Characterization of the membrane charge of Al2O3 membranes

In order to characterize the membrane charge of the alumina membrane, we saw about the information on the membrane charge at first. Then, we pointed out that the effective membrane charge of alumina consists of two parts. One part is the membrane charge due to the dissociation of the ionizable groups of membrane, and the other part is the membrane charge affected by the electrolytes in the bulk solution. Then, we proposed the new membrane model that is the combination of the selective ion adsorption model and the amphoteric membrane model. In this model, the effective membrane charge is determined by the dissociation of the ionizable groups of the membrane and the selective adsorption of ions. We theoretically discussed the effect of the electrolyte concentration, the ionic species and the pH on the effective membrane charge, Then, we showed that this new model, the advanced amphoteric membrane model, can qualitatively explain the phenomena related to the membrane charge. We applied the advanced amphoteric membrane model to the membrane potential of alumina membrane and concluded that the effective membrane charge of the alumina membrane was determined by the dissociation of the ionizable groups and the adsorption of anions. (C) 2001 Elsevier Science B.V. All rights reserved.