Oxidative dissolution of silver nanoparticles by synthetic manganese dioxide investigated by synchrotron X-ray absorption spectroscopy

Manning, Bruce A.; Kanel, Sushil R.; Guzman, Edgar; Brittle, Seth W.; Pavel, Ioana

doi:10.1007/s11051-019-4656-5

Cited by 6 publications

(14 citation statements)

References 61 publications

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“…Ultra-pure deionized (DI) water (>18.2 MΩ•cm) was used throughout this study. Synthetic potassium birnessite (δ-MnO 2 , hereafter MnO 2 ) was synthesized according to previous investigations [15]. Briefly, 1 L of heated (60 • C) 0.4 M KMnO 4 was reacted with 0.5 L heated (60 • C), concentrated HCl followed by storage in dialysis tubing immersed in DI water for 14 d until the K + concentration in the dialyzing solution decreased to <0.005 mM K. The MnO 2 solids were air-dried for 48 h under nitrogen and gently crushed and sieved to a <150 µm particle size.…”

Section: Materials and Synthesis Of δ-Mnomentioning

confidence: 99%

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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: Materials and Synthesis Of δ-Mnomentioning

confidence: 99%

“…All of these MnO 2 minerals are capable of oxidizing a wide variety of soil contaminants, including organic compounds such as phenol [12] and amine compounds [13,14]. Several inorganic contaminants including silver nanoparticles [15], Cr(III) [16] and As(III) [17] are also oxidized by MnO 2 .…”

Section: Introductionmentioning

confidence: 99%

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

2021

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“…aniline [40], aliphatic amine [41], and triazine [42] and inorganic ions such as Cr(III) [43,44] and As(III) [45]. Preliminary investigations in this study suggested that MnO2 also oxidizes AgNPs [37] and thus is an important environmental pathway whereby AgNPs are transformed to the more toxic Ag + ion.…”

mentioning

confidence: 78%

“…The AgNP samples were not stabilized with "capping" agents but left as bare, untreated AgNPs. The synthesized AgNPs were analyzed by high resolution transmission electron microscopy (HRTEM) using a Hitachi H-7600 TEM (100 kV) [37]. HRTEM samples were prepared by placing a droplet of AgNP suspension onto a carbon-coated copper grid (200-300 mesh, Ted Pella, Hatfield, PA) and dried under nitrogen.…”

Section: Silver Nanoparticle (Agnp) Synthesismentioning

confidence: 99%

“…Manganese dioxides exist in soil as several crystalline forms including the common MnO2 polymorphs of hollandite (α-MnO2), pyrolusite (β-MnO2), birnessite (δ-MnO2), and defect spinal (λ-MnO2) resulting from the diverse bonding orientations and patterns of the cross-linked, edge-shared, and corner-shared Mn(IV)O6 bipyramids (octahedra) [36]. Figure 1.1 gives an example of the birnessite crystal structure adapted from Manning et al [37] showing edge-sharing layers of Mn(IV)O6 octahedral units.…”

Section: Introductionmentioning

confidence: 99%

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Adsorption and Oxidative Dissolution of Silver Nanoparticles in Soil and Soil Mineral Suspensions

Guzman¹

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Synthetic silver nanoparticles (AgNPs) were studied due to their wide-spread use in industry and medical operations. This thesis investigated the reactions of AgNPs with soil and soil minerals, with a specific emphasis on synthetic birnessite (δ-MnO2) which is known to oxidize AgNPs to its toxic Ag + form. Reactions of AgNPs with iron oxide and soil samples showed that soil removes AgNPs from suspension and that the extent of removal (adsorption/oxidation) may be related to the Fe and Mn contents of a soil. Our investigations of AgNP reactions with δ-MnO2showed that this mineral is an important source of AgNP removal and oxidation. The Ag speciation methodology provided a reasonable estimation of the amount of both AgNP and Ag + in mixtures of the two species. We were unable to detect Ag + recovered from the reactions using the UV-VIS/MP-AES Ag speciation methodology due to strong adsorption of the Ag + ion oxidation product on MnO2 interlayer cation exchange sites, which was confirmed by Ag + /MnO2 experiments. The speciation method was found to be limited by small (~5%) differences between the Ag emission generated from pure AgNP vs. pure Ag + ion in sample solutions. This "nanoeffect" limited the quantitative speciation analysis to samples where the large (% level) proportions of the two Ag species are present. v

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Environmental behavior of silver nanomaterials in aquatic environments: An updated review

Yang,

Wang,

Liu

et al. 2024

Science of The Total Environment

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Oxidative dissolution of silver nanoparticles by synthetic manganese dioxide investigated by synchrotron X-ray absorption spectroscopy

Cited by 6 publications

References 61 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

Adsorption and Oxidative Dissolution of Silver Nanoparticles in Soil and Soil Mineral Suspensions

Environmental behavior of silver nanomaterials in aquatic environments: An updated review

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