Etude du transport de matiere en solution, a l'aide des electrodes a disque et a anneau tournants

Abstract

In diluted solutions, the Levitch theory about the convective diffusion in a laminar regime is verified up to Reynolds number of 2.7 × 10 −5. In a turbulent regime an expression for the limiting flux of diffusion, whence we can infer the value of a characteristic constant of the mass transfer, is found. It is pointed out that these results are no longer valuable when the surface of the electrode is no longer smooth. In concentrated solutions, we take variation with the concentration of the density, the viscosity and the diffusion coefficient, into account, and we show that, in a laminar regime, the density of the limiting diffusion current remains proportional to the square root of the angular velocity of the electrode. We take then into account the existence of a temperature gradient and we determine the conditions according to which the preceding result remains valuable. The reckoning method is applied to electrodes of different geometries and we give a few examples of applications to the anodic dissolution of metals.