Ni speciation in a New Caledonian lateritic regolith: A quantitative X-ray absorption spectroscopy investigation

Dublet, Gabrielle; Juillot, Farid; Morin, Guillaume; Fritsch, Emmanuel; Fandeur, D.; Ona-Nguéma, Georges; Brown, Gordon E.

doi:10.1016/j.gca.2012.07.030

Cited by 101 publications

(100 citation statements)

References 62 publications

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“…It is also lower than the one of 0.56 calculated from the data of Brindley et al . In cases of mixed layering between talc‐like and serpentine, the Si/(Mg + Ni + Si) ratio varied between 0.5 and 0.4 …”

Section: Resultssupporting

confidence: 86%

Raman spectra of Ni–Mg kerolite: effect of Ni–Mg substitution on O–H stretching vibrations

Cathelineau

Caumon

Massei

et al. 2015

J Raman Spectroscopy

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The Ni‐rich mineral phases constituting the Ni‐ores in New Caledonia are dominated in most cases by kerolite–pimelite series, also called talc‐like minerals. Despite their economic and geologic interests, the crystallographic structures of these minerals are not fully understood. In order to improve the knowledge of their crystallographic structure, a set of natural talc‐like minerals of varying Ni/Mg ratio was selected. A combination of SEM, EMPA, TEM, and Raman analysis shows that the studied mineral contains only one mineral phase identified as the kerolite–pimelite series. Although kerolite and pimelite are not currently recognized as distinct minerals by the IMA, this study shows that these minerals exist as distinct minerals without any mixed layering with other mineral phases such as serpentine or other sheet silicates. The solid solution between the Ni and Mg endmembers was complete without any gap, corresponding to a Ni–Mg substitution in the octahedral sheet. The Raman spectra in the OH stretching vibration region of representative samples covering the whole range of Ni–Mg substitution show a continuous and significant evolution from the Mg to the Ni endmember. The signal was decomposed into nine Gaussian–Lorentzian functions, but the large overlapping of the peaks and the complexity of the band structure prevent any interpretation of the spectra from a structural point of view. Finally, the problem is formalized as a multivariate curve resolution (MCR) which is solved using the Bayesian Positive Source Separation (BPSS) algorithm. This reveals that four possible arrangements of Ni and Mg in the octahedral sheet are encountered, and these arrangements are dependent on the Ni–Mg substitution rate. It also confirms that Raman microspectroscopy can be very efficient in quick evaluation of the Ni content of the mineral. Copyright © 2015 John Wiley & Sons, Ltd.

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Section: Resultssupporting

confidence: 86%

Raman spectra of Ni–Mg kerolite: effect of Ni–Mg substitution on O–H stretching vibrations

Cathelineau

Caumon

Massei

et al. 2015

J Raman Spectroscopy

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“…Multiple scans were 196 averaged to improve the signal to noise ratio. The Athena program was used for averaging 197 replicate scans and energy calibration (Ni foil with inflection point set to 8334.5 eV), and the 198 Artemis program was used to generate phase and amplitude paths for Ni The Ni K-edge EXAFS model was based on published coordination number (CN) 224 ratios of a short and long Ni-Fe and Zn-Fe paths in the second shell of Ni K-edge EXAFS 225 data from Ni/Zn-adsorbed 2-line ferrihydrite samples (Table 3) (Manceau and Gates, 1997;226 Carvalho-E- Silva et al, 2003;Arai, 2008;Dublet et al, 2012;Cismasu et al, 2013). Reported 227 CN ratios for Ni-sorbed 2-line ferrihydrite ranged from 0.4 :0.7 (CNshort :CNlong) with a 228 maximum total second-shell CN of 5 (Arai, 2008).…”

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confidence: 99%

“…The magnitude of the Ni isotope fractionation factor ∆ 60/58 Nimin-aq (equation 2) between the have shown that adsorption reactions are often accompanied by significant isotope 430 fractionation processes that may vary according to sorbent composition and sorbate structure. (Waychunas et al, 2002;Arai, 2008;Juillot et al, 2008;Dublet et al, 2012; 477 Cismasu et al, 2013). It was demonstrated that Ni sorbed on ferrihydrite occurs in octahedral 478 coordination between Ni-O6 and Fe-O6 polyhedra with interatomic distances in the range of 479 3.05-3.08 Å for edge-sharing type 1 surface complexes, 3.19-3.12 Å for edge-sharing type 2, 480 and 4.03-4.07 Å for corner-sharing (Arai, 2008).…”

mentioning

confidence: 99%

Variable Ni isotope fractionation between Fe-oxyhydroxides and implications for the use of Ni isotopes as geochemical tracers

