Metal (Fe, Cu, and As) transformation and association within secondary minerals in neutralized acid mine drainage characterized using X-ray absorption spectroscopy

Ye, Zhihang; Zhou, Jianwei; Liao, Peng; Finfrock, Y. Zou; Liu, Yingying; Cheng, Sheng; Liu, Peng

doi:10.1016/j.apgeochem.2022.105242

Cited by 34 publications

(14 citation statements)

References 59 publications

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“…The fitting was employed to obtain the CNs, Δ E 0 , f , σ 2 , Δ R , and goodness of fit ( R -factor). Detailed methods with respect to sample preparation, beamline instrumentation and setup, and methods of data collection and fitting results evaluation are provided in the SI and previous studies. , …”

Section: Methodsmentioning

confidence: 99%

“…Detailed methods with respect to sample preparation, beamline instrumentation and setup, and methods of data collection and fitting results evaluation are provided in the SI and previous studies. 36,37 Sb Isotope Analysis by MC-ICP-MS. Sb isotope samples were collected during the kinetic, isothermal, and adsorption edge experiments and subjected to isotope separation and purification methods mainly based on previous reports. 20 Ion exchange chromatography combined with a thiol resin column was used for the separation and purification of Sb isotopes.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Antimony Isotope Fractionation Revealed from EXAFS during Adsorption on Fe (Oxyhydr)oxides

Zhou

Feng

et al. 2023

Environ. Sci. Technol.

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A lack of knowledge about antimony (Sb) isotope fractionation mechanisms in key geochemical processes has limited its environmental applications as a tracer. Naturally widespread iron (Fe) (oxyhydr)oxides play a key role in Sb migration due to strong adsorption, but the behavior and mechanisms of Sb isotopic fractionation on Fe (oxyhydr)oxides are still unclear. Here, we investigate the adsorption mechanisms of Sb on ferrihydrite (Fh), goethite (Goe), and hematite (Hem) using extended X-ray absorption fine structure (EXAFS) and show that inner-sphere complexation of Sb species with Fe (oxyhydr)oxides occurs independent of pH and surface coverage. Lighter Sb isotopes are preferentially enriched on Fe (oxyhydr)oxides due to isotopic equilibrium fractionation, with neither surface coverage nor pH influencing the degree of fractionation (Δ123Sbaqueous‑adsorbed). Limited Fe atoms are present in the second shell of Hem and Goe, resulting in weaker surface complexes and leading to greater Sb isotopic fractionation than with Fh (Δ123Sbaqueous‑adsorbed of 0.49 ± 0.004, 1.12 ± 0.006, and 1.14 ± 0.05‰ for Fh, Hem, and Goe, respectively). These results improve the understanding of the mechanism of Sb adsorption by Fe (oxyhydr)oxides and further clarify the Sb isotope fractionation mechanism, providing an essential basis for future application of Sb isotopes in source and process tracing.

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Section: Methodsmentioning

confidence: 99%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Antimony Isotope Fractionation Revealed from EXAFS during Adsorption on Fe (Oxyhydr)oxides

Zhou

Feng

et al. 2023

Environ. Sci. Technol.

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“…The E0 of the reference minerals involved in the fitting was set to 7128 eV. More details are provided in our previous study. , …”

Section: Methodsmentioning

confidence: 99%

“…More details are provided in our previous study. 26,27 Fortran-based HAMA code was used for the wavelet transform (WT) analysis of k 3 -weighted EXAFS spectra; the details are given in Text S6. We selected data between R + ΔR (Fe) = 2.0 and 4.0 Å for qualitative research and adjusted the resolution of the signal by changing the values of parameters n and σ to distinguish the contributions of different atoms at different positions.…”

Section: Exafs Experiments and Datamentioning

confidence: 99%

Atomic-Level Structural Differences between Fe(III) Coprecipitates Generated by the Addition of Fe(III) Coagulants and by the Oxidation of Fe(II) Coagulants Determine Their Coagulation Behavior in Phosphate and DOM Removal

Yang

Graham

Liu

et al. 2023

Environ. Sci. Technol.

