Oxidation reactivity of As(III)-containing pyrites: Differences between structurally-incorporated and adsorbed As(III)

Liu, Yong-Ling; Wu, Shuai; Liang, Zongsheng; Liu, Yong; Ren, Haitao; Jia, Shao‐Yi; Han, Xu

doi:10.1016/j.chemgeo.2019.05.023

Cited by 13 publications

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“…In addition, the increasing nα and nβ values with increasing As(III) concentrations confirm that the presence of surface As(III) promotes the electron-transfer rate on Bi 2.15 WO 6 , thus enhancing its oxidation rate (Table S4). 58 3.7. Contribution of the LMCT Pathway to the Photooxidation of As(III).…”

Section: Resultsmentioning

confidence: 99%

Contribution of H-Abstraction to Photocatalytic Oxidation of As(III) by Bi_2.15WO₆

et al. 2021

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Mechanisms involved in the photocatalytic oxidation of As(III) are complicated in that various oxidizing species (such as h+, •OH, and O2 •–) have been suggested to play important roles in different photocatalytic systems. In this study, Bi2.15WO6 shows high reactivity in the photocatalytic oxidation of As(III) under visible light. Quenching experiments indicate that apart from h+, the surface superoxo (Bi–OO•) and peroxo species (Bi–OOH) formed on Bi2.15WO6 also contribute to As(III) oxidation. The increased production of H2O2 with increasingly consumed As(III) or with the addition of H-donors such as glucose and various phenolics further reveals that H-abstraction from As(III) or H-donors to Bi–OO• and then to Bi–OOH is an important pathway involved in H2O2 production and As(III) oxidation. In addition, various characterizations confirm that the As(III)–O–Bi(III) surface complexes formed on Bi2.15WO6 enhance the photocatalytic reactivity of Bi2.15WO6 via the ligand-to-metal charge transfer pathway. We therefore suggest that dissolved oxygen is sequentially reduced to Bi–OO• and then to Bi–OOH on Bi2.15WO6, accompanied by H-abstraction from adsorbed or aqueous As(III) to Bi–OO• and Bi–OOH with the formation of H2O2 and the oxidation of As(III). This work enriches our understanding of the mechanisms involved in the photocatalytic oxidation of As(III).

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Section: Resultsmentioning

confidence: 99%

Contribution of H-Abstraction to Photocatalytic Oxidation of As(III) by Bi_2.15WO₆

et al. 2021

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“…Although H 2 O 2 was also suggested as an important intermediate in the hematite-O 2 system under illumination, , no production of H 2 O 2 in the reaction systems indicates that H 2 O 2 has not been generated or the generated H 2 O 2 is immediately consumed by S(IV) or Fe (oxyhydr)oxides (Figure S7). , In this regard, the contribution of the produced H 2 O 2 to As(III) oxidation can also be excluded.…”

Section: Resultsmentioning

confidence: 99%

“…Considering the high adsorption capacities of Fh/Hem toward As(III) and As(V), , HCl solution was used to extract As(III) and As(V) adsorbed on Fh/Hem. − Namely, 1.0 mL of unfiltered sample was mixed with 1.0 mL of 1.0 M HCl for 30 min, and then, the mixture was filtered to analyze the corresponding concentrations of As(V) by the modified molybdate-blue method . HPLC (LC-16, Shimazu) was performed with a WondaSil C-18 column (250 mm × 4.6 mm, 5 μm).…”

Section: Methodsmentioning

confidence: 99%

“…Although H 2 O 2 was also suggested as an important intermediate in the hematite-O 2 system under illumination, 62,63 no production of H 2 O 2 in the reaction systems indicates that H 2 O 2 has not been generated or the generated H 2 O 2 is immediately consumed by S(IV) or Fe (oxyhydr)oxides (Figure S7). 41,64 In this regard, the contribution of the produced H 2 O 2 to As(III) oxidation can also be excluded. By contrast, the oxidation of As(III) was apparently inhibited by 3000 U mL −1 CAT (Figure 6), a highly efficient scavenger for dissolved or surface peroxo species, 21 indicating the formation of Fe(III)-OOH peroxo in those reaction systems.…”

Section: Contributions Of Differentmentioning

confidence: 99%

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Differences in the Oxidizing Species on the Surface of Metal-Doped Ferrihydrite and Hematite in the Alkaline S(IV)-O₂ Solution

Tian

Zhang

et al. 2023

ACS Earth Space Chem.

