ELECTRIC FIELD-ASSISTED PROTON-TRANSFER AND WATER DISSOCIATION AT THEJUNCTION OF A FIXED-CHARGE BIPOLAR MEMBRANE

Electric field-enhanced (EFE) water dissociation can occur at the inte rfacial space charge junction of both biological and synthetic fixed-c harge bipolar membranes. This dissociation has so far been analysed on an electrochemical basis using modified second Wien effect and absolu te rate theories. We propose a statistical thermodynamics model to des cribe the cooperative orientation of the water molecules by the electr ic field at the bipolar junction. The approach is simple and retains s ome of the essential aspects of the phenomenon. In particular, the EFE water dissociation can now be rationalised on the basis of a field-as sisted proton transfer mechanism involving the membrane fixed charge a nd the water molecules at the space charge region of the bipolar junct ion. (C) 1998 Elsevier Science B.V. All rights reserved.