Journal article
Inhibition of trace element release during Fe(II)-activated recrystallization of Al-, Cr-, and Sn-substituted goethite and hematite
Environmental science & technology, Vol.46(18), pp.10031-10039
09/18/2012
DOI: 10.1021/es302137d
PMID: 22924460
Abstract
Aqueous Fe(II) reacts with Fe(III) oxides by coupled electron transfer and atom exchange (ETAE) resulting in mineral recrystallization, contaminant reduction, and trace element cycling. Previous studies of Fe(II)-Fe(III) ETAE have explored the reactivity of either pure iron oxide phases or those containing small quantities of soluble trace elements. Naturally occurring iron oxides, however, contain substantial quantities of insoluble impurities (e.g., Al) which are known to affect the chemical properties of such minerals. Here we explore the effect of Al(III), Cr(III), and Sn(IV) substitution (1-8 mol %) on trace element release from Ni(II)-substituted goethite and Zn(II)-substituted hematite during reaction with aqueous Fe(II). Fe(II)-activated trace element release is substantially inhibited from both minerals when an insoluble element is cosubstituted into the structure, and the total amount of release decreases exponentially with increasing cosubstituent. The limited changes in surface composition that occur following reaction with Fe(II) indicate that Al, Cr, and Sn do not exsolve from the structure and that Ni and Zn released to solution originate primarily from the bulk rather than the particle exterior (upper ~3 nm). Incorporation of Al into goethite substantially decreases the amount of iron atom exchange with aqueous Fe(II) and, consequently, the amount of Ni release from the structure. This implies that trace element release inhibition caused by substituting insoluble elements results from a decrease in the amount of mineral recrystallization. These results suggest that naturally occurring iron oxides containing insoluble elements are less susceptible to Fe(II)-activated recrystallization and exhibit a greater retention of trace elements and contaminants than pure mineral phases.
Details
- Title: Subtitle
- Inhibition of trace element release during Fe(II)-activated recrystallization of Al-, Cr-, and Sn-substituted goethite and hematite
- Creators
- Andrew J Frierdich - Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130, United States. frierdich@wisc.eduMichelle M SchererJonathan E BachmanMark H EngelhardBrett W RapponottiJeffrey G Catalano
- Resource Type
- Journal article
- Publication Details
- Environmental science & technology, Vol.46(18), pp.10031-10039
- Publisher
- United States
- DOI
- 10.1021/es302137d
- PMID
- 22924460
- ISSN
- 0013-936X
- eISSN
- 1520-5851
- Language
- English
- Date published
- 09/18/2012
- Academic Unit
- Civil and Environmental Engineering
- Record Identifier
- 9983992049602771
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