The electroadsorption of alumina particles on fibrous carbon and graphite electrodes

The potential dependent adsorption of alumina particles on carbon and graphite fibrous electrodes is studied. Marked differences in the effect of potential on the adsorption rates and saturation capacities among graphite, carbon, and acid-treated carbon electrodes are found. These differences are interpreted in terms of the location of the PZC of each electrode on the potential scale and the charge on the particles. At the open circuit potentials, a maximum in the adsorption rate is observed below the isoelectric pH value. Also, the adsorption rates on the graphite are significantly larger than those on the carbon electrodes. These phenomena are related to the response of the surface groups on the electrodes to pH variations as well as to the stability of the suspension.