Individual Ionic Activity Coefficients of Sodium Halides in Glucose

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Comment on “Individual Ionic Activity Coefficients of Sodium Halides in Glucose Water Solutions at 298.15 K” Francesco Malatesta* Dipartimento di Chimica e Chimica Industriale dell’Universita di Pisa, Via Risorgimento 35, 56136 Pisa, Italy

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eiyan Dong, Yang Zhao, Kelei Zhuo, and Yujuan Chen recently published a paper in this Journal,1 in which they provide purported values of individual ionic activity coefficients of sodium halides in glucose water solutions. Their results rely on the same experimental method and basic hypotheses of a previous paper.2 However, it has been demonstrated that results so obtained have no relation to individual ionic activity coefficients; they are only associated with mean activity coefficients and transport numbers of the ions.3 Dong et al.1 were perfectly aware of this fact, because that information (in ref 3) was made available to them before their manuscript was definitely revised. Yet, they neither mentioned this circumstance nor reported the corresponding literature (ref 3) inside their paper. Therefore, a warning is strictly necessary: the quantities reported as “individual ionic activity coefficients” in the work of Dong et al.1 have no relation to the individual ionic activity coefficients—which remain undefined—and have no scientific or practical value.

’ AUTHOR INFORMATION Corresponding Author

*E-mail address: [email protected].

’ REFERENCES (1) Dong, W.; Zhao, Y.; Zhuo, K.; Chen, Y. Individual Ionic Activity Coefficients of Sodium Halides in Glucose Water Solutions at 298.15 K. Ind. Eng. Chem. Res. 2010, 49, 9430–9433. (2) Zhuo, K.; Dong, W.; Wang, W; Wang, J. Activity coefficients of individual ions in aqueous solutions of sodium halides at 298.15 K. Fluid Phase Equilib. 2008, 274, 80–84. (3) Malatesta, F. Activity coefficients of ions in sodium halide solutions: critical remarks. Fluid Phase Equilib. 2010, 295, 244–248.

Published: June 23, 2011 r 2011 American Chemical Society

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dx.doi.org/10.1021/ie200302q | Ind. Eng. Chem. Res. 2011, 50, 9471–9471