Capillary method and molecular dynamics study of the diffusion and molecular structures of vanadium(IV)-ligand complexes

To better understand the diffusion behaviors of Tc(IV)-L complexes in the water-rock system, the diffusion coefficients (Dw) of VO2+ [as a surrogate to 99Tc(IV)] and their complexes with ligands (Oxalate, NTA and EDTA) in water were studied by a capillary method. The density functional theory was employed to investigate the complexation between VO2+ and ligands. The Dw values of [VO(Ox)2]2−, [VO(NTA)]− and [VO(EDTA)]2− were 18–26% higher than that of VO2+ due to the smaller molecular radii of the complexes.