A Laboratory Study of Electromigration as a Possible Field Technique for the Removal of Contaminants from Ground Water

Abstract

AbstractA method for removing dissolved contaminants from ground water by emplacing electrodes in the aquifer has been tested using laboratory columns of pure quartz silty sand saturated with solutions of CuSO4 and copper‐contaminated synthetic ground water. In the Soviet Union a similar method is commonly used in searching for hidden deposits of metallic minerals. In the Soviet method, electrodes are emplaced in the ground and ions of the metals being sought are caused to migrate along an imposed voltage gradient; the ions are collected for analysis in acid‐filled ceramic cylinders which surround the cathodes.In this study, quick‐freezing was used to obtain the distribution of ions within the columns as a function of time and space. With voltages up to 2.5 V and cur‐rents of a few tens of microamps, more than 50 percent of the dissolved copper was removed from the interstitial fluid in the porous columns in a period of five days. Current efficiencies ranged from more than 80 percent to less than 5 percent, depending on such factors as length of time of electrolysis, pH, concentration of Cu, and presence of other ions. The efficiency and economics of the technique of electromigration should be evaluated in additional laboratory studies and in the field, but in theory the method should be useful for removing any charged species in ground water, including some organics.