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Although inorganic Fe(IV)�O oxo and Fe(III)-OOH peroxo have attracted more attention in aqueous environments, direct evidence for the characterization and identification of those oxidizing species is still lacking. In this study, the doped Cu/Co increases the reactivity of ferrihydrite/hematite in oxidizing As(III) by S(IV)-O 2 under alkaline and dark conditions. Quenching experiments exclude the contributions of •OH, O 2 •− , SO 3 •− , SO 4 •− , SO 5 •−, HSO 5 − , and H 2 O 2 and confirm that peroxo and oxo are primary oxidizing species in As(III) oxidation. Electrochemical analyses indicate that Fe(IV)�O oxo and Fe(III)-OOH peroxo are primarily located on the surface of ferrihydrite and hematite. Selective oxidation of methyl phenyl sulfoxide and methyl phenyl sulfide to the corresponding oxidation products further reveals the presence of �Fe(IV)�O oxo on both ferrihydrite and hematite, and the doped Cu/ Co significantly decreases the produced �Fe(IV)�O oxo on ferrihydrite, while increases the produced �Fe(IV)�O oxo on hematite. Meanwhile, selective oxidation of benzyl alcohol to benzaldehyde indicates the presence of �Fe(III)-OOH peroxo on both ferrihydrite and hematite, and the doped Cu/Co apparently increases the produced �Fe(III)-OOH peroxo on ferrihydrite and hematite. Raman analysis further reveals the presence of �Fe(IV)�O oxo and �Fe(III)-OOH peroxo on pure and metal-doped ferrihydrite/hematite, which also confirms that the doped Cu/Co decreases the produced �Fe(IV)�O oxo on ferrihydrite and increases �Fe(IV)�O oxo on hematite, while apparently increasing �Fe(III)-OOH peroxo on both ferrihydrite and hematite. This study enriches our understanding on the oxidizing species in the S(IV)-mediated oxidation processes under alkaline conditions, providing new insight on the oxidation reactivity of surface peroxo and oxo species mediated by the doped metal ions.

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Catalytic cross‐coupling of aniline by pyrite and dissolved oxygen under alkaline conditions

Yi-ying

Song

Wang

et al. 2020

Applied Organom Chemis

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Pyrite catalyzes oxidation of various organic contaminants by dissolved oxygen (DO) under acidic conditions; however, the catalytic mechanism under alkaline conditions is still not clear. In this study, we observe increased oxidation rates of aniline with increasing pHs (7.0–11.0). Electron paramagnetic resonance (EPR) analysis and quenching experiments rule out contributions of •OH, O2•−, 1O2 and Fe (IV) to aniline oxidation and suggest that the Fe (III)–OOH peroxo and/or H2O2 are the primary oxidative species in the oxidation of aniline at pH 11.0. In addition, 200 mg L−1 H2O2 does not apparently increase the oxidation rate of aniline, which also rules out the predominant contribution of the produced H2O2 to aniline oxidation. We therefore suggest that the Fe (III)–OOH peroxo is indeed the primary oxidative species in the pyrite–DO system under alkaline conditions. Analyses of solid total organic carbon (TOC), gas chromatography–mass spectrometry and Fourier‐transform infrared spectroscopy further reveal that more than 83.3% aniline has been polymerized to polyaniline, instead of being mineralized into CO2 and H2O, indicating that H‐abstraction from aniline by the Fe (III)–OOH peroxo is an important step in the oxidation of aniline under alkaline conditions. This study provides new insight into the oxidative species in the pyrite–DO system, and opens a new door for organic degradations under alkaline conditions.

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Oxidation reactivity of As(III)-containing pyrites: Differences between structurally-incorporated and adsorbed As(III)

Cited by 13 publications

References 62 publications

Contribution of H-Abstraction to Photocatalytic Oxidation of As(III) by Bi_2.15WO₆

Contribution of H-Abstraction to Photocatalytic Oxidation of As(III) by Bi_2.15WO₆

Differences in the Oxidizing Species on the Surface of Metal-Doped Ferrihydrite and Hematite in the Alkaline S(IV)-O₂ Solution

Catalytic cross‐coupling of aniline by pyrite and dissolved oxygen under alkaline conditions

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Oxidation reactivity of As(III)-containing pyrites: Differences between structurally-incorporated and adsorbed As(III)

Cited by 13 publications

References 62 publications

Contribution of H-Abstraction to Photocatalytic Oxidation of As(III) by Bi2.15WO6

Contribution of H-Abstraction to Photocatalytic Oxidation of As(III) by Bi2.15WO6

Differences in the Oxidizing Species on the Surface of Metal-Doped Ferrihydrite and Hematite in the Alkaline S(IV)-O2 Solution

Catalytic cross‐coupling of aniline by pyrite and dissolved oxygen under alkaline conditions

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Contribution of H-Abstraction to Photocatalytic Oxidation of As(III) by Bi_2.15WO₆

Contribution of H-Abstraction to Photocatalytic Oxidation of As(III) by Bi_2.15WO₆

Differences in the Oxidizing Species on the Surface of Metal-Doped Ferrihydrite and Hematite in the Alkaline S(IV)-O₂ Solution