Streaming Current and Streaming Potential Induced by Water Flow Through Porous Media

This study was conducted to investigate analytically and experimentally the relationship between the rate of flow of water through porous material and the streaming current and streaming potential induced by this flow. The effect of dissolved salts in the permeating solution and the size of the soil particles was also investigated. Results and conclusions of this study are summarized as follows: A modified procedure using the appropriate delay to insure stead state conditions was used for the measurements of both streaming current and streaming potential. The flow-pressure relationship was the same irrespective of the counter electro-osmosis (resulting from the streaming potential) and the change in salt concentration. Flows through the samples tested thus followed Darcy\u27s Law. The rate of flow (at a constant salt concentration and soil particle diameter) is directly proportional to the induced streaming current and streaming potential. Emperical equations in the form of I = C1q and E = C2q are suggested. A decrease in both streaming current and streaming potential was observed with increase of salt concentrate in the permeating solution. Comparable results were obtained for simulated natural waters and NaCl and KCl solutions, provided that the conductance of the solution was taken as a parameter. A decrease in current and potential was observed with increase of soil particle diameter. a Relationships of the form α = bN and β = C log N + d are suggested to express the effects of particle size and salt concentration on the streaming current and the streaming potential induced by the flow. Induced streaming potential was found to increase with the decrease in temperature. The analytical relationships developed together with the experimental work could probably be used as the basis of a method for measuring the rate of flow through porous material