Electrosorption and reduction of pertechnetate by anodically polarized magnetite

The radionuclide technetium is a common surface and groundwater contaminant at many nuclear fuels processing facilities. This research investigated a new method for removing pertechnetate from contaminated waters based on the low aqueous solubility of reduced technetium species. The removal method i nvolved electrostatic adsorption of pertechnetate at an anodically polarize d magnetite electrode, followed by reduction of the adsorbed Tc(VII). This method was capable of reducing technetium associated beta activity below th e 900 pCi/L drinking water maximum contaminant level set by the US EPA for manmade beta activity. Upon termination of the applied polarization, the re duced technetium species remained adhered to the magnetite electrode under anaerobic conditions. Under aerobic conditions, the technetium was slowly r eleased back into solution, indicating that the reduced technetium is affor ded a degree of cathodic protection due to preferential oxidation of the ma gnetite. The advantages of this electrosorption/reduction technique over di rect cathodic reduction are an increase in the stability of the reduced tec hnetium, removal to lower aqueous concentrations, and greatly increased rem oval kinetics.