Journal article
Tooeleite Transformation and Coupled As(III) Mobilization Are Induced by Fe(II) under Anoxic, Circumneutral Conditions
Environmental science & technology, Vol.56(13), pp.9446-9452
23/06/2022
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Abstract
Tooeleite [FeIII6(AsIIIO3)4SO4(OH)4.4H2O] is an
important As(III) host phase in diverse mining-impacted environments. Tooeleite has also received attention as a target phase for
immobilizing As(III) in environmental and engineered settings.
However, little is known regarding tooeleite’s environmental
stability, with no previous research examining the possible role of
Fe(II) in inducing tooeleite transformation (as occurs for Fe(III)
oxide minerals). We investigated shifts in solid-phase Fe and As
speciation and associated As mobilization into the aqueous phase
during exposure of tooeleite to aqueous Fe(II) under anoxic
conditions at pH 4 to 8. Our results demonstrate that environmentally relevant concentrations of aqueous Fe(II) (i.e., 1 to 10
mM) induce significant mobilization of As(III) from tooeleite
under near-neutral pH conditions, with greater As(III) mobilization
occurring at higher pH. Extended X-ray absorption fine structure spectroscopy at both the As and Fe K-edge reveals that the
observed As(III) mobilization was coupled with partial Fe(II)-induced transformation of tooeleite to As(III)-bearing ferrihydrite at
pH 6 to 8. These results provide new insights into the environmental stability of tooeleite and demonstrate a novel pathway for
As(III) mobilization in tooeleite-bearing systems.
Details
- Title
- Tooeleite Transformation and Coupled As(III) Mobilization Are Induced by Fe(II) under Anoxic, Circumneutral Conditions
- Creators
- Girish ChoppalaDane LambRobert AughtersonEdward D Burton
- Publication Details
- Environmental science & technology, Vol.56(13), pp.9446-9452
- Comment
- Arsenic and Fe solid-phase speciation work were carried out on the XAS beamline with the support of Dr. Jessica Hamilton at the Australian Synchrotron. Southern Cross GeoScience is acknowledged for providing glovebox facilities. We thank Dr. CI Sathish (Global Innovative Centre for Advanced Nanomaterials, University of Newcastle) for support in SEM–EDX analyses.
- Grant note
- Funding was supported by the Australian Research Council (ARC) (IN190100044). E.D.B. was supported by a Future Fellowship from the Australian Research Council (FT200100449). X-ray Absorption Spectroscopy (XAS) analyses at the Australian Synchrotron (Melbourne) was supported by the Australian Nuclear Science and Technology Organization (ANSTO) (AS211/XAS/16852; AS211/XAS/16853). Transmission Emission Microscopy studies were supported by ANSTO (Sydney) (AP13130).
- Identifiers
- 991013033085502368
- Copyright
- © 2022 American Chemical Society
- Academic Unit
- Faculty of Science and Engineering; Science
- Language
- English
- Resource Type
- Journal article