A revised Pitzer model for low-temperature soluble salt assemblages at the Phoenix site, Mars

Toner, J. D.; Catling, David C.; Light, Bonnie

doi:10.1016/j.gca.2015.06.011

Cited by 37 publications

(61 citation statements)

References 65 publications

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“…4 Time series of RH and normalized sample mass in an experiment designed to measure the mass hygroscopic growth factors of KClO 4 at 278 K. No significant change in sample mass was observed when RH was increased from 0% to 95%, suggesting that the DRH of KClO 4 was >95%. Additional experiments were carried out at 298 K, and the DRH of KClO 4 was also found to be >95% at 298 K. 42 suggests that for a given perchlorate concentration in molality (mol kg À1 ), water activity of Mg(ClO 4 ) 2 solution is slightly larger than that for Ca(ClO 4 ) 2 . Since water activity decreases with solute concentration, this implies that for a given water activity, the molality concentration is smaller for Mg(ClO 4 ) 2 .…”

Section: Mass Hygroscopic Growth Factors Of Perchloratesmentioning

confidence: 91%

“…Since water activity decreases with solute concentration, this implies that for a given water activity, the molality concentration is smaller for Mg(ClO 4 ) 2 . In other words, the theoretical work by Toner et al 42 also suggested that at a given RH more water is associated with Mg(ClO 4 ) 2 than Ca(ClO 4 ) 2 on the per mole ClO 4 À base.…”

Section: Mass Hygroscopic Growth Factors Of Perchloratesmentioning

confidence: 97%

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Water uptake and hygroscopicity of perchlorates and implications for the existence of liquid water in some hyperarid environments

Tang

et al. 2017

RSC Adv.

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Section: Mass Hygroscopic Growth Factors Of Perchloratesmentioning

confidence: 91%

Section: Mass Hygroscopic Growth Factors Of Perchloratesmentioning

confidence: 97%

Water uptake and hygroscopicity of perchlorates and implications for the existence of liquid water in some hyperarid environments

Tang

et al. 2017

RSC Adv.

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“… Calculated activity of supercooled water on ice curve compared to activity using eq 10 to equilibrium constants by Murphy and Koop 36 and Spencer et al 32 as well as polynomial equation with six terms by Carslaw et al 42 and Toner et al 1 …”

Section: Vapor Pressurementioning

confidence: 99%

Activity of Supercooled Water on the Ice Curve and Other Thermodynamic Properties of Liquid Water up to the Boiling Point at Standard Pressure

Sippola

Taskinen

2018

J. Chem. Eng. Data

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A simple model for thermodynamic properties of water from subzero temperatures up to 373 K was derived at ambient pressure. The heat capacity of supercooled water was assessed as lambda transition. The obtained properties for supercooled water such as heat capacity, vapor pressure, density and thermal expansion are in excellent agreement with literature data. Activity of water on ice curve, independent of used electrolyte and Debye−Hückel constant applied in modeling, is also calculated. Thus, the ice curve activity of supercooled water can be used as a universal basis for thermodynamic modeling of aqueous solutions, precipitating hydrated and anhydrous solids. A simple model for heat capacity, density and thermal expansion of ice are also derived from 170 K up to melting point.

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“…Many recent studies have examined the deliquescence, efflorescence, or freezing of pure perchlorate salts or brines (Fischer et al, , ; Gough et al, ; Nikolakakos & Whiteway, ; Nuding et al, ; Primm et al, ; Toner et al, ). The low‐temperature phase transition behavior of many pure perchlorates is therefore fairly well established.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Mars‐Relevant Soil Analogs on the Water Uptake of Magnesium Perchlorate and Implications for the Near‐Surface of Mars

et al. 2018

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The water uptake and release by perchlorate salts have been well studied since the first in situ identification of such salts in the Martian soil by the Phoenix mission in 2008. However, there have been few studies on the effect of the insoluble regolith minerals on the interaction of perchlorate with water vapor. In this work, we investigate the impact of a Mars-relevant mineral, montmorillonite, and a Mars soil analog, Mojave Mars Simulant (MMS), on the deliquescence (transition from dry crystalline to aqueous via water vapor absorption), ice formation, and efflorescence (transition from aqueous to dry crystalline via loss of water) of pure magnesium perchlorate. We studied mixtures of magnesium perchlorate hexahydrate with either montmorillonite or MMS. Although montmorillonite and MMS are materials that may serve as nuclei for either ice nucleation or salt efflorescence, we find that these soil analogs did not affect the phase transitions of magnesium perchlorate. The salt-mineral mixture behaved similarly, within estimated uncertainties, to pure magnesium perchlorate in all cases. Experiments were performed in both N 2 and CO 2 atmospheres, with no detectable difference. We use data from the Mars Science Laboratory Rover Environmental Monitoring Station instrument and the Phoenix Thermal and Electrical Conductivity Probe, as well as modeling of the shallow subsurface, to determine the likelihood of these perchlorate phase transitions occurring at Gale Crater and the northern arctic plains (Vastitas Borealis). We find that aqueous solutions are predicted in the shallow subsurface of the Phoenix landing site, but not predicted at Gale Crater. Plain Language SummaryMost previous studies on Mars-relevant salts have looked at the water uptake and release of the pure salts, but few have looked at the effect that insoluble minerals might have on the water uptake and release. This is an important potential effect because the surface of Mars is mainly composed of (~99%) mineral dust and we might not be accurately predicting if liquid solutions are possible on Mars today. However, this study shows that a Mars-relevant mineral (montmorillonite) and a Mars surface analog (Mojave Mars Simulant) did not have a significant effect on the water uptake of magnesium perchlorate. In addition, the Phoenix landing site is more favorable to support liquid solutions of magnesium perchlorate, rather than Gale Crater (Curiosity's current site).Deliquescence is the transition that occurs when a dry crystalline particle absorbs water vapor and turns into an aqueous droplet, while efflorescence is the opposite phase transition where an aqueous drop loses water PRIMM ET AL.2076 Hogancamp, J. V., et al. (2018). The effect of Mars-relevant soil analogs on the water uptake of magnesium perchlorate and implications for the near-surface of Mars.

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A revised Pitzer model for low-temperature soluble salt assemblages at the Phoenix site, Mars

Cited by 37 publications

References 65 publications

Water uptake and hygroscopicity of perchlorates and implications for the existence of liquid water in some hyperarid environments

Water uptake and hygroscopicity of perchlorates and implications for the existence of liquid water in some hyperarid environments

Activity of Supercooled Water on the Ice Curve and Other Thermodynamic Properties of Liquid Water up to the Boiling Point at Standard Pressure

The Effect of Mars‐Relevant Soil Analogs on the Water Uptake of Magnesium Perchlorate and Implications for the Near‐Surface of Mars

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