Qualification of Thermodynamic Data for Geochemical Modeling of Mineral-Water Interactions in Dilute Systems

Wolery, Thomas J.; Jové-Colón, Carlos F.

doi:10.2172/850412

Cited by 34 publications

(6 citation statements)

References 2 publications

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“…For this study, both affinity and energy supply were evaluated using the above-described formulas. Analytical data was used to calculate the activities and solute speciation with the geochemical modeling code, EQ3 (Wolery & Jarek, 2003;Wolery & Jove-Colon, 2004). When modeling reactant and product activities, the concentration of major ions and trace elements reported in Leong et al (2021) were included.…”

Section: Energy Supply Calculationsmentioning

confidence: 99%

Energetically Informed Niche Models of Hydrogenotrophs Detected in Sediments of Serpentinized Fluids of the Samail Ophiolite of Oman

et al. 2022

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A geochemical gradient established by mixing between reduced, hyperalkaline (pH > 11), H2‐rich fluids generated through the process of serpentinization and surrounding surface water (pH ∼ 8) in the Samail Ophiolite of Oman provides an opportunity to characterize the geochemical and biological factors that influence the distribution of H2 oxidizing chemotrophs, hydrogenotrophs. In this study, 16S rRNA gene amplicon sequencing was implemented to characterize hydrogenotrophs in sediments underlying surface expressed serpentinized fluids in Oman. Hydrogenotroph phylotype distribution was evaluated as functions of chemical energy supplies for their given metabolic redox reactions. Through this approach, it was discovered that hydrogenotrophic taxa are likely constrained to sediments with overlying fluids that have <∼60 μm O2, including microorganisms of the genus, Hydrogenophaga. Sulfate reducers of the family, Thermodesulfovibrionaceae, likely require >∼10 μm SO4−2 for survival. In sediments with fluids having >∼10 μm SO4−2, sulfate reducers likely outcompete microorganisms of the methanogen genus, Methanobacterium, for H2. Additionally, differences in distribution between Thermodesulfovibrionaceae and Methanobacterium may be driven by the availability of electron acceptors and the redox reaction that is most energy yielding in the fluid. Taken together, observations from the Oman geochemical gradient result in a hydrogenotroph niche model that can be used to evaluate global distribution patterns of hydrogenotrophs in continental serpentinized fluids. On a global scale, based on previous studies, Methanobacterium is constrained to fluids that have <∼10 μm SO4−2.

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Section: Energy Supply Calculationsmentioning

confidence: 99%

Energetically Informed Niche Models of Hydrogenotrophs Detected in Sediments of Serpentinized Fluids of the Samail Ophiolite of Oman

et al. 2022

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“…This result is thought to originate from the difference in Gibbs free energy and the reaction path of TiF 4 and HF. Since the standard Gibbs free energy is −275.4 kJ mol −1 [54] and −1515.44 kJ mol −1 [55] for HF and TiF 4 , respectively, the TiF 4 decomposed more slowly, supplying F − ions at a lower rate than HF. Moreover, TiF 4 reacted with H 2 O, decomposing into Ti 4+ , OH − , and HF, and then supplied F − ions.…”

Section: Figures 3 and S6mentioning

confidence: 99%

Facet-controlled anatase TiO₂nanoparticles through various fluorine sources for superior photocatalytic activity

et al. 2016

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Reactive surface-exposed anatase TiO2 (a-TiO2) is highly desirable for applications requiring superior photocatalytic activity. In order to obtain a favorable surface, morphology control of the a-TiO2 using capping agents has been widely investigated. Herein, we systematically study the effects of different F sources (HF, TiF4, and NH4F) as the capping agent on the morphology control and photocatalytic activities of a-TiO2 in a hydrothermal process. When either HF or TiF4 was added, large truncated bipyramids formed with the photocatalytically active {001} facet, whereas the NH4F was not effective for facet control, yielding nanospheres similar to the pure a-TiO2. The morphology changes were related to the decomposition behaviors of the F sources in the solvent material: HF and TiF4 decomposed and supplied F(-) ions before a-TiO2 nucleation, which changed the nucleation rate and growth direction, leading to the resultant a-TiO2 morphology. On the other hand, NH4F supplied F(-) ions after a-TiO2 nucleation and could not change the growth behavior. In terms of the photocatalytic effect, the HF- and TiF4-treated a-TiO2 effectively decomposed ∼90% and ∼80% of methylene blue, respectively, in 1 h, while ∼60% was decomposed for the NH4F-treated a-TiO2. Note that pure a-TiO2 photocatalytically decomposed only ∼10% of methylene blue over the same time. These results pave the way to precise control of the facet of TiO2 through using different capping agents.

