Antimony Fixation in Solid Phases at the Hydrothermal Field of Kolumbo Submarine Arc-Volcano (Santorini): Deposition Model and Environmental Implications

Kilias, Stephanos P.; Gousgouni, M.; Godelitsas, Athanasios; Gamaletsos, P.; Mertzimekis, T. J.; Nomikou, P.; Argyraki, Ariadne; Goettlicher, J.; Steininger, Ralph; Papanikolaou, Dimitros

doi:10.12681/bgsg.14276

Cited by 8 publications

(8 citation statements)

References 15 publications

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“…The positions of both pre-peak (4135.5 eV) and L 3 -edge (4145 eV) are independent of Sb content and are attributed solely to Sb 5+ species, which according to Kilias et al in the spectra of Fe 3+ Sb 5+ O 4 are located at ~4135 eV and ~4144 eV, respectively. 25 This confirms our previous conclusions, based on electrical and thermal studies, that antimony in the lanthanum orthoniobate structure maintains an oxidation state of 5+. 5,6 In this study, we confirm that a higher oxidation state of antimony in lanthanum orthoniobate is maintained in the bulk material, not just at the surface.…”

Section: X-ray Absorption Spectroscopy (Xas)supporting

confidence: 91%

“…One can note that in the spectra of LaNb 1‐ x Sb x O 4‐δ neither the pre‐peak nor white line (WL) characteristic of the Sb 3+ species are visible (Figure 3). The positions of both pre‐peak (4135.5 eV) and L 3 ‐edge (4145 eV) are independent of Sb content and are attributed solely to Sb 5+ species, which according to Kilias et al in the spectra of Fe 3+ Sb 5+ O 4 are located at ~4135 eV and ~4144 eV, respectively 25 . This confirms our previous conclusions, based on electrical and thermal studies, that antimony in the lanthanum orthoniobate structure maintains an oxidation state of 5+ 5,6 .…”

Section: Resultsmentioning

confidence: 82%

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Antimony substituted lanthanum orthoniobate proton conductor – Structure and electronic properties

et al. 2020

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X‐ray and neutron diffraction have been utilized to analyze the crystalline and electronic structure of lanthanum orthoniobate substituted by antimony. Using X‐ray absorption spectroscopy and photoelectron spectroscopy, changes in the electronic structure of the material upon substitution have been analyzed. The structural transition temperature between fergusonite and scheelite phases for 30 mol% antimony substitution was found to be 15°C. Based on the neutron data, the oxygen nonstoichiometry was found to be relatively low. Moreover no influence on the position of the valence band maximum was observed. The influence of the protonation on the electronic structure of constituent oxides has been studied. Absorption data show that the incorporation of protonic defects into the lanthanum orthoniobate structure leads to changes in lanthanum electronic structure and a decrease in the density of unoccupied electronic states.

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Section: X-ray Absorption Spectroscopy (Xas)supporting

confidence: 91%

Section: Resultsmentioning

confidence: 82%

Antimony substituted lanthanum orthoniobate proton conductor – Structure and electronic properties

et al. 2020

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“…In addition to a magmatic volatile signature, acid-sulphate (advanced argillic) alteration, sulphosalts (e.g., enargite, Cu 3 AsS 4 ) typical for high-sulphidation conditions (Einaudi et al 2003) and high contents of economically important metals (e.g., Cu and Au) in some submarine arc and back-arc hydrothermal systems imply that they may be comparable to epithermal-porphyry deposits on land, such as the worldclass Far Southeast-Lepanto Cu-Au deposits (Philippines; Hedenquist et al 1998). This includes, for example, the magmatic-hydrothermal systems of Brothers volcano (Kermadec arc; de Ronde et al 2005;Berkenbosch et al 2012) and Kolumbo volcano (Hellenic arc; Kilias et al 2013Kilias et al , 2016, as well as SuSu Knolls in the Manus back-arc basin Yeats et al 2014;Thal et al 2016). Hence, arc-hosted hydrothermal systems are characteristically distinct in terms of their chemical and mineralogical composition compared to those along midocean ridges, which were interpreted to be the classic modern analogues of volcanic-hosted massive sulphide (VHMS) deposits mined on land (Hannington et al 1998de Ronde et al 2014;Keith et al 2016b).…”

Section: Electronic Supplementary Materialsmentioning

confidence: 99%

Constraints on the source of Cu in a submarine magmatic-hydrothermal system, Brothers volcano, Kermadec island arc

