Modelling protocols for derivation of Fe(III) NICA constants and calculations of ambient Fe speciation and apparent Fe(III) solubility in seawater v1 (protocols.io.brc4m2yw)

Abstract. A new modelling study of the role of transition metal ions on cloud chemistry has been performed. Developments of the Model of Multiphase Cloud Chemistry (M2C2; Leriche et al., 2001) are described, including the transition metal ions reactivity emission/deposition processes and variable photolysis in the aqueous phase. The model is then applied to three summertime scenarios under urban, remote and marine conditions, described by Ervens et al. (2003). Chemical regimes in clouds are analyzed to understand the role of transition metal ions on cloud chemistry and especially, on HxOy chemistry, which consequently influences the sulphur and the VOCs chemistry in droplets. The ratio of Fe(II)/Fe(III) exhibits a diurnal variation with values in agreement with the available measurements of Fe speciation. In the urban case, sensitivity tests with and without TMI chemistry, show an enhancement of OH concentration in the aqueous phase when TMI chemistry is considered.

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Cu- and Fe-speciation in a composite zeolite catalyst for selective catalytic reduction of NOx: insights from operando XAS

Catalysis Science & Technology ◽

10.1039/d0cy01654c ◽

2021 ◽

Author(s):

Ilia A. Pankin ◽

Houeida Issa Hamoud ◽

Kirill A. Lomachenko ◽

Søren Birk Rasmussen ◽

Andrea Martini ◽

...

Keyword(s):

Selective Catalytic Reduction ◽

Absorption Spectroscopy ◽

Zeolite Catalyst ◽

Catalytic Reduction ◽

Mechanical Mixture ◽

X Ray ◽

Fe Speciation ◽

Reduction Of Nox ◽

Operando Xas ◽

X Ray Absorption

Cu-SAPO-34 (Cu-CZC) and Fe-mordenite (Fe-MOR) and their mechanical mixture (50 : 50) have been exhaustively investigated by means of operando X-ray absorption spectroscopy under NH3-SCR conditions.

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Links between seawater paleoredox and the formation of sediment-hosted massive sulphide (SHMS) deposits — Fe speciation and Mo isotope constraints from Late Devonian mudstones

Chemical Geology ◽

10.1016/j.chemgeo.2018.05.005 ◽

2018 ◽

Vol 490 ◽

pp. 45-60 ◽

Cited By ~ 5

Author(s):

Joseph M. Magnall ◽

Sarah A. Gleeson ◽

Simon W. Poulton ◽

Gwyneth W. Gordon ◽

Suzanne Paradis

Keyword(s):

Massive Sulphide ◽

Late Devonian ◽

Fe Speciation

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Spring flood induced shifts in Fe speciation and fate at increased salinity

Applied Geochemistry ◽

10.1016/j.apgeochem.2019.104385 ◽

2019 ◽

Vol 109 ◽

pp. 104385 ◽

Cited By ~ 2

Author(s):

S.D. Herzog ◽

S. Conrad ◽

J. Ingri ◽

P. Persson ◽

E.S. Kritzberg

Keyword(s):

Spring Flood ◽

Fe Speciation

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Assessing the utility of Fe/Al and Fe-speciation to record water column redox conditions in carbonate-rich sediments

Chemical Geology ◽

10.1016/j.chemgeo.2014.05.031 ◽

2014 ◽

Vol 382 ◽

pp. 111-122 ◽

Cited By ~ 92

Author(s):

M.O. Clarkson ◽

S.W. Poulton ◽

R. Guilbaud ◽

R.A. Wood

Keyword(s):

Water Column ◽

Redox Conditions ◽

Fe Speciation

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A model of Fe speciation and biogeochemistry at the Tropical Eastern North Atlantic Time-Series Observatory site

Biogeosciences ◽

10.5194/bg-6-2041-2009 ◽

2009 ◽

Vol 6 (10) ◽

pp. 2041-2061 ◽

Cited By ~ 32

Author(s):

Y. Ye ◽

C. Völker ◽

D. A. Wolf-Gladrow

Keyword(s):

