Kinetics of Exchange of Cs+, Co2+ and Sr2+ on Synthetic Hydrous Titanium Oxides

Abstract

In the present work, a study of the kinetics of adsorption of Cs+, Co2+, and Sr2+ on four hydrous titanium oxides, prepