In situ arsenic immobilisation for coastal aquifers using stimulated iron cycling: Lab-based viability assessment

Barron, Alyssa; Sun, Jing; Passaretti, Stefania; Sbarbati, Chiara; Barbieri, Maurizio; Colombani, Nicolò; Jamieson, James; Bostick, Benjamín C.; Zheng, Yan; Mastrocicco, Micòl; Petitta, Marco; Prommer, Henning

doi:10.1016/j.apgeochem.2021.105155

Cited by 10 publications

(16 citation statements)

References 92 publications

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“…The log-K d values of Hg range from 2.83 (GIT0, 4 June 2020) to 3.56 (GIT12, 5 June 2020, before the confluence the Pagliola creek), while those of As vary between 3.81 (GIT0, 4 June 2020) and 4.94 (GIT12 of 5 June 2020), suggesting that both elements are preferentially partitioned in the suspended phase (TSS). However, the As Log-K d values are significantly higher than those computed for Hg, indicating that arsenic has a higher affinity to TSS than to water, the former being likely characterized by Fe-hydroxides onto which As can be absorbed, e.g., [41][42][43][44]. This is further supported when the log-K d values of As and Hg between the stream sediments and TSS are considered, since the former tend to be <1, whereas those of Hg are up to 2.…”

Section: Partition Coefficients (Log-kd) and Yearly Estimate Mass Loa...mentioning

confidence: 85%

Mercury and Arsenic Discharge from Circumneutral Waters Associated with the Former Mining Area of Abbadia San Salvatore (Tuscany, Central Italy)

Lazzaroni

Zuccolini²,

Nisi

et al. 2022

IJERPH

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Dissolved and suspended toxic elements in water discharged from abandoned and active mining areas pose several critical issues, since they represent a threat to the environment. In this work, we investigated the water, suspended particulates, and stream sediments of a 2.1 km long creek (Fosso della Chiusa) that is fed by waters draining the galleries of the abandoned Hg mining area of Abbadia San Salvatore (Mt. Amiata, Tuscany, central Italy). The geochemical results show evidence that the studied matrices are characterized by relatively high concentrations of Hg and As, whereas those of Sb are generally close to or below the instrumental detection limit. Independent of the matrices, the concentration of As decreases from the emergence point to the confluence with the Pagliola creek. In contrast, Hg concentrations display more complex behavior, as water and sediment are mainly characterized by concentrations that significantly increase along the water course. According to the geoaccumulation index (Igeo), sediments belong to Class 6 (extremely contaminated) for Hg. The Igeo of As varies from Class 6, close to the emergence, to Class 2 (moderately contaminated), dropping to Class 0 (uncontaminated) at the confluence with the Pagliola creek. Finally, the total mass load of Hg and As entering the Pagliola creek was computed to be 1.3 and 0.5 kg/year, respectively, when a mean flow rate of 40 L/s was considered. The calculated loads are relatively low, but, when the Fosso della Chiusa drainage basin is taken into account, the specific load is comparable to, or even higher than, those of other mining areas.

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Section: Partition Coefficients (Log-kd) and Yearly Estimate Mass Loa...mentioning

confidence: 85%

Mercury and Arsenic Discharge from Circumneutral Waters Associated with the Former Mining Area of Abbadia San Salvatore (Tuscany, Central Italy)

Lazzaroni

Zuccolini²,

Nisi

et al. 2022

IJERPH

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“…In situ precipitation of Fe-bearing minerals (e.g., via chemical injections, , air-sparging, or biostimulation , ) has been proposed as a method to remediate As pollution for years. However, until very recently, , poorly ordered Fe(III) precipitates akin to 2LFh have traditionally been applied for in situ remediation. , The present study provides a compelling case that in situ magnetite production [e.g., via (electro)chemical , or biological methods] in the zone of As contamination can be an ideal strategy because 1) coprecipitation reliably achieves <1 μg/L aqueous As for both initial As oxidation states, which is difficult (if not impossible) with other Fe-bearing solids, , and 2) surface-bound As is effectively retained for extended periods regardless of the aging conditions (i.e., oxic vs anoxic environments). These benefits are particularly important for aquifers that experience rapid fluctuations in redox conditions, which is an expected impact of climate change in many regions affected by geogenic As .…”

Section: Discussionmentioning

confidence: 99%

The Enhanced Stability of Arsenic Coprecipitated with Magnetite during Aging: An XAS Investigation

Genuchten

2022

Ind. Eng. Chem. Res.