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“…EQ3/6 version 8.0a was used to both generate seawaterderived brines and simulate serpentinization reactions. EQ3/6 (Wolery & Jarek 2003;Wolery & Jove-Colon 2004;Wolery 2013) is a suite of codes that encompass both a speciation-solubility code (EQ3NR) as well as a reaction path modeling code (EQ6). The latter solves for the coexisting equilibrium in the fluid between gases, solid minerals, and aqueous species at a given temperature and pressure by using tabulated logK values supplied by the database and using modified Newton-Raphson methods to iterate until the solution converges (Nordstrom et al 1979;Wolery & Jarek 2003).…”

Section: Software Tools and Thermodynamic Databasesmentioning

confidence: 99%

Thermodynamic Predictions of Hydrogen Generation during the Serpentinization of Harzburgite with Seawater-derived Brines

Som,

Sevgen,

Suttle

et al. 2024

Planet. Sci. J.

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Salty aqueous solutions (brines) occur on Earth and may be prevalent elsewhere. Serpentinization represents a family of geochemical reactions where the hydration of olivine-rich rocks can release aqueous hydrogen, H2(aq), as a byproduct, and hydrogen is a known basal electron donor for terrestrial biology. While the effects of lithological differences on serpentinization products have been thoroughly investigated, effects focusing on compositional differences of the reacting fluid have received less attention. In this contribution, we investigate how the chemistry of seawater-derived brines affects the generation of biologically available hydrogen resulting from the serpentinization of harzburgite. We numerically investigate the serpentinization of ultramafic rocks at equilibrium with an array of brines at different water activities (a proxy for salt concentration in aqueous fluids and a determinant for habitability) derived from seawater evaporation. Because the existing supersaturation of aqueous calcium carbonate, a contributor to dissolved inorganic carbon (DIC) in natural seawater, cannot be captured in equilibrium calculations, we bookend our calculations by enabling and suppressing carbonate minerals when simulating serpentinization. We find that the extent of DIC supersaturation can provide an important control of hydrogen availability. Increased DIC becomes a major sink for hydrogen by producing formate and associated complexes when the reacting fluids are acidic enough to allow for CO2. Indeed, H2(aq) reduces CO2(aq) to formate, leading to a hydrogen deficit. These conclusions provide additional insights into the habitability of brine systems, given their potential for serpentinization across diverse planetary bodies such as on Mars and ocean worlds.

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Qualification of Thermodynamic Data for Geochemical Modeling of Mineral-Water Interactions in Dilute Systems

Cited by 34 publications

References 2 publications

Energetically Informed Niche Models of Hydrogenotrophs Detected in Sediments of Serpentinized Fluids of the Samail Ophiolite of Oman

Energetically Informed Niche Models of Hydrogenotrophs Detected in Sediments of Serpentinized Fluids of the Samail Ophiolite of Oman

Facet-controlled anatase TiO₂nanoparticles through various fluorine sources for superior photocatalytic activity

Thermodynamic Predictions of Hydrogen Generation during the Serpentinization of Harzburgite with Seawater-derived Brines

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Qualification of Thermodynamic Data for Geochemical Modeling of Mineral-Water Interactions in Dilute Systems

Cited by 34 publications

References 2 publications

Energetically Informed Niche Models of Hydrogenotrophs Detected in Sediments of Serpentinized Fluids of the Samail Ophiolite of Oman

Energetically Informed Niche Models of Hydrogenotrophs Detected in Sediments of Serpentinized Fluids of the Samail Ophiolite of Oman

Facet-controlled anatase TiO2nanoparticles through various fluorine sources for superior photocatalytic activity

Thermodynamic Predictions of Hydrogen Generation during the Serpentinization of Harzburgite with Seawater-derived Brines

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Product

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Facet-controlled anatase TiO₂nanoparticles through various fluorine sources for superior photocatalytic activity