Uranium sorption onto opalinus clay and uranium complexation with model ligands - New results.

An anaerobic opalinus clay sample was characterized (BET, TC, TOC, CEC, XRD, IR). No significant differences between the aerobic and the anaerobic clay could be determined.
The uranium(VI) sorption onto aerobic opalinus clay (S/L = 60 g/l) in opalinus clay pore water in absence and presence of humic acid was investigated and compared with the according uranium(VI)-kaolinite sorption results.
The model ligands mandelic acid and glycolic acid were chosen for the uranium(IV) complexation. The complex formation constants for the uranium(IV) complexation were determined applying UV-Vis absorption spectroscopy. Thereby, the hydrogen ion concentration was varied.
Sulfur-containing humic acid model substances were synthesized and characterized (S-content, PEC, FTIR, XPS). First investigations of the uranium(VI) complexation of humic acid type M1-S1 were performed.