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The coprecipitation of magnetite (Fe3O4) with arsenic (As) is a potential remediation technique for As-contaminated groundwater that can be applied to meet increasingly stringent As drinking water limits. However, knowledge of the fate of As coprecipitated with magnetite during aging for extended periods is lacking, which is critical to predict the long-term efficiency of this As treatment strategy. In this work, I combined aqueous As measurements with solid-phase characterization by synchrotron-based Fe and As K-edge X-ray absorption spectroscopy (XAS) to track the transformation of magnetite and the speciation of coprecipitated As(V) or As(III) for up to a year in oxic or anoxic conditions. It was determined that the initial magnetite particle increased in crystallinity for all aging experiments, but some differences in solid-phase Fe speciation were detected depending on aging conditions. For the anoxic aging samples with initial As(V), a significant fraction (15% of the total Fe) of maghemite (a magnetic Fe oxide spinel with formula γ-Fe2O3) was identified, which was coupled to As(V) reduction [As(III) was ∼30% of the total sorbed As], suggesting electron transfer between magnetite and particle-bound As(V). In the oxic aging experiments, the initial particle crystallized, with a large fraction of Fe(III) (oxyhydr)oxides (i.e., maghemite and lepidocrocite, γ-FeOOH) in the final products. Despite increased crystallinity suggested by Fe XAS analysis, sorbed As was not released from the particles in any experiment (aqueous As never exceeded 1 μg/L). This remarkable stability of As coprecipitated with magnetite was revealed by As K-edge XAS to be largely due to the formation of distinct multinuclear As uptake modes [i.e., As(V) incorporation; hexanuclear 3C As(III) complexes]. These results demonstrate the unique potential of magnetite for long-term As sequestration.

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“…The dissolution of calcite was kinetically controlled using the rate expression r calcite = k 1 { normalH + } + k 2 { CO 2 } + k 3 { normalH 2 O } − k 4 { Ca 2 + } false{ HCO 3 false} − with the fourth term, calcite precipitation, as approximated by Appelo et al r calcite = ( k 1 false{ H + false} + k 2 false{ CO 2 false} + k 3 false{ H 2 normalO false} ) × ( 1 − ( IAP / K calcite ) 2 / 3 ) where constants k 1 , k 2 , and k 3 are temperature-dependent first-order rate constants, and curly brackets denote the activity of protons, aqueous CO 2 , and water. , The fourth term represents the temperature and P CO 2 -dependent precipitation of calcite as proposed by Appelo et al using the saturation state of calcite (ion activity product/solubility constant) to an exponent (2/3) representing the dissolution of spheres or cubes . The initial mass of the Fe minerals was estimated based on Fe concentrations determined by sequential extraction …”

Section: Methodsmentioning

confidence: 99%

“…63 The initial mass of the Fe minerals was estimated based on Fe concentrations determined by sequential extraction. 48…”

Section: Mineral Transformationsmentioning

confidence: 99%

Model-Based Analysis of Arsenic Retention by Stimulated Iron Mineral Transformation under Coastal Aquifer Conditions

Barron,

Jamieson,

Colombani

et al. 2024

ACS EST Water

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A multitude of geochemical processes control the aqueous concentration and transport properties of trace metal contaminants such as arsenic (As) in groundwater environments. Effective As remediation, especially under reducing conditions, has remained a significant challenge. Fe(II) nitrate treatments are a promising option for As immobilization but require optimization to be most effective.Here, we develop a process-based numerical modeling framework to provide an in-depth understanding of the geochemical mechanisms controlling the response of As-contaminated sediments to Fe(II) nitrate treatment. The analyzed data sets included time series from two batch experiments (control vs treatment) and effluent concentrations from a flow-through column experiment. The reaction network incorporates a mixture of homogeneous and heterogeneous reactions affecting Fe redox chemistry. Modeling revealed that the precipitation of the Fe treatment caused a rapid pH decline, which then triggered multiple heterogeneous buffering processes. The model quantifies key processes for effective remediation, including the transfer of aqueous As to adsorbed As and the transformation of Fe minerals, which act as sorption hosts, from amorphous to more stable phases. The developed model provides the basis for predictions of the remedial benefits of Fe(II) nitrate treatments under varying geochemical and hydrogeological conditions, particularly in high-As coastal environments.

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In situ arsenic immobilisation for coastal aquifers using stimulated iron cycling: Lab-based viability assessment

Cited by 10 publications

References 92 publications

Mercury and Arsenic Discharge from Circumneutral Waters Associated with the Former Mining Area of Abbadia San Salvatore (Tuscany, Central Italy)

Mercury and Arsenic Discharge from Circumneutral Waters Associated with the Former Mining Area of Abbadia San Salvatore (Tuscany, Central Italy)

The Enhanced Stability of Arsenic Coprecipitated with Magnetite during Aging: An XAS Investigation

Model-Based Analysis of Arsenic Retention by Stimulated Iron Mineral Transformation under Coastal Aquifer Conditions

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