ELECTROCHEMICAL BEHAVIOUR OF PERTECHNETATE AT THE RING DISK ROTATING ELECTRODE
The electrochemical behaviour of aqueous pertechnetate solutions has been extensively studied on a wide pH range. The conclusions drawn by various authors are rather different, but there is an almost general agreement that in neutral solutions a potential below -500 mV is required for the reduction of pertechnetate, i.e. a potential similar to that observed under basic conditions. Utilizing a ring disk rotating electrode, reduction of pertechnetate in neutral solutions occurs at approximately +70 mV. Considering the reaction leading to tetravalent technetium: TcO-4**- + 4 H**+ + 3 e**- = TcO(OH)-2 + H-2O it can be seen that 4 hydrogen ions are consumed in the reduction of 1 mole of pertechnetate. Therefore, previous values obtained with stationary or dropping electrodes could have been measured under basic conditions, due to alkalinization of the solution in proximity of the electrode. In conclusion, it has been shown that moderate reducing conditions, such as those occurring in anoxic soils and sediments, should be sufficient to transform the anion pertechnetate, very mobile in the environment, into chemical species of technetium at a lower valence state, which can be easily immobilized.
Bibliographic Reference: 2ND INTERNATIONAL SYMPOSIUM ON TECHNETIUM IN CHEMISTRY AND NUCLEAR MEDICINE, PADOVA (ITALY), SEPT. 9-11, 1985 AND JOURNAL OF NUCLEAR MEDICINE AND ALLIED SCIENCES, VOL. 29 (1985), NO. 3, PP. 211-212
Record Number: 1989124015300 / Last updated on: 1987-01-01
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