ELECTRICAL POTENTIAL BETWEEN DISSIMILAR CLAY DOUBLE LAYERS

Abstract A model describing the electric double layers in clay-electrolyte systems containing particles with different surface charge densities was developed and used to calculate the film thickness of water present in a clay paste. The average water film thicknesses (-18/~) calculated by considering the clay to contain 9 groups of particles of different charge densities did not differ from those calculated by assuming one average charge density; provided the minimum potential between particles remained constant. These values, however, were higher than those obtained from gravimetric water determinations by about 30%. The overestimation f the average thickness of the water films by the theoretical model is most likely due to the assumption ofa complete parallel arrangement of particles in the paste and the validity of the Gouy theory for double layers on clays