Sorption of metals to clay minerals in the presence of complexing organic ligands

In recent years several models have been developed that have been used to predict the partitioning of a solute (metal or organic ligand) between water and a geological solid. These predictions are necessary for calculations of risk assessment associated with a deep underground nuclear waste repository. This thesis includes a review of international literature related to the reactions of metallic radionuclides with complexing organic ligands that may be present in and around a repository and the effect of these complexants on the sorption of radionuclides onto solids. The complexants include decontamination agents (EDTA, NTA and picolinic acid), degradation products of cellulose (ISA and gluconic acid), and humic and fulvic acids (HA and FA respectively) that may be present in the natural environment. The experimental work presented in this thesis uses a batch method to produce a comprehensive dataset of distribution ratios for the sorption of trace radioactive metals (Eu3+, Ni2+, Cd2+, Fe2+, and Cs+ in the presence, and absence, of organic complexants onto solid mineral phases (montmorillonite, kaolinite and goethite). [Continues.]