An Electrode System For Transient Dispersion Studies in Unsaturated Glass Bead Medium

Despite the present emphasis on need for understanding the coupled transport of water and solute in soils, few investigations have dealt with salt and water movement in partially saturated porous systems. The movement of chloride ions has been studied using silver-silver chloride electrodes with high input impedance potentiometer. The solution content of the porous medium was varied from saturation to about half saturation, and a wide range of seepage velocities was used. The electrolyte solutions were combinations of potassium chloride andpoltassium nitrate, with a total ionic strength of O.IN, to minimize any solutions density and streaming potential effects. The e.m.f. output of the electrodes was not affected by the degree of saturation of the bed within the range of seepage velocities tested. The response lime of the electrodes at various solution contents was less than 2 minutes.