Metastability, nanocrystallinity and pseudo-solid solution effects on the understanding of schwertmannite solubility

Caraballo, Manuel A.; Rimstidt, J. Donald; Macías, Francisco; Nieto, José Miguel; Hochella, Michael F.

doi:10.1016/j.chemgeo.2013.09.023

Cited by 58 publications

(52 citation statements)

References 40 publications

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“…When the pH of the system is acidic enough (pH [2][3][4] [13]. Between pH 2.5 and 4, schwertmannite is, perhaps, the principal secondary mineral that forms from acid drainage [19,20].…”

Section: Introductionmentioning

confidence: 99%

Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

2014

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Sea level rise is able to change the geochemical conditions in coastal systems. In these environments, transport of contaminants can be controlled by the stability and adsorption capacity of iron oxides. The behavior of adsorbed and co-precipitated arsenic in jarosite, schwertmannite, ferrihydrite, and goethite in sea water (common secondary minerals in coastal tailings) was investigated. The aim of the investigation was to establish As retention and transport under a marine flood scenario, which may occur due to climate change. Natural and synthetic minerals with co-precipitated and adsorbed As were contacted with seawater for 25 days. During this period As, Fe, Cl, SO 4 , and pH levels were constantly measured. The larger retention capability of samples with co-precipitated As, in relation with adsorbed As samples, reflects the different kinetics between diffusion, dissolution, and surface exchange processes. Ferrihydrite and schwertmannite showed good results in retaining arsenic, although schwertmannite holding capacity was enhanced due its buffering capacity, which prevented reductive dissolution throughout the experiment. Arsenic desorption from goethite could be understood in terms of ion exchange between oxides and electrolytes, due to the charge difference generated by a low point-of-zero-charge and the change in stability of surface complexes between synthesis conditions and natural media. OPEN ACCESSMinerals 2014, 4 604

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“…When the pH of the system is acidic enough (pH [2][3][4] [13]. Between pH 2.5 and 4, schwertmannite is, perhaps, the principal secondary mineral that forms from acid drainage [19,20].…”

Section: Introductionmentioning

confidence: 99%

Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

2014

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“…The ideal chemical formula for schwertmannite is Fe 8 O 8 (OH) 8-2x (SO4) x , where x ranges between 1 and 1.75. Although the sulphate content range proposed by Bigham et al (1990) is widely accepted, a recent study by Caraballo et al (2013) pointed out that the proposed range was obtained with the data available in the 1990s. However, when more recent information on the chemical composition of natural schwertmannite particles is taken into account, a wider range (0.52 -1.84) is obtained.…”

Section: Characterization Of Iron Oxide Precipitatesmentioning

confidence: 99%

Surface Complexation Modelling of Arsenic and Copper Immobilization by Iron Oxide Precipitates Derived from Acid Mine Drainage

Otero-Fariña¹,

Gago²,

Antelo³

et al. 2015

BSGM

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Acid mine drainage (AMD) constitutes a serious environmental problem in mining areas due to the acidification of soils and aquatic systems, and the release of toxic metals. Many of the pollutants that occur in AMD display a high affinity for the surfaces of the aluminium and iron oxides that are typically present in systems affected by AMD. This binding affinity reduces the mobility of trace metals and metalloids, such as copper and arsenic, thus helping to mitigate contamination of aquatic systems. In the present study, water samples and iron-rich bed sediments were collected in areas affected by copper mining activities. A loose ochre-coloured precipitate occurring on the banks of a river close to an abandoned tungsten and tin mine was also sampled. The composition of the precipitate was established, and adsorption experiments were performed with copper and arsenate ions to determine the ability of natural iron precipitates to reduce the concentration of these ions in solution. Surface complexation models provided a good description of the behaviour of natural iron oxides in terms of copper and arsenate retention. Use of this type of model enables prediction of the distribution of pollutants between the solid and solution phases and analysis of their mobility in relation to environmental conditions (pH, ionic strength, presence of competing species, etc.).Keywords: Acid mine drainage, iron oxides, adsorption, trace elements, arsenic, surface complexation model. (pH, fuerza iónica, presencia de especies que compitan, etc.). Resumen El drenaje ácido de mina (AMD) constituye un importante problema ambiental debido a la acidificación y la liberación de metales tóxicos que produce en el suelo y en los sistemas acuáticos próximos a las zonas mineras. Existe una elevada afinidad de muchos de

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“…To gain insight into such processes, we plotted the effluent datasets from Main Seep, Bioreactor Inlet, Bioreactor Outlet, and System Outlet into the Eh-pH diagram for Fe-S-K-O-H system at 25 • C (Figure 7). Previous reports have listed highly variable thermodynamic data for schwertmannite and ferrihydrite [52][53][54] so the Eh-pH stability fields are largely symptomatic.…”

Section: Examination Of Eh-ph Diagrammentioning

confidence: 99%

“…Previous reports have listed highly variable thermodynamic data for schwertmannite and ferrihydrite [52][53][54] so the Eh-pH stability fields are largely symptomatic.…”

Section: Examination Of Eh-ph Diagrammentioning

confidence: 99%

Sulfur Isotope Fractionation as an Indicator of Biogeochemical Processes in an AMD Passive Bioremediation System

et al. 2017

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Sulfate, the main dissolved contaminant in acid mine drainage (AMD), is ubiquitous in watersheds affected by coal and metal mining operations worldwide. Engineered passive bioremediation systems (PBS) are low-cost technologies that remediate sulfate contamination by promoting (1) precipitation of sulfate-bearing compounds, such as schwertmannite and gypsum; and (2) microbially-mediated sulfate reduction (BSR) to sulfide with subsequent precipitation of sulfide minerals. In this study, chemical and sulfur isotopic data are used to infer multiple pathways for sulfate sequestration in the Tab-Simco PBS. By simultaneously monitoring sulfate concentrations and δ 34 S SO 4 values at four sampling points across the PBS, we (1) identified that the organic layer within the bioreactor was the primary site of BSR processes contributing to sulfate sequestration; (2) observed seasonal variations of BSR processes; (3) estimated that initially the BSR processes contributed up to 30% to sulfate sequestration in the Tab-Simco bioreactor; and (4) determined that BSR contribution to sulfate sequestration continuously declined over the PBS operational lifetime. Together, our results highlight the utility of combining geochemical and microbial fingerprinting techniques to decipher complementary processes involved in sulfur cycling in a PBS as well as the value of adding the sulfur isotope approach as an essential tool to help understand, predict, prevent and mitigate sulfate contamination in AMD-impacted systems.

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Metastability, nanocrystallinity and pseudo-solid solution effects on the understanding of schwertmannite solubility

Cited by 58 publications

References 40 publications

Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

Surface Complexation Modelling of Arsenic and Copper Immobilization by Iron Oxide Precipitates Derived from Acid Mine Drainage

Sulfur Isotope Fractionation as an Indicator of Biogeochemical Processes in an AMD Passive Bioremediation System

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