Water activity data representation of aqueous solutions at 25°C

Abstract

Polynomial expressions have been fitted to the complete range of available water‐activity data for 396 electrolyte and non‐electrolyte aqueous binary systems. The standard deviation of regression rarely exceeded 0.001 and was less than 0.0002 in most cases. Such data representation is useful for the prediction of the water‐activity of mixed moderately concentrated aqueous solutions.

Influence of salt concentration on DCMD performance for treatment of highly concentrated NaCl, KCl, MgCl2 and MgSO4 solutions

“…3, which follows the order of MgSO 4 N KCl N NaCl N MgCl 2 at the concentrations higher than 1.0 mol/L. It can be observed that the predicted values are in good agreement with experimental data measured by Teng and Lenzi [22] in the concentration range in question. Interestingly, MgCl 2 shows a distinct difference compared to NaCl, KCl and MgSO 4 .…”

Evaluation of Norrish’s Equation for Correlating the Water Activity of Highly Concentrated Solutions of Sugars, Polyols, and Polyethylene Glycols

“…a predicted using the literature's K value; b predicted using the K value calculated from all experimental data. Experimental data: empty circles, Scatchard et al (1938); filled diamonds, Teng and Lenzi (1974); filled triangles, Bubnik et al (1995) very good up to about 60% concentration; however, above this value, deviations were quite important. Predictions made using K values calculated from experimental data from low to high concentrations were not sufficient to improve modeling of data for the whole curve.…”

“…a Predicted using the literature's value of K; b predicted using the K value calculated from all experimental data. Experimental data: x symbol, Teng and Lenzi (1974); filled triangles, Comesaña et al (2001); filled diamonds, Ninni et al (2000); empty circles, Peng et al (2001) Fructose, 25°C Fig. 2 a Comparison of predicted and experimental a w data for fructose solutions at 25°C.…”

“…a Predicted using the literature's "most accepted" value of K; b predicted using K value calculated from all experimental data. Experimental data: filled triangles, Scatchard et al (1938); x symbol, Teng and Lenzi (1974); filled diamonds, Ninni et al (2000); empty circles, present work. b Predicted a w data for xylitol solutions at 25°C predicted using the literature's value of K. Experimental data: empty circles, Comesaña et al (2001); filled diamonds, Ninni et al (2000).…”

Equation for solvent activity correlation in ternary solutions with electrolyte and molecular components

“…In these cases, the activity of the solvent can be evaluated directly from the corresponding solution vapour pressure and thus the experimental dependence of the solvent activity on composition a 1 (m 2 , m 3 ) is obtained. To describe these systems, binary or ternary, it is usual to employ polynomial expressions [1][2][3][4][5][6][7][8][9][10][11], which are used independently of the nature of the solution. The problem is that the first terms of the polynomial are strongly dependent on the nature of the system and consequently, in most cases these expressions are not thermodynamically consistent, as they do not satisfy the limiting behavior required by the Thermodynamics of solutions.…”