Keith

Haase

Klemd

et al. 2018

Contrib Mineral Petrol

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Most magmatic-hydrothermal Cu deposits are genetically linked to arc magmas. However, most continental or oceanic arc magmas are barren, and hence new methods have to be developed to distinguish between barren and mineralised arc systems. Source composition, melting conditions, the timing of S saturation and an initial chalcophile element-enrichment represent important parameters that control the potential of a subduction setting to host an economically valuable deposit. Brothers volcano in the Kermadec island arc is one of the best-studied examples of arc-related submarine magmatic-hydrothermal activity. This study, for the first time, compares the chemical and mineralogical composition of the Brothers seafloor massive sulphides and the associated dacitic to rhyolitic lavas that host the hydrothermal system. Incompatible trace element ratios, such as La/Sm and Ce/Pb, indicate that the basaltic melts from L'Esperance volcano may represent a parental analogue to the more evolved Brothers lavas. Copper-rich magmatic sulphides (Cu > 2 wt%) identified in fresh volcanic glass and phenocryst phases, such as clinopyroxene, plagioclase and Fe-Ti oxide suggest that the surrounding lavas that host the Brothers hydrothermal system represent a potential Cu source for the sulphide ores at the seafloor. Thermodynamic calculations reveal that the Brothers melts reached volatile saturation during their evolution. Melt inclusion data and the occurrence of sulphides along vesicle margins indicate that an exsolving volatile phase extracted Cu from the silicate melt and probably contributed it to the overlying hydrothermal system. Hence, the formation of the Cu-rich seafloor massive sulphides (up to 35.6 wt%) is probably due to the contribution of Cu from a bimodal source including wall rock leaching and magmatic degassing, in a mineralisation style that is hybrid between Cyprus-type volcanic-hosted massive sulphide and subaerial epithermal-porphyry deposits.

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“…This indicates a highly crystalline local environment, in contrast with the broader features and higher local disorder found in the Sb2O4. 39,41 We can thus conclude that the state of the Sb is very similar in the Mn, Co, and Ni antimonates, but shows more mixed character in the Fe antimonate.…”

Section: Table 1 Summary Of Characterization For Antimonates and Oxidesmentioning

confidence: 72%

First-row Transition Metal Antimonates for the Oxygen Reduction Reaction

Gunasooriya

Kreider

Liu

et al. 2021

Preprint

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The development of inexpensive and abundant catalysts with high activity, selectivity, and stability for the oxygen reduction reaction (ORR) is imperative for the widespread implementation of fuel cell devices. Herein, we present a combined theoretical-experimental approach to discover and design first-row transition metal antimonates as promising electrocatalytic materials for the ORR. Theoretically, we identify first-row transition metal antimonates – MSb2O6, where M = Mn, Fe, Co, and Ni – as non-precious metal catalysts with promising oxygen binding energetics, conductivity, thermodynamic phase stability and aqueous stability. Among the considered antimonates, MnSb2O6 shows the highest theoretical ORR activity based on the 4e− ORR kinetic volcano. Experimentally, nanoparticulate transition metal antimonate catalysts are found to have a minimum of a 2.5-fold enhancement in intrinsic mass activity (on transition metal mass basis) relative to the corresponding transition metal oxide at 0.7 V vs RHE in 0.1 M KOH. MnSb2O6 is the most active catalyst under these conditions, with a 3.5-fold enhancement on a per Mn mass activity basis and 25-fold enhancement on a surface area basis over its antimony-free counterpart. Electrocatalytic and material stability are demonstrated over a 5 h chronopotentiometry experiment in the stability window identified by Pourbaix analysis. This study further highlights the stable and electrically conductive antimonate structure as a promising framework to tune the activity and selectivity of non-precious metal oxide active sites for ORR catalysis.

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Antimony Fixation in Solid Phases at the Hydrothermal Field of Kolumbo Submarine Arc-Volcano (Santorini): Deposition Model and Environmental Implications

Abstract: Antimony, an emergent global contaminant, that is hydrothermally discharged along with other epithermal metals (-loids) (Au, As, Hg, Ag, Tl, Ag)

Cited by 8 publications

References 15 publications

Antimony substituted lanthanum orthoniobate proton conductor – Structure and electronic properties

Antimony substituted lanthanum orthoniobate proton conductor – Structure and electronic properties

Constraints on the source of Cu in a submarine magmatic-hydrothermal system, Brothers volcano, Kermadec island arc

First-row Transition Metal Antimonates for the Oxygen Reduction Reaction

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