Activity coefficients in sea water using Monte Carlo simulations

Lund, Mikael; Jönsson, Bo; Pedersen, Thorvald

doi:10.1016/s0304-4203(02)00039-7

Cited by 25 publications

(12 citation statements)

References 22 publications

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“…(9) is that the refractive index, the density, and the activity for seawater have all been measured with high precision as a function of salinity. The activity for seawater was recently estimated using a Monte Carlo simulation [30], the results agree with the experimental values [20] Table 1, which also listed the formulae for the other parameters in Eqs (2) and (9).…”

Section: Introductionsupporting

confidence: 67%

Scattering by pure seawater: Effect of salinity

2009

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A theoretical model was developed estimating the scattering by seawater that are due to concentration fluctuation. Combining with the model proposed for density fluctuation (Optics Express, 17, 1671, 2009), we evaluated the overall effect of sea salts on the scattering. The variation of seawater scattering with the salinity is a combination of two factors: decreasing contribution due to density fluctuation and increasing contribution due to concentration fluctuation, with the latter effect dominating. The trend is, however, slightly non-linear and the linear adjustment of scattering with salinity that is frequently used would lead to an underestimate by an average of 2%. The results estimated at S = 38.4 per thousand agree with the measurements by Morel (Cahiers Oceanographiques, 20, 157, 1968) with an average difference of 1%, well within his experimental error of 2%. The spectral signature also varies with salinity, with the power-law slope increasing from -4.286 to -4.306 for salinity from 0 to 40 per thousand.

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Section: Introductionsupporting

confidence: 67%

Scattering by pure seawater: Effect of salinity

2009

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“…This property is typically derived from a thermodynamic model such as Pitzer's [65], with the model itself fit to vapor pressure data or boiling point elevation data. In the literature, the activity of water in seawater was reported previously by Bromley et al [33] and by Lund et al [66]. Bromley et al, calculated activity using a model fit to boiling point elevation data and reported data for 0 ≤ t ≤ 200 °C and 10 ≤ S ≤ 120 g/kg while Lund used statistical mechanics to calculate activity for t = 25 °C and 5 ≤ S ≤ 35 g/kg.…”

Section: Appendix D Activity Of Water In Seawatermentioning

confidence: 96%

Thermophysical properties of seawater: A review and new correlations that include pressure dependence

et al. 2016

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In a previous paper, the authors have given correlations for seawater thermophysical properties as functions of temperature and salinity, but only for near atmospheric pressures. Seawater reverse osmosis (SWRO) systems operate routinely at pressures of 6 MPa or more; however, experimental data for seawater properties at elevated pressures (P = 0.1-12 MPa) are limited to a salinity of 56 g/kg. To accurately model and design SWRO and thermal desalination systems, a reliable method of estimating the effect of pressure on seawater properties is required. In this work, we present this method and new correlations for seawater thermophysical properties that are valid within the range: t = 0-120 °C, S = 0-120 g/kg, and P = 0-12 MPa. Seawater isothermal compressibility data, available until a salinity of 56 g/kg, were used to develop a correlation for compressibility that is extrapolated to 160 g/kg. Thermodynamic identities were then used to develop accurate pressure dependent correlations for seawater: density, isobaric expansivity, specific heat capacity, enthalpy, entropy and Gibbs energy. New correlations were proposed for 2 surface tension and osmotic coefficient were reviewed. Uncertainty bounds were calculated for each correlation.

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“…The departure from ideality (γ = 1) is nonnegligible and as a consequence the dissolution of CO 2 in sea water is significantly larger than in fresh water. The excellent agreement between measured and simulated activity factors in Table 1 0.14 0.15 Table 1: Experimental [5,6] and simulated [7] mean activity factors in sea water at 298 K. The salinity is 3.5 %.…”

Section: A Simple Electrolyte Solutionmentioning

confidence: 75%

Chapter 9. Electrostatics in Macromolecular Solutions

Jönsson¹,

Lund²,

Silva³

Food Colloids

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An overview of the interaction between charged macromolecules in aqueous solution is presented. The starting point is the dielectric continuum model and the Debye-Hückel equation. The usefulness of the simple theory is emphasized in particular for biological macromolecules, whose net charge or surface charge density often is low. With more highly charged macromolecules or aggregates it may be necessary to go beyond the simple Debye-Hückel theory and invoke the non-linear Poisson-Boltzmann equation or even to approach an exact solution using Monte Carlo simulations or similar techniques. The latter approach becomes indispensable when studying systems with divalent or multivalent (counter)-ions. The long range character of the electrostatic interactions means that charged systems of varying geometry -spheres, planes, cylinders... -often have many properties in common. Another consequence is that the detailed charge distribution on a macromolecule is less important. Many biological macromolecules contain titratable groups, which means that the net charge will vary as a consequence of solution conditions. This gives an extra attractive contribution to the interaction between two macromolecules, which might be particularly important close to their respective isoelectric points. The treatment of flexible polyelectrolytes/polyampholytes requires some extra efforts in order to handle the increasingly complex geometry. A theoretical consequence is that the number of parameters -chain length, charge density, polydispersity etc -prohibits the presentation of a simple unified picture. An additional experimental, and theoretical, difficulty in this context is the slow approach towards equilibrium, in particular with high molecular weight polymers. A few generic situations where polyelectrolytes can act both as stabilizers and coagulants can, however, be demonstrated using simulation techniques.

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Activity coefficients in sea water using Monte Carlo simulations

Cited by 25 publications

References 22 publications

Scattering by pure seawater: Effect of salinity

Scattering by pure seawater: Effect of salinity

Thermophysical properties of seawater: A review and new correlations that include pressure dependence

Chapter 9. Electrostatics in Macromolecular Solutions

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