Diploma- & Master thesis
Studies on the influence of isosaccharic acid on the U(VI) retention of Ca-bentonite under alkaline conditions
In repositories for low and intermediate level nuclear waste, cellulose degrades due to the highly alkaline conditions caused by cement degradation within the repository. This leads to water-soluble organic compounds like ISA, a polyhydroxo-carboxylic acid, which can be problematic in terms of forming strong soluble complexes with Uranium. In other words, ISA could lower the sorption of U(VI) on clay-minerals used for the construction of the repository and increases its mobility.
Based on research for the binary systems U(VI)-bentonite (GRaZ-project) and U(VI)-isosaccharinic acid (MIND-project), this thesis takes a closer look on the ternary system U(VI)-bentonite-ISA. The main focus lies on the influence of ISA on the sorption of U(VI) on Ca-bentonite under repository conditions (pH 8-13, anaerobe). Therefore especially batch-sorption-experiments will be carried out to determine under which conditions the presence of ISA exhibits an effect on U(VI) sorption. Furthermore U(VI)- ISA-complexes should be identified via spectroscopic methods (TRLFS, UV-vis), to draw conclusions about their impact on U(VI) retention processes.