et al. 2018

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Nickel (Ni) isotopes have recently emerged as a new biogeochemical tracer in marine environments, but our understanding of the mechanisms of Ni isotope fractionation in natural systems with regards to its fractionation by mineral surfaces is incomplete. This study aims to provide experimental constraints on Ni isotope fractionation during adsorption to goethite and 2-line ferrihydrite, two Fe minerals that vary in terms of distinct crystalline properties. We conducted two types of adsorption experiments: one with variable pH (5.0 to 8.0) and constant initial Ni concentration, one at a constant pH of 7.7 and variable initial Ni concentrations. Isotopic measurements were made on both the solid phase and the supernatant solutions in order to determine the Ni isotope fractionation factors (Δ60/58Nimin-aq = δ60/58Nimin − δ60/58Niaq) between the mineral and aqueous phases. Our results show preferential adsorption of lighter Ni isotopes during adsorption of Ni to Fe oxyhydroxides presumably under conditions of near equilibrium conditions. Adsorption to goethite generates the greatest fractionation, with Δ60/58Nimin-aq = −0.77 ± 0.23‰ (n = 14, 2sd), whereas adsorption to 2-line ferrihydrite samples yield Δ60/58Nimin-aq = −0.35 ± 0.08‰ (n = 16, 2sd). Using Ni K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy, we found that Ni forms an inner-sphere complex and that its coordination environment does not vary significantly with pH nor with surface loading. In addition, we found no evidence of Ni incorporation into the mineral. We suggest that the more than two-fold increase in Ni isotope fractionation in goethite relative to 2-line ferrihydrite is due to the lower Ni-Fe coordination number in the second shell, which results in the formation of a weaker surface complex and thus favors the adsorption of lighter Ni isotopes. These results show that Ni isotope fractionation during sorption by Fe-oxyhydroxides is dependent on mineralogy, which has important implications for the use of Ni isotopes as environmental tracers and the interpretation of their record in sedimentary rocks. 93 metal/metalloid isotope systems such as Cu, Ge, Mo and Zn (Pokrovsky et al., 2008; Li and 94 Liu, 2010; Wasylenki et al., 2011; Pokrovsky et al., 2014). These experimental data are 95 crucial to interpret the trace metal isotopic records in Iron Formations, where the mechanism 96 of formation of Fe-oxyhydroxides-precursor mineral phases and scavenging of trace metals 97 are poorly known, and to evaluate the preservation of the isotopic signal during 98 recrystallization. The role of iron oxides recrystallization on the Ni cycling is also important 99 6 to consider as it could have impacted the Ni signal preserved in Iron Formations (Frierdich et 100 al., 2011). 101 To address this problem, we conducted Ni adsorption experiments on two synthetic 102 Fe-oxyhydroxides, 2-line ferrihydrite and goethite, as a function of pH, variable Ni loading to 103 pre-formed minerals, (i.e., no co-precipitation) and duration of experiments. Our goal...

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“…In New Caledonia, mangroves act as a barrier between the largest lagoon in the world and lateritic soils exploited for their richness in trace metals, mainly Ni and Cr. Lateritic soils are primarily composed of Fe(III)-bearing goethite and phyllosilicates [42]. The mangrove studied here does not develop downstream an ultramafic watershed.…”

Section: Distribution and Speciation Of Redox Sensitive Elements: Iromentioning

confidence: 88%

Concentrations and Fractionation of Carbon, Iron, Sulfur, Nitrogen and Phosphorus in Mangrove Sediments Along an Intertidal Gradient (Semi-Arid Climate, New Caledonia)

Deborde

Marchand

Molnar

et al. 2015

JMSE

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Abstract:In mangrove ecosystems, strong reciprocal interactions exist between plant and substrate. Under semi-arid climate, Rhizophora spp. are usually predominant, colonizing the seashore, and Avicennia marina develops at the edge of salt-flats, which is the highest zone in the intertidal range. Along this zonation, distribution and speciation of C, Fe, S, N, and P in sediments and pore-waters were investigated. From the land-side to the sea-side of the mangrove, sediments were characterized by I/ increase in: (i) water content; (ii) TOC; (iii) mangrove-derived OM; II/ and decrease in: (i) salinity; (ii) redox; (iii) pH; (iv) solid Fe and solid P. Beneath Avicennia and Rhizophora, TS accumulated at depth, probably as a result of reduction of iron oxides and sulfate. The loss of total Fe observed towards the sea-side may be related to sulfur oxidation and to more intense tidal flushing of dissolved components. Except the organic forms, dissolved N and P concentrations were very low OPEN ACCESSJ. Mar. Sci. Eng. 2015, 3 53beneath Avicennia and Rhizophora stands, probably as a result of their uptake by the root systems. However, in the unvegetated salt-flat, NH4 + can accumulate in organic rich and anoxic layers. This study shows: (i) the evolution of mangrove sediment biogeochemistry along the intertidal zone as a result of the different duration of tidal inundation and organic enrichment; and (ii) the strong links between the distribution and speciation of the different elements.

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Ni speciation in a New Caledonian lateritic regolith: A quantitative X-ray absorption spectroscopy investigation

Cited by 101 publications

References 62 publications

Raman spectra of Ni–Mg kerolite: effect of Ni–Mg substitution on O–H stretching vibrations

Raman spectra of Ni–Mg kerolite: effect of Ni–Mg substitution on O–H stretching vibrations

Variable Ni isotope fractionation between Fe-oxyhydroxides and implications for the use of Ni isotopes as geochemical tracers

Concentrations and Fractionation of Carbon, Iron, Sulfur, Nitrogen and Phosphorus in Mangrove Sediments Along an Intertidal Gradient (Semi-Arid Climate, New Caledonia)

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