Coupled Transport of Metal Ions in Aqueous Solutions Containing NaCl and HCl

Abstract

The main objective of this work was to analyze the transport by diffusion of salts containing some metal ions (that is, CoCl2, CrCl3, HgCl2, and PbCl2), at 25.0 °C, in two different aqueous solutions with varying pH levels, namely, sodium chloride and hydrochloric chloride, by using Nernst–Hartley model equations. To analyze the applicability of this model, experimental data for two aqueous systems (CoCl2 + NaCl) and (CoCl2 + HCl), were obtained by using the Taylor technique and compared with the predicted values. The Nernst–Hartley model equations were used in this study to estimate the mutual diffusion coefficients of the eight ternary systems, which included (CoCl2 + NaCl), (HgCl2 + NaCl), (PbCl2 + NaCl), (CrCl3 + NaCl), and (CoCl2 + HCl), (HgCl2 + HCl), (PbCl2 + HCl), and (CrCl3 + HCl). By using the limiting equations of Nernst–Hartley coefficients, we were able to understand the composition dependence of the mutual diffusion coefficients of these mixed electrolyte solutions and the electrostatic mechanism for the strongly coupled diffusion of these components.