Evidence for the existence of Tc(IV) – humic substance species by X-ray absorption near-edge spectroscopy
-
K. Geraedts
Summary
The redox–sensitive fission product technetium–99 has been investigated in systems containing different reducing solid phases (pyrite, magnetite, ironsulphide and Gorleben sand) on the one hand and Gorleben groundwater, which contains a high amount of humic substances, on the other hand. Initially, technetium–99 was added to these systems as pertechnetate (Tc(VII)), which was reduced in presence and absence of humic substances with the aid of the different reducing surfaces (neutral to alkaline pH). Both in absence and presence of humic substances, Tc concentrations were observed which exceeded the TcO2 solubility limit, whereby the presence of humic substances had a 100 fold higher Tc concentration compared to its absence. Using the La–precipitation method, it was shown that Tc(IV) inorganic colloids and organic colloids were quantitatively precipitated. It was demonstrated for the first time by a combination of chemical speciation methods (La–precipitation method and gel permeation chromatography) and XANES spectroscopy of the humic substance containing supernatant solutions, that Tc(IV) species were formed in these systems, indicating an association between Tc(IV) and humic substances.
© Oldenbourg Wissenschaftsverlag, München
Artikel in diesem Heft
- 239Pu and 241Am (n, 2n) cross-section measurements near En = 14 MeV
- Radiochemical studies relevant to the production of 86Y and 88Y at a small-sized cyclotron
- Berkelium redox speciation
- Solubility product of plutonium hydrous oxide and its ionic strength dependence
- Effective diffusivity of neptunium and plutonium in granite from Inada, Ibaraki, Japan under anaerobic conditions
- Theoretical predictions of hydrolysis and complex formation of group-4 elements Zr, Hf and Rf in HF and HCl solutions
- Evidence for the existence of Tc(IV) – humic substance species by X-ray absorption near-edge spectroscopy
- Measurement of L3 to M shell vacancy transfer probabilities of Th and U
- Radiochemical neutron activation analysis of trace impurities in high purity titanium and tungsten
- Thermochromatography of 241Am and 254Es in chlorinating carrier gases
Artikel in diesem Heft
- 239Pu and 241Am (n, 2n) cross-section measurements near En = 14 MeV
- Radiochemical studies relevant to the production of 86Y and 88Y at a small-sized cyclotron
- Berkelium redox speciation
- Solubility product of plutonium hydrous oxide and its ionic strength dependence
- Effective diffusivity of neptunium and plutonium in granite from Inada, Ibaraki, Japan under anaerobic conditions
- Theoretical predictions of hydrolysis and complex formation of group-4 elements Zr, Hf and Rf in HF and HCl solutions
- Evidence for the existence of Tc(IV) – humic substance species by X-ray absorption near-edge spectroscopy
- Measurement of L3 to M shell vacancy transfer probabilities of Th and U
- Radiochemical neutron activation analysis of trace impurities in high purity titanium and tungsten
- Thermochromatography of 241Am and 254Es in chlorinating carrier gases
