (α-Fe₂O₃) by S(IV) Oxyanions

Citation

Faust, Bruce Charles (1985) Photo-Induced Reductive Dissolution of Hematite (α-Fe₂O₃) by S(IV) Oxyanions. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/cj3r-5x15. https://resolver.caltech.edu/CaltechETD:etd-03262008-141334

Abstract

The kinetics and mechanism of the photo-induced reductive dissolution of hematite (α-Fe2O3) by S(IV) oxyanions, in aqueous suspensions of hematite, have been investigated. Experimental quantum yields for Fe(II)aq 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)aq.

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)aq from photo-induced ligand to metal charge transfer reactions of ≡Fe(III)-S(IV) surface complexes, ii) oxidation of Fe(II)aq to Fe(III)aq and, iii) the Fe(III)aq 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.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Environmental Engineering Science
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Environmental Science and Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Hoffmann, Michael R.
Thesis Committee:
  • Hoffmann, Michael R. (chair)
  • Morgan, James J.
  • Cass, Glen Rowan
  • Johnson, William Lewis
  • Seinfeld, John H.
Defense Date:2 October 1984
Funders:
Funding AgencyGrant Number
S. D. Bechtel, Jr. FoundationUNSPECIFIED
Environmental Protection Agency (EPA)UNSPECIFIED
Record Number:CaltechETD:etd-03262008-141334
Persistent URL:https://resolver.caltech.edu/CaltechETD:etd-03262008-141334
DOI:10.7907/cj3r-5x15
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1160
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:04 Apr 2008
Last Modified:19 Apr 2021 22:39

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