Approaching the geochemical complexity of As(V)-contaminated systems through thermodynamic modeling

Vaca-Escobar, Katherine; Villalobos, Mario; Pi‐Puig, Teresa; Zanella, Rodolfo

doi:10.1016/j.chemgeo.2015.06.007

Cited by 2 publications

(2 citation statements)

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“…A considerable decrease in the adsorption of As(V) to a large goethite was found when the three components were added at a ratio of 1/1/1, in a similar fashion to the decrease observed in the presence of Cl -and in the absence of Cu(II), due to formation of the extremely insoluble mimetite mineral (Vaca-Escobar et al, 2015). The adsorption decrease in the presence of Cu(II) was caused by the precipitation of a mixed-metal arsenate called duftite: PbCu(AsO 4 )(OH).…”

Section: Discussionmentioning

confidence: 61%

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Modeling the additive effects of Pb(II) and Cu(II) on the competitive attenuation of As(V) through solid precipitation versus adsorption to goethite

Vaca-Escobar¹,

Villalobos²

2015

BSGM

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Mine-related activities cause widespread contamination of aqueous environments with high concentrations of arsenic and accompanying heavy metals. The natural attenuation of As(V) in soils and groundwater under oxic conditions occurs mainly through sorption processes to iron and aluminum (hydr)oxides; as well as through the formation of highly insoluble heavy metal(II) arsenates.In the present investigation we used thermodynamic modeling to predict the environmental geochemical behavior of As(V) in the presence of Pb(II), Cu(II) and goethite, in an effort to approach the complexity of multi-component real contaminated scenarios. The key to this modeling was the coupling of a highly robust Surface Complexation Model of As(V) adsorption to goethite, which uses combined tenets of the Triple-Layer and CD-MUSIC models, together with appropriate metal(II) arsenate solid formation constants as well as those of all chemical equilibria taking place in the aqueous phase. Mixed-metal arsenates were predicted to form and increase the predominance region of the precipitation reactions for a highly surface-reactive goethite, at the expense of the adsorption mechanism, but the model yielded no aqueous As(V) released at any condition investigated.Keywords: Adsorption, precipitation, arsenate, goethite, lead, copper, Surface Complexation Model, Triple-Layer Model, CD-MUSIC Model. Resumen Las actividades relacionadas con la minería provocan contaminación extendida de ambientes acuosos conjuntamente de arsénico y metales pesados. La atenuación natural de As(V) en suelos y acuíferos en condiciones óxicas ocurre principalmente a través de procesos de adsorción a (hidr)óxidos de hierro y aluminio; así como a través de la formación de arseniatos de metales(II) pesados altamente insolubles. En esta investigación utilizamos modelación termodinámica para predecir el comportamiento geoquímico ambiental del As(V) en presencia de Pb(II), Cu(II) y goetita, tratando de aproximarnos a la complejidad de escenarios multicomponentes de contaminación

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Section: Discussionmentioning

confidence: 61%

“…For larger more surface-reactive goethites, the adsorption mechanism prevails, and precipitation does not occur until all surface sites are occupied, except in the presence of chloride because of mimetite formation, which is considerably more insoluble than other lead arsenates (Vaca-Escobar et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

Modeling the additive effects of Pb(II) and Cu(II) on the competitive attenuation of As(V) through solid precipitation versus adsorption to goethite

Vaca-Escobar¹,

Villalobos²

2015

BSGM

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CO2 seawater acidification by CCS-simulated leakage: Kinetic modelling of Zn, Pb, Cd, Ni, Cr, Cu and As release from contaminated estuarine sediment using pH-static leaching tests

Martín-Torre

Ruiz

Galán

et al. 2016

International Journal of Greenhouse Gas Control

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CO 2 seawater acidification by CCS-simulated leakage: Kinetic modelling of Zn, Pb, Cd, Ni, Cr, Cu and As release from contaminated estuarine sediment using pH-static leaching tests a b s t r a c t A modified pH-dependent leaching test with continuous pH control that employed CO 2 to acidify a seawater-sediment mixture is used to address Zn, Pb, Cd, Ni, Cr, Cu and As release from contaminated estuarine sediments under the influence of acidification processes. Long-term (480 h) leaching experiments at pH values of 7.0, 6.5 and 6.0 are performed. The different evolutionary patterns of the redox potential and Fe release at pH = 6 with respect to the other pH values shows the need to assess the influence of the initial Fe content in seawater upon elemental release. Hence, assays at pH = 6.0 are conducted using natural seawater with Fe concentrations between 9.02 and 153 g/L. A set of in-series reactions for trace elements, Fe and other ions associated with Fe is proposed to model a Fe/multi-ion-dependent mechanism for trace metal release. The maximum concentration of each contaminant that can be released from the sediment and the kinetic parameters of the proposed model are completed for the studied pH values, for good consistency between the experimental and simulated mobilisation of each studied element.

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Approaching the geochemical complexity of As(V)-contaminated systems through thermodynamic modeling

Cited by 2 publications

References 36 publications

Modeling the additive effects of Pb(II) and Cu(II) on the competitive attenuation of As(V) through solid precipitation versus adsorption to goethite

Modeling the additive effects of Pb(II) and Cu(II) on the competitive attenuation of As(V) through solid precipitation versus adsorption to goethite

CO2 seawater acidification by CCS-simulated leakage: Kinetic modelling of Zn, Pb, Cd, Ni, Cr, Cu and As release from contaminated estuarine sediment using pH-static leaching tests

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