Time Series ◽

Vertical Distribution ◽

North Atlantic ◽

Decay Time ◽

Particle Aggregation ◽

Dust Particles ◽

Dimensional Model ◽

One Dimensional ◽

Fe Speciation ◽

Eastern North Atlantic

Abstract. A one-dimensional model of Fe speciation and biogeochemistry, coupled with the General Ocean Turbulence Model (GOTM) and a NPZD-type ecosystem model, is applied for the Tropical Eastern North Atlantic Time-Series Observatory (TENATSO) site. Among diverse processes affecting Fe speciation, this study is focusing on investigating the role of dust particles in removing dissolved iron (DFe) by a more complex description of particle aggregation and sinking, and explaining the abundance of organic Fe-binding ligands by modelling their origin and fate. The vertical distribution of different particle classes in the model shows high sensitivity to changing aggregation rates. Using the aggregation rates from the sensitivity study in this work, modelled particle fluxes are close to observations, with dust particles dominating near the surface and aggregates deeper in the water column. POC export at 1000 m is a little higher than regional sediment trap measurements, suggesting further improvement of modelling particle aggregation, sinking or remineralisation. Modelled strong ligands have a high abundance near the surface and decline rapidly below the deep chlorophyll maximum, showing qualitative similarity to observations. Without production of strong ligands, phytoplankton concentration falls to 0 within the first 2 years in the model integration, caused by strong Fe-limitation. A nudging of total weak ligands towards a constant value is required for reproducing the observed nutrient-like profiles, assuming a decay time of 7 years for weak ligands. This indicates that weak ligands have a longer decay time and therefore cannot be modelled adequately in a one-dimensional model. The modelled DFe profile is strongly influenced by particle concentration and vertical distribution, because the most important removal of DFe in deeper waters is colloid formation and aggregation. Redissolution of particulate iron is required to reproduce an observed DFe profile at TENATSO site. Assuming colloidal iron is mainly composed of inorganic colloids, the modelled colloidal to soluble iron ratio is lower that observations, indicating the importance of organic colloids.

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Molecular-level understanding of malic acid retention mechanisms in ternary kaolinite-Fe(III)-malic acid systems: The importance of Fe speciation

Chemical Geology ◽

10.1016/j.chemgeo.2017.02.018 ◽

2017 ◽

Vol 464 ◽

pp. 69-75 ◽

Cited By ~ 8

Author(s):

Jianjun Yang ◽

Jin Liu ◽

Yongfeng Hu ◽

Cornelia Rumpel ◽

Nanthi Bolan ◽

...

Keyword(s):

Malic Acid ◽

Molecular Level ◽

Retention Mechanisms ◽

Fe Speciation

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Metal Mobility in a Mine-Affected Floodplain

Minerals ◽

10.3390/min10090814 ◽

2020 ◽

Vol 10 (9) ◽

pp. 814

Author(s):

Dariusz Ciszewski ◽

Urszula Aleksander-Kwaterczak

Keyword(s):

River Water ◽

Water Table ◽

Exchangeable Cations ◽

Metal Mobility ◽

Metal Mobilization ◽

Anaerobic Conditions ◽

Intrinsic Attenuation ◽

Fe Speciation ◽

Variable Potential

The study attempted to map and predict the remobilization of metals in a floodplain which had been heavily affected by long-term Zn–Pb mining. This research, based on Zn, Cd, Pb, Ca and Fe speciation, mineralogy and the stratigraphy of sediments which had accumulated over the distance of a dozen or so km from the mine, revealed variable potential for metal mobilization. The results suggest that a drop in the water table, something to be expected after the closure of a mine, would be accompanied by a decrease in the pH of the river water and can induce the remobilization of metals associated with carbonates and exchangeable cations over the short-reach downstream of the mine. However, the mobilization of contaminants may be impeded by the alkaline, impermeable stratum of loams, which play a pivotal role in maintaining anaerobic conditions and buffering the acidity resulting from the partial degradation of sulfides. Based on the findings of the study, it can be expected that the intrinsic attenuation will limit the need for remediation works, although monitoring river water quality is recommended to determine the need for any intervention in cases where permissible quality values have been exceeded over a longer period. Results of this research can be useful as a reference for remediation works planned in other contaminated river systems experiencing water table lowering, where the mobilization of contaminants as a consequence of sediment oxidization can be expected.

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Iron Speciation in Different Saharan Dust Advections and Effect of the Procedural Blank on the Results From X-ray Absorption Spectroscopy and Selective Leaching Experiments

Atmosphere ◽

10.3390/atmos11070735 ◽

2020 ◽

Vol 11 (7) ◽

pp. 735

Author(s):

Chiara Petroselli ◽

Beatrice Moroni ◽

Stefano Crocchianti ◽

Roberta Selvaggi ◽

Francesco Soggia ◽

...

Keyword(s):

Absorption Spectroscopy ◽

Saharan Dust ◽

Residual Fraction ◽

Selective Leaching ◽

Iron Speciation ◽

X Ray ◽

Fe Speciation ◽

Leaching Experiments ◽

X Ray Absorption

In this work, we applied X-ray Absorption Spectroscopy (XAS) and selective leaching experiments for investigating iron speciation in different dust advections collected on different unwashed quartz fiber filters. XAS analysis evidenced a predominance of Fe(III) in 6-fold coordination for Saharan dust and a trend towards Fe(II) and 4-fold coordination in the order: Saharan dust, mixed Saharan, and non-Saharan aerosol samples. The role of the sampling substrate was evaluated explicitly, including in the analysis a set of blank filters. We were able to pinpoint the possible contribution to the overall XAS spectrum of the residual Fe on quartz as the concentration decrease towards the blank value. In particular, the filter substrate showed a negligible effect on the structural trend mentioned above. Furthermore, selective leaching experiments evidenced a predominance of the residual fraction on Fe speciation and indicated the lowest Fe concentrations for which the blank contribution is <20% are 1 μ g for the first three steps of the procedure (releasing the acid-labile, reducible and oxidizable phases, respectively) and 10 μ g for the last step (dissolving the insoluble residuals).

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