Electrolytic reduction of Re(VII) using a flow type electrolysis cell and its possibility of radiopharmaceuticals application

he electrochemical properties of perrhenate were studied in hydrochloric acid solution via cyclic voltammetry by disk glassy carbon electrode. The electroreduction of perrhenate was performed at a constant potential -0.33 V (vs. Ag/AgCl) with a potentiostat by a flow type electrolysis cell. It was found that the change of rhenium ion concentration before and after electrolysis was negligible. This means almost no rhenium or rhenium oxides were deposited on the carbon fiber electrode during the electroreduction. The rhenium ion solution changed from colorless into yellow-brown after electrolysis process. UV-Visible spectrophotometry was used to characterize the oxidation states of Re before and after electrolysis. Some obvious peaks were detected after electrolysis, indicating that Re(VII) was reduced to Re(V). The complex behavior and stability of Re(V)-HEDP were discussed for the purpose of electroreduction of Re(VII) or Tc(VII) on radiopharmaceuticals production.