Investigation of the Eu(III)-B(OH)3-Organic System

Borates and organic matter (humic and fulvic acids, small organic molecules) are ubiquitous compounds in the environment (rocks, soils, natural waters).
Concerning the safety and risk assessment for a nuclear waste repository the interaction between trivalent lanthanides and actinides and borates is interesting to study. Borates occur in salt deposits (possible host rock for nuclear waste repositories) and can be release due to corrosion of vitrified waste block (borosilicate glass) and storage containers.
The investigations concentrate on the reaction between Eu(III) and borates in aqueous solution.
For boric acid (B(OH)3) no and for polyborates weak complexation properties concerning Eu(III) are observed.
The complexation between Eu(III) and salicylate is influenced by boric acid due to the formation of a borate ester.
Furthermore at pH 6 the formation of a solid Eu borate species in presence of polyborates is observed. The formation of the solid Eu borate species depends on the polyborate concentration and ionic strength.