Diploma- & Master thesis

Studies on the influence of isosaccharic acid on the U(VI) retention of Ca-bentonite under alkaline conditions

Master student:
Paul Dullies
Prof. Vinzenz Brendler, Dr. Katja Schmeide
Surface processes
HTW Dresden

Short Description:

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.