Electrochemistry of technetium analogues rhenium and molybdenum in room temperature ionic liquid

Rhenium was used as an analog for Technetium to study the electrochemical redox properties because the two elements share the same stable oxidation states in aqueous solutions. However, Tc-99 is radioactive and is not readily available for experimentation purposes. Molybdenum is also of interest because when Mo-99 is irradiated, the decay products are Tc-99m and Tc-99. Approximately 30% Tc-99m is eluted from the Mo columns for radiopharmaceutical use with the remaining Mo-99 source decaying to Tc-99 which is discarded as radioactive hospital waste. Currently there are no viable procedures for the reclamation of the radioactive Tc-99 from either fission streams or from the hospital waste. Investigating the electrochemical properties of Re and Mo are important for developing methodologies to increase the percent elution of Tc-99m, and ultimately improve reclamation procedures of the waste Tc-99. In this study RTIL solutions are utilized in place of aqueous solutions for the electrochemical analysis and deposition of both Re and Mo. In these studies the RTIL was used to eliminate the competitive side reactions associated with water, remove the acid dependence associated with the reduction of Re and Mo species, and extend the negative potential window such that reduction of the species to metal was achieved. The electrochemical and SEM results indicate that Re and Mo were reduced and deposited onto working electrodes. With the growing stores of hazardous technetium from the medical industry and nuclear fuel reprocessing, mechanisms for deposition and recovery are increasingly important. The studies outlined in this thesis defense increase our understanding of the electrochemistry of stable analogues, Re and Mo and in turn increase our understanding suggesting that the target recovery of Tc can be achieved using RTIL solutions.