A chemical model for sea water at 25 degrees C and one atmosphere total pressure

Garrels, Robert M.; Thompson, Michelle E.

doi:10.2475/ajs.260.1.57

Cited by 530 publications

(199 citation statements)

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“…(4), from the computed PMFs is a sensitive test of the methods and provides one of the few ways to probe CIP/SSIP distributions in solution. The calculated association constants K a of the cation -carboxylic group ion pairs are listed in Table 5, and the values of the equilibrium constants K eq are listed in [89][90][91][92][93] with which the computed results should be compared (Table 5). The evaluation of these experimental differences is beyond the scope of this paper.…”

Section: Potentials Of Mean Force Association and Equilibrium Constamentioning

confidence: 99%

Metal Cation Complexation with Natural Organic Matter in Aqueous Solutions: Molecular Dynamics Simulations and Potentials of Mean Force

Iskrenova-Tchoukova¹,

Kalinichev²,

2010

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Natural organic matter (NOM, or humic substance) has a known tendency to form colloidal aggregates in aqueous environments, with the composition and concentration of cationic species in solution, pH, temperature, and the composition of the NOM itself playing important roles. Strong interaction of carboxylic groups of NOM with dissolved metal cations is thought to be the leading chemical interaction in NOM supramolecular aggregation.Computational molecular dynamics (MD) study of the interactions of Na + , Mg 2+ , and Ca 2+ with the carboxylic groups of a model NOM fragment and acetate anions in aqueous solutions provides new quantitative insight into the structure, energetics, and dynamics of the interactions of carboxylic groups with metal cations, their association and the effects of cations on the colloidal aggregation of NOM molecules. Potentials of mean force and the equilibrium constants describing overall ion association and the distribution of metal cations between contact ion pairs and solvent separated ions pairs were computed from free MD simulations and restrained umbrella sampling calculations. The results provide insight into the local structural environments of metal-carboxylate association and the dynamics of exchange among these sites. All three cations prefer contact ion pair to solvent separated ion pair coordination, and Na + and Ca 2+ show a strong preference for bidentate contact ion pair formation. The average residence time of a Ca 2+ ion in a contact ion pair with the carboxylic groups is of the order of 0.5 ns, whereas the corresponding residence time of a Na + ion is only between 0.02 and 0.05 ns. The average residence times of a Ca 2+ ion in a bidentate coordinated contact ion pair vs. a monodentate coordinated contact ion pair are about 0.5 ns and about 0.08 ns, respectively. On the 10-ns time scale of our simulations, aggregation of the NOM molecules occurs in the presence of Ca 2+ but not Na + or Mg 2+ . These results agree with previous experimental observations and are explained 3 by both Ca 2+ ion-bridging between NOM molecules and decreased repulsion between the NOM molecules due to the reduced net charge of the NOM-metal complexes. Simulations on a larger scale are needed to further explore the relative importance of the different aggregation mechanisms and the stability of NOM aggregates.4

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Section: Potentials Of Mean Force Association and Equilibrium Constamentioning

confidence: 99%

Metal Cation Complexation with Natural Organic Matter in Aqueous Solutions: Molecular Dynamics Simulations and Potentials of Mean Force

Iskrenova-Tchoukova¹,

Kalinichev²,

2010

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“…The first of these has been the application of chemical equilibrium models to the composition of seawater (Sillen, 1961;Garrels and Thompson, 1962;Lafon and Mackenzie, 1974). This method allows the time-invariant system to be modelled from the thermodynamic properties of the constituent phases.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal alteration of oceanic basalts by seawater

Humphris

1978

Geochimica et Cosmochimica Acta

488

138

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“…A chemical model for sea water was presented by Garrels to assess the percentages of the major dissolved species [20], however, due to the super high ionic strength of brine, it is inapplicable to use this model into salt lake brine system without parameter correction. In the 1980s, Harive and Wear recompiled the Pitzer electrolyte thermodynamic calculation formula [21,22] as follows: …”

Section: Lithium Occurrence Status During Brine Evaporationmentioning

confidence: 99%

Migration Behavior of Lithium during Brine Evaporation and KCl Production Plants in Qarhan Salt Lake

Song

Gang

et al. 2017

Minerals

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Lithium-brine is an important potential source of lithium. Much research and investigation has been carried out aimed at lithium recovery from brine. Although the distribution and occurrence status of lithium in brine have important implications for lithium recovery, few reports had correlated to this issue. In this article, a study was carried out to explore the lithium migration behavior during brine evaporation and KCl production process at Qarhan Salt Lake. The occurrence status of lithium both in fresh mined brine and residual brine after evaporation were also speculated by means of lithium concentration evaluation and theoretical calculation based on the Pitzer electrolyte solution theory. Results showed that, for Qarhan brine mined from the Bieletan region, most lithium was enriched in the residual brine during the brine evaporation process. The concentration of lithium in the residual brine could be more than 400 mg/L. More than 99.93% lithium ions in residual brine exist in free ions state and lithium does not precipitate from brine with a density of 1.3649 g/mL. The results also revealed that lithium concentration in wastewater discharged from KCl plants can reach a level of 243.8 mg/L. The investigation results provide a theoretical basis for comprehensive development and utilization of lithium resources in Qarhan Salt Lake.

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A chemical model for sea water at 25 degrees C and one atmosphere total pressure

Cited by 530 publications

References 0 publications

Metal Cation Complexation with Natural Organic Matter in Aqueous Solutions: Molecular Dynamics Simulations and Potentials of Mean Force

Metal Cation Complexation with Natural Organic Matter in Aqueous Solutions: Molecular Dynamics Simulations and Potentials of Mean Force

Hydrothermal alteration of oceanic basalts by seawater

Migration Behavior of Lithium during Brine Evaporation and KCl Production Plants in Qarhan Salt Lake

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