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In situ Fe(III) coprecipitation from Fe2+ oxidation is a widespread phenomenon in natural environments and water treatment processes. Studies have shown the superiority of in situ Fe(III) (formed by in situ oxidation of a Fe(II) coagulant) over ex situ Fe(III) (using a Fe(III) coagulant directly) in coagulation, but the reasons remain unclear due to the uncertain nature of amorphous structures. Here, we utilized an in situ Fe(III) coagulation process, oxidizing the Fe(II) coagulant by potassium permanganate (KMnO4), to treat phosphate-containing surface water and analyzed differences between in situ and ex situ Fe(III) coagulation in phosphate removal, dissolved organic matter (DOM) removal, and floc growth. Compared to ex situ Fe(III), flocs formed by the natural oxidizing Fe2+ coagulant exhibited more effective phosphate removal. Furthermore, in situ Fe(III) formed through accelerated oxidation by KMnO4 demonstrated improved flocculation behavior and enhanced removal of specific types of DOM by forming a more stable structure while still maintaining effective phosphate removal. Fe K-edge extended X-ray absorption fine structure spectra (EXAFS) of the flocs explained their differences. A short-range ordered strengite-like structure (corner-linked PO4 tetrahedra to FeO6 octahedra) was the key to more effective phosphorus removal of in situ Fe(III) than ex situ Fe(III) and was well preserved when KMnO4 accelerated in situ Fe(III) formation. Conversely, KMnO4 significantly inhibited the edge and corner coordination between FeO6 octahedra and altered the floc-chain-forming behavior by accelerating hydrolysis, resulting in a more dispersed monomeric structure than ex situ Fe(III). This research provides an explanation for the superiority of in situ Fe(III) in phosphorus removal and highlights the importance of atomic-level structural differences between ex situ and in situ Fe(III) coprecipitates in water treatment.

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“…Three to six scans were performed for each sample. The detailed description of XAFS analysis was reported previously; , a summary is also provided in Section S1 of Supporting Information.…”

Section: Materials and Methodsmentioning

confidence: 99%

NOM-Induced Dissolution of Cr_xFe_1–x(OH)₃ Precipitates and Formation of Cr(III)-NOM-Fe Colloids under Oxic and Anoxic Conditions

Zhang

Liao

et al. 2022

ACS Earth Space Chem.

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Mixed Cr(III)–Fe(III) (hydr)oxides (Cr x Fe1–x (OH)3) are common reduction products of Cr(VI) that have long been considered as the sink of Cr in subsurface environments. While current field and laboratory studies have demonstrated that natural organic matter (NOMox) can dissolve Cr x Fe1–x (OH)3 under oxic conditions, much less is known regarding the dissolution of Cr x Fe1–x (OH)3 by reduced NOM (NOMred) and geochemical behaviors of released Cr(III) under anoxic conditions, which limited our ability to completely predict the cycle of Cr. This study provided new knowledge regarding the simultaneous dissolution of Cr x Fe1–x (OH)3 and formation of Cr(III)-NOM-Fe colloids by NOMox and NOMred under oxic and anoxic conditions. We showed that NOM dissolved Cr x Fe1–x (OH)3 via ligand-promoted dissolution under oxic conditions and reductive dissolution under anoxic conditions, releasing aqueous Cr(III) and Fe(III/II). Size fractionization results showed that the aqueous Cr(III) and Fe observed at high NOM concentration were Cr(III)-NOM-Fe colloids (ca. 3–450 nm). Dynamic light scattering results further revealed that the colloids had a particle size ranging from 79 to 167 nm and strongly negative surface charges (−40––17 mV). Cryogenic X-ray photoelectron spectroscopy and X-ray absorption fine structure measurements further indicated a close association of NOM with Cr and Fe within the particle structure. This study provides insights into the fate of Cr x Fe1–x (OH)3 in redox-dynamics and organic-rich environments, which is critical for evaluating the long-term stability of Cr remediation sites.

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Metal (Fe, Cu, and As) transformation and association within secondary minerals in neutralized acid mine drainage characterized using X-ray absorption spectroscopy

Cited by 34 publications

References 59 publications

Antimony Isotope Fractionation Revealed from EXAFS during Adsorption on Fe (Oxyhydr)oxides

Antimony Isotope Fractionation Revealed from EXAFS during Adsorption on Fe (Oxyhydr)oxides

Atomic-Level Structural Differences between Fe(III) Coprecipitates Generated by the Addition of Fe(III) Coagulants and by the Oxidation of Fe(II) Coagulants Determine Their Coagulation Behavior in Phosphate and DOM Removal

NOM-Induced Dissolution of Cr_xFe_1–x(OH)₃ Precipitates and Formation of Cr(III)-NOM-Fe Colloids under Oxic and Anoxic Conditions

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Metal (Fe, Cu, and As) transformation and association within secondary minerals in neutralized acid mine drainage characterized using X-ray absorption spectroscopy

Cited by 34 publications

References 59 publications

Antimony Isotope Fractionation Revealed from EXAFS during Adsorption on Fe (Oxyhydr)oxides

Antimony Isotope Fractionation Revealed from EXAFS during Adsorption on Fe (Oxyhydr)oxides

Atomic-Level Structural Differences between Fe(III) Coprecipitates Generated by the Addition of Fe(III) Coagulants and by the Oxidation of Fe(II) Coagulants Determine Their Coagulation Behavior in Phosphate and DOM Removal

NOM-Induced Dissolution of CrxFe1–x(OH)3 Precipitates and Formation of Cr(III)-NOM-Fe Colloids under Oxic and Anoxic Conditions

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NOM-Induced Dissolution of Cr_xFe_1–x(OH)₃ Precipitates and Formation of Cr(III)-NOM-Fe Colloids under Oxic and Anoxic Conditions