Arsenite oxidation and arsenic adsorption on birnessite in the absence and the presence of citrate or EDTA

Liang, Mengyu; Guo, Huaming; Xiu, Wei

doi:10.1007/s11356-020-10292-3

Cited by 13 publications

(4 citation statements)

References 94 publications

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“…Figure 1a shows a representative example of a large~8 µm MnO 2 particle with a complex surface roughness. A higher magnification image of this particle (Figure 1b) shows nanoscale plate-like structures similar to images of synthetic birnessite in previous studies [20,21]. Previous synthesis of potassium birnessite (KMnO 2 ) has shown similar morphologies that consist of mostly irregular, plate-shaped (100-200 nm) crystallites [22].…”

Section: Characterization Of Mnosupporting

confidence: 79%

Oxidation of Cr(III) to Cr(VI) and Production of Mn(II) by Synthetic Manganese(IV) Oxide

2021

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The heterogeneous oxidation of Cr(III) to Cr(VI), a toxic inorganic anion, by a synthetic birnessite (δ-MnO2) was investigated in batch reactions using a combination of analytical techniques including UV–Vis spectrophotometry, microwave plasma–atomic emission spectrometry, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR), to evaluate both the solution speciation of Cr(III)/Cr(VI) and the surface of the reacted δ-MnO2. The formation of dissolved Mn(II) was determined during the batch reactions to evaluate the extent and stoichiometry of the Cr(III) oxidation reaction. A stoichiometric 3:2 Mn(II):Cr(VI) molar relationship was observed in the reaction products. The reductive dissolution of the δ-MnO2 by Cr(III) resulted in a surface alteration from the conversion of Mn(IV) oxide to reduced Mn(II) and Mn(III) hydroxides. The results of this investigation show that naturally occurring Cr(III) will readily oxidize to Cr(VI) when it comes in contact with MnO2, forming a highly mobile and toxic groundwater contaminant.

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Section: Characterization Of Mnosupporting

confidence: 79%

Oxidation of Cr(III) to Cr(VI) and Production of Mn(II) by Synthetic Manganese(IV) Oxide

2021

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“…S1b). Contrasting with other organic ligands such as oxalate (Ying et al, 2020) or citrate (Liang et al, 2020), and consistent with preliminary data (not shown), the reaction between the pyrophosphate, which is considered to be a nonredox active ligand (Morgan et al, 2021), and birnessite could be disregarded.…”

Section: As(iii) Oxidation By Birnessite In the Presence Of Fe(ii) Wi...supporting

confidence: 63%

Solutions for an efficient arsenite oxidation and removal from groundwater containing ferrous iron

et al. 2023

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“…For example, exposure to Mn(III)-complexing PP has been shown to retard the activity of disordered Na-birnessite (δ-MnO 2 ) for Cr(III) to Cr(VI) conversion, whereas similar exposure enhances the oxidation of isovalent As(III) to As(V) by hexagonal birnessite . Contrary to this, adsorption of other Mn(III)-complexing ligands such as citrate or phosphate , suppresses the oxidation As(III) by hexagonal birnessite, which has been attributed to passivation of adsorption sites by ligand complexes. Thus, multiple coupled factors, in addition to the crystallographic structure and composition, likely influence the oxidative response of the birnessite.…”

Section: Introductionmentioning

confidence: 99%

Environmental Factors Controlling the Electronic Properties and Oxidative Activities of Birnessite Minerals

Wang

Chakrapani

2023

ACS Earth Space Chem.

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Recent studies of birnessite-type lattices show that they have an unusually low-lying band structure with an electron affinity value of 6.0 eV, which is the highest among all common oxides and sulfides in an aqueous solution. This study reports on the underlying mechanism through which environmental factors, such as organic and inorganic ligands, exert a strong influence on the band structure and oxidative reactivity of various synthetic and natural birnessite phases. Specifically, the study evaluated the effect of (i) disorder/crystallinity, (ii) common aqueous cations, and (iii) Mn(II) and Mn(III) complexing anionic ligands on Cr(III) to Cr(VI) oxidation activity, Mn dissolution, and the band structure of birnessite mineral with the aim of finding correlations between them. The results show that the high oxidative activity of various birnessites is coupled with their high electron affinity, which, in turn, is modulated by various aqueous anions and cations through their dynamic influence on the dissolution-controlled structural Mn(III)/Mn(II) content. Inorganic cations of different ionic radii and hydration strengths control the interlayer spacing of the basal sheets, while inorganic and organic aqueous anions control the extent of Mn(II) and Mn(III) complexation. Their combined effects are seen to govern the efficiency of Mn dissolution from the crystal, which modulates the birnessite activity and band structure.

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Arsenite oxidation and arsenic adsorption on birnessite in the absence and the presence of citrate or EDTA

Cited by 13 publications

References 94 publications

Oxidation of Cr(III) to Cr(VI) and Production of Mn(II) by Synthetic Manganese(IV) Oxide

Oxidation of Cr(III) to Cr(VI) and Production of Mn(II) by Synthetic Manganese(IV) Oxide

Solutions for an efficient arsenite oxidation and removal from groundwater containing ferrous iron

Environmental Factors Controlling the Electronic Properties and Oxidative Activities of Birnessite Minerals

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