Journal ArticleDOI
Impact of Antimony(V) on Iron(II)-Catalyzed Ferrihydrite Transformation Pathways: A Novel Mineral Switch for Feroxyhyte Formation.
Kerstin Hockmann,Niloofar Karimian,Sara Schlagenhauff,Britta Planer-Friedrich,Edward D Burton +4 more
TLDR
In this paper, the authors investigated the impact of antimony on the Fe-II-induced transformation of ferrihydrite at pH 7 across a range of Sb(V) loadings (Sb:Fe(III) molar ratios of 0, 0.016, and 0.08).Abstract:
The environmental mobility of antimony (Sb) is controlled by interactions with iron (Fe) oxides, such as ferrihydrite. Under near-neutral pH conditions, Fe(II) catalyzes the transformation of ferrihydrite to more stable phases, thereby potentially altering the partitioning and speciation of associated Sb. Although largely unexplored, Sb itself may also influence ferrihydrite transformation pathways. Here, we investigated the impact of Sb on the Fe(II)-induced transformation of ferrihydrite at pH 7 across a range of Sb(V) loadings (Sb:Fe(III) molar ratios of 0, 0.003, 0.016, and 0.08). At low and medium Sb loadings, Fe(II) induced rapid transformation of ferrihydrite to goethite, with some lepidocrocite forming as an intermediate phase. In contrast, the highest Sb:Fe(III) ratio inhibited lepidocrocite formation, decreased the extent of goethite formation, and instead resulted in substantial formation of feroxyhyte, a rarely reported FeOOH polymorph. At all Sb loadings, the transformation of ferrihydrite was paralleled by a decrease in aqueous and phosphate-extractable Sb concentrations. Extended X-ray absorption fine structure spectroscopy showed that this Sb immobilization was attributable to incorporation of Sb into Fe(III) octahedral sites of the neo-formed minerals. Our results suggest that Fe oxide transformation pathways in Sb-contaminated systems may strongly differ from the well-known pathways under Sb-free conditions.read more
Citations
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Journal ArticleDOI
Mechanistic Study for Antimony Adsorption and Precipitation on Hematite Facets
TL;DR: In this paper , an extended X-ray absorption fine structure spectroscopy and density functional theory results provided a consensus on the local coordination environment of Sb (III) and Sb(V) on Fe2O3 facets.
Journal ArticleDOI
Mechanistic and modeling insights into the immobilization of Cd and organic carbon during abiotic transformation of ferrihydrite induced by Fe(II)
TL;DR: In this paper , the authors built a model for Cd species quantification during phase transformation based on mechanistic insights obtained from batch experiments and showed that adsorbed Cd was mainly controlled by FA and ferrihydrite, and direct complexation of Cd by FA had a strong impact on the continuous change in Cd at lower Fe(II) concentration.
Journal ArticleDOI
Antimonate Controls Manganese(II)-Induced Transformation of Birnessite at a Circumneutral pH
TL;DR: In this paper, different loadings of antimonate (herein termed Sb(V)) sorbed to birnessite determine the products formed during Mn(II)-induced transformation (at pH 7.5) and corresponding changes in Sb behavior.
Journal ArticleDOI
Antimony isotope fractionation during adsorption on aluminum oxides.
TL;DR: In this paper , the authors show that Sb(V) adsorption on γ-Al2O3 occurs via outer-sphere surface complexation and no significant equilibrium isotope fractionation (Δ123Sbaqueous-adsorbed = ~ 0 ± 0.08
Journal ArticleDOI
Iron Vacancy Accelerates Fe(II)-Induced Anoxic As(III) Oxidation Coupled to Iron Reduction.
TL;DR: In this article , the authors show that As(III) oxidation can be facilitated by Fe oxyhydroxides (i.e., goethite) under anoxic conditions coupled with the reduction of structural Fe(III).
References
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Journal ArticleDOI
ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT.
Bruce Ravel,Matthew Newville +1 more
TL;DR: A software package for the analysis of X-ray absorption spectroscopy (XAS) data is presented, based on the IFEFFIT library of numerical and XAS algorithms and is written in the Perl programming language using the Perl/Tk graphics toolkit.
Journal ArticleDOI
Antimony in the environment: a review focused on natural waters: II. Relevant solution chemistry
TL;DR: In this article, the main characteristics of the solution chemistry of antimony in relation to its behaviour and fate in natural waters are discussed based on a careful and systematic examination of a comprehensive collection of solution equilibrium and environmentally oriented studies, some published more than 100 years ago.
Journal ArticleDOI
Competing Fe (II)-induced mineralization pathways of ferrihydrite.
TL;DR: Predicting the secondary mineralization of ferrihydrite, a process having sweeping influences on contaminant/nutrient dynamics, will need to take into consideration kinetic restraints and transient precursor phases (e.g., lepidocrocite) that influence ensuing reaction pathways.
Journal ArticleDOI
Spectroscopic Evidence for Fe(II)−Fe(III) Electron Transfer at the Iron Oxide−Water Interface
TL;DR: Spectroscopic observations of Fe(II) reacted with oxide surfaces under conditions typical of natural environments suggest a novel pathway for the biogeochemical cycling of Fe and also raises important questions regarding the mechanism of contaminant reduction by Fe (II) in the presence of oxide surfaces.