Osmotic coefficient and mean ion activity coefficient of NiCl2 aqueous solution at several temperatures

2016 ◽  
Vol 100 ◽  
pp. 72-78 ◽  
Author(s):  
Peikang Dai ◽  
Huaqiang Huang ◽  
Zhiying Ding ◽  
Yaning He ◽  
Shijun Liu
Keyword(s):  
Aqueous Solution ◽  
Activity Coefficient ◽  
Osmotic Coefficient ◽  
Ion Activity

Speciation and Geochemical Implications of Carcass Burial Leachate

2018 ◽  
Vol 61 (2) ◽  
pp. 559-570
Author(s):  
Dyan L. Pratt ◽  
Terrance A. Fonstad
Keyword(s):  
Chemical Composition ◽  
Ionic Strength ◽  
Activity Coefficient ◽  
Swine Manure ◽  
Burial Site ◽  
Mass Mortality Event ◽  
Ammonium N ◽  
Ion Activity ◽  
Common Activity ◽  
The Impact

Abstract. In the event of a mass livestock mortality situation, disposal routes such as burial are commonly chosen. The impact of burial on the environment could be substantial, but the composition of the leachate arising from a burial site has not been well documented. This study was performed to determine the chemical composition of leachate arising from animal mortalities in a burial setting. Three species of livestock were used: bovine, swine, and poultry. Leachate collected from lined burial pits over two years of decomposition was analyzed for major and minor ions. Analysis indicated that livestock mortality leachate contains, on average, concentrations of 46,000 mg L-1 of alkalinity (as bicarbonate), 12,600 mg L-1 of ammonium-N, 2600 mg L-1 of chloride, 3600 mg L-1 of sulfate, 2300 mg L-1 of potassium, 1800 mg L-1 of sodium, and 1500 mg L-1 of phosphorus, along with lesser amounts of iron, calcium, and magnesium. Select samples had maximum concentrations of ammonium-N and bicarbonate up to 50% higher than these average values. In comparison to earthen swine manure storages and landfills, the ionic strength of the leachate was 2 to 4 times higher, and therefore its impact on water resources could be greater. Following the study of the chemical composition of livestock mortality leachate, the potential impacts of this leachate on the soil/water systems below a burial site were investigated. The ionic strength of the leachate presents its own set of challenges. Basic modeling of ion activity using the five most common activity coefficient equations (Debye-Hückel, extended Debye-Hückel, Truesdell-Jones, Davies, and Pitzer) were considered to assess the sensitivity of these methods for calculated ion activity as impacted by the ionic strength of the leachate. This was completed to further enhance the modeling and speciation efforts. Based on the results and the applicability of the Truesdell-Jones equation, PHREEQC was used to assess the chemical speciation of the leachate. The speciation of this leachate provides evidence of phosphate and sulfate compounds available for potential unattenuated transport. Understanding the geochemical implications of livestock mortality burial will give scientists and regulators more information for performing future risk analyses when considering mortality burial as a management option, either routinely or during a mass mortality event. Keywords: Ion activity coefficient, Ionic strength, Leachate chemical composition, Livestock burial leachate, Speciation.

Which value for the first dissociation constant of carbonic acid should be used in biological work?

1991 ◽  
Vol 260 (5) ◽  
pp. C1113-C1116 ◽  
Author(s):  
R. W. Putnam ◽  
A. Roos
Keyword(s):  
Ionic Strength ◽  
Activity Coefficient ◽  
Dissociation Constant ◽  
Carbonic Acid ◽  
Mass Action ◽  
Bicarbonate Concentration ◽  
Apparent Dissociation Constant ◽  
Logarithmic Form ◽  
Ion Activity ◽  
Hasselbalch Equation

The apparent first dissociation constant of carbonic acid has been defined in different ways in the literature. Harned and co-workers (8-10) have defined it in terms of molalities of the participating species, including H ions: Ks = mHmHCO3/mCO2. In contrast, Hastings and Sendroy have defined an apparent constant in which acidity is expressed as H ion activity: K'1 = aHmHCO3/mCO2. These constants differ by a factor gamma H, the activity coefficient of H ions at the prevailing ionic strength. Therefore, pK'1 is greater than pKs by an amount equal to -log gamma H, which, at mu = 0.16 M, is approximately 0.1. It is important that the correct value for the apparent dissociation constant or its logarithmic form be entered in the mass action expression or in the Henderson-Hasselbalch equation in order to prevent significant errors in the computation by means of these equations of quantities that cannot be directly measured. Specifically, for the derivation of bicarbonate concentration from PCO2 and pH (-log aH), pK'1 is to be used and not an uncorrected pKs.

The diffusion of electrolytes in a cation-exchange resin membrane I. Theoretical

1955 ◽  
Vol 232 (1191) ◽  
pp. 498-509 ◽  
Keyword(s):  
Aqueous Solution ◽  
Activity Coefficient ◽  
Cation Exchange ◽  
Exchange Resin ◽  
Volume Fraction ◽  
Cation Exchange Resin ◽  
Physical Nature ◽  
Concentration Difference ◽  
Flow Through ◽  
Resin Membrane

An equation for the flux of electrolyte through a water-swollen cation-exchange resin membrane separating two solutions of the same electrolyte at different concentrations is derived on the basis of several assumptions regarding the physical nature of a swollen resinous exchanger. The complete flux equation contains three terms, one determined by the concentration difference across the membrane, another determined by the variation of the activity coefficient of the electrolyte with concentration in the membrane and a third concerned with the rate of osmotic or hydrostatic flow through the membrane. If ions in the resin are transported entirely in an internal aqueous phase, the mobilities required for the flux equation can be related to mobilities in aqueous solution and to the volume fraction of resin in the swollen membrane. The treatment is readily extended to anion exchangers.

Ionic association in aqueous solutions of bivalent sulphates

1969 ◽  
Vol 313 (1512) ◽  
pp. 131-147 ◽  
Keyword(s):  
Aqueous Solution ◽  
Osmotic Coefficient ◽  
Dissociation Constants ◽  
Divalent Cations ◽  
Ion Pairs ◽  
Osmotic Coefficients ◽  
Close Approach ◽  
Complete Analysis ◽  
Hydration Water ◽  
Similar Magnitude

Osmotic coefficient data for the sulphates of Mg, Ca, Zn, Ni and Cu in aqueous solution have been analysed to obtain the dissociation constants (d.c.) of ion pairs, triplets and quadruplets, as well as information on their state of hydration. The d.c.’s of the sulphate ion pairs, though of similar magnitude, show distinct individualities, and the trend is similar to that of the d.c.’s calculated for the nitrates of di-valent ions, though the d.c.’s of the latter are about 200 times larger. The d.c.’s of the ion triplets show no correlations, but their absolute values are similar to those calculated from the theory of Fuoss & Kraus (1933, 1935) based on electrostatic considerations. The hydration parameters of the associated sulphates (both pairs and triplets), as characterized in the linear (statistical) terms of the osmotic coefficients, are only slightly smaller than those of the fully dissociated electrolytes, indicating that there is only little loss of hydration water in the process of association, in spite of the heavy hydration of the divalent cations and the relatively close approach of the sulphate ion. The complete analysis of the osmotic coefficient curves makes it possible to calculate the absolute values of the activity coefficients of the divalent sulphates (previously not known to any accuracy).

Activity Coefficient of the Magnesium Ion in Sea Water

1965 ◽  
Vol 22 (1) ◽  
pp. 113-116 ◽  
Author(s):  
R. F. Platford
Keyword(s):  
Activity Coefficient ◽  
Sodium Hydroxide ◽  
Sea Water ◽  
Magnesium Ion ◽  
Activity Product ◽  
Hydroxyl Ion ◽  
Ion Activity ◽  
Total Magnesium

Sodium hydroxide was added to carbonate-free sea water and the point at which Mg(OH)2 precipitated was detected optically. At this point the hydroxyl ion activity was calculated from the measured pH of the solution and the magnesium ion activity was calculated from the activity product for Mg(OH)2.From a knowledge of the magnesium ion activity and other data, it was estimated that about 3% of the total magnesium in the sea water was in the form of [Formula: see text].

Molecular simulation of osmometry in aqueous solutions of the BMIMCl ionic liquid: a potential route to force field parameterization of liquid mixtures

2020 ◽  
Vol 22 (48) ◽  
pp. 28325-28338
Author(s):  
Debdas Dhabal ◽  
Tanmoy Patra
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Ionic Liquid ◽  
Aqueous Solutions ◽  
Force Field ◽  
Molecular Simulation ◽  
Osmotic Coefficient ◽  
Force Fields ◽  
Liquid Mixtures ◽  
Force Field Parameterization

By means of molecular simulation, the osmotic coefficient of aqueous solution of BMIMCl ionic liquid is calculated to compare with the experimental data and use that to optimize two popular force fields available in the literature for bulk ILs.

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