Measurement and Correlation of Surface Tension for Single Aqueous Electrolyte Solutions

In this study, the values of the surface tension for a number of single aqueous electrolyte solutions were measured at various temperatures and electrolyte concentrations using the well-known and computer-aided pendant-drop method. In order to conduct the experimental measurements, a high-pressure IFT-700 apparatus, equipped with a view cell and a data acquisition system, was used. The systems studied in this study were aqueous solutions of KCl, NaCl, CaCl2, and Na2SO4. The pooled standard deviation and the confidence limit of the surface-tension data for a 95% confidence level were determined to be 0.17mN . m(-1) and (sigma) over bar +/- 0.19, respectively. It should be noted that while the surface tension for electrolyte solutions increases as the electrolyte concentration increases, it decreases with an increase in temperature as expected. Finally, data reduction was carried out using an empirical equation to show the effect of temperature, electrolyte concentration, and the nature of ionic species on the surface tension for the systems studied.