Abstract
In a previous publication, we studied mass transfer at a rotating disk electrode in "inert" particle suspensions. We now account for the variations of the limiting diffusion current with numerous parameters by different phenomena. These involved either the topography of the interface through adhesion of the particles to the electrode or the mass exchanges in the diffusion layer through changes in the velocity field and/or diffusion coefficient. Each phenomenon, considered separately, gives rise to one or more linear segments for the variations of current with the rotation speed Ω, in logarithmic coordinates. Considering all the invoked phenomena, we would expect more segments than the four observed in experimental
vs. 
plots. Analyzing the consequences of each phenomenon in the whole Ω range allows one to disregard some of them for certain Ω values and to account for most of the experimental results. At low Ω values, two predominant phenomena, with antagonistic effects, explain the deviations from the one‐phase media behavior: the reduction of the exchange area and the increase of the apparent diffusion coefficient through changes in the size of aggregates along the streamlines. Moreover, for small‐size particles or for particle concentrations sufficiently high, deviations from newtonian behavior are also observed. At intermediate and high Ω values, the predominant phenomenon is the variation of the diffusion coefficient with the shear rate. Depending on the ratio of the diffusion layer thickness over the particle size (δ/α), two different laws can describe this variation.