INVESTIGATIONS INTO THE DEGASSING OF NYAMURAGIRA VOLCANO (D.R. CONGO, AFRICA) THROUGH SYNCHROTRON MICRO-XANES ANALYSIS

Manganese (Mn) is a major element in various aqueous and soil environments that is sometimes highly concentrated in mine water and other mineral processing wastewater. In this study, we investigated Mn removal from alkaline mine water (pH > 9) with an Mn-coated silica sand packed into a pilot-scale column reactor and examined the specific reaction mechanism using X-ray absorption near-edge structure (XANES) analysis and geochemical kinetic modeling. The kinetic effect of dissolved Mn(II) removal by birnessite (δ-Mn(IV)O2) at pH 6 and 8 was evaluated at different Mn(II)/Mn(IV) molar ratios of 0.1–10. Our results confirmed the positive effect of the presence of δ-MnO2 on the short-term removal (60 min) of dissolved Mn. XANES analysis results revealed that δ-MnO2 was more abundant than Mn(III)OOH in the reactor, which may have accumulated during a long-term reaction (4 months) after the reactor was turned on. A gradual decrease in dissolved Mn(II) concentration with depth was observed in the reactor, and comparison with the kinetic modeling result confirmed that δ-MnO2 interaction was the dominant Mn removal mechanism. Our results show that δ-MnO2 contents could play a significant role in controlling Mn removability from mine water in the reactor.

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Speciation of Ru Molecular Complexes in a Homogeneous Catalytic System: Fingerprint XANES Analysis Guided by Machine Learning

The Journal of Physical Chemistry C ◽

10.1021/acs.jpcc.1c09082 ◽

2021 ◽

Author(s):

E. G. Kozyr ◽

A. L. Bugaev ◽

S. A. Guda ◽

A. A. Guda ◽

K. A. Lomachenko ◽

...

Keyword(s):

Machine Learning ◽

Catalytic System ◽

Molecular Complexes ◽

Xanes Analysis

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XANES Analysis of L3,2Edges of Zinc Selenides with Transition Metals

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:19972193 ◽

1997 ◽

Vol 7 (C2) ◽

pp. C2-1201-C2-1202

Author(s):

M. Zimnal-Starnawska ◽

E. Czarnecka-Such ◽

A. Kisiel ◽

W. Frentrup ◽

W. Giriat

Keyword(s):

Transition Metals ◽

Xanes Analysis

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Hemeproteins: Recent Advances in Quantitative XANES Analysis

10.1063/1.2644508 ◽

2007 ◽

Cited By ~ 2

Author(s):

Alessandro Arcovito ◽

Maurizio Benfatto ◽

Paola D’Angelo ◽

Stefano Della Longa

Keyword(s):

Recent Advances ◽

Xanes Analysis

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Solving local structure around dopants in metal nanoparticles with ab initio modeling of X-ray absorption near edge structure

Physical Chemistry Chemical Physics ◽

10.1039/c6cp04030f ◽

2016 ◽

Vol 18 (29) ◽

pp. 19621-19630 ◽

Cited By ~ 21

Author(s):

Janis Timoshenko ◽

Atal Shivhare ◽

Robert W. J. Scott ◽

Deyu Lu ◽

Anatoly I. Frenkel

Keyword(s):

Ab Initio ◽

Metal Nanoparticles ◽

Local Structure ◽

Heterogeneous Catalysts ◽

Edge Structure ◽

X Ray ◽

Metal Impurities ◽

Local Environments ◽

X Ray Absorption ◽

Xanes Analysis

XANES analysis guided by ab initio modeling is proposed for refinement of local environments around metal impurities in heterogeneous catalysts.

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Preparation of Iron Catalysts Generated from Fe-Coagulated Sludge Produced by Ferric Chloride Coagulation of Wastewater

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1025-1026.645 ◽

2014 ◽

Vol 1025-1026 ◽

pp. 645-650

Author(s):

Supranee Foowut ◽

Tawanrat Palothaisit ◽

Natthadabhorn Boonlor ◽

Panida Prompinit ◽

Pinsuda Viravathana

Keyword(s):

Specific Surface ◽

Pore Volume ◽

Total Pore Volume ◽

Iron Catalysts ◽

Precipitation Method ◽

X Ray Diffraction ◽

X Ray ◽

Co Precipitation ◽

X Ray Absorption ◽

Xanes Analysis

In this work, the FexOy catalysts were prepared by the co-precipitation method. The catalysts were characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and Brunauer-Emmett-Teller (BET) surface analysis. From XRD results, the FexOy with the wastewater to coagulant ratio of 1:2 catalyst (FexOy-1:2) calcined at 600 °C for 6 h showed the presence of the wustite (FeO) form. XANES analysis showed the phase of FeO in FexOy-1:2 calcined at 600 °C for 6 h which corresponded to the result from XRD. The FexOy 1:1 catalyst had higher specific surface area and larger total pore volume compared to the FexOy 1:2 catalyst.

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