Diffusion Coefficients for Copper (II) in Aqueous Cupric Sulfate‐Sulfuric Acid Solutions

Abstract

Diffusion coefficients for Cu(II), , were determined at 25°C in over the concentration range . The reported values of represent average values for the physical properties over the diffusion layer, and for the diffusing Cu(II) species, which consist of Cu++ ions and ion pairs. Thus, represents an effective value that is suitable for substitution into the various mass‐transfer equations derived by assuming constant properties. At low concentrations (0.4–6 mM) static mercury drop electrode (SMDE) polarography using a modified version of the Cottrell equation with a spherical correction term was used to determine . At higher concentrations was determined chronopotentiometrically using the Sand equation. The values of in 0.51M aqueous at 25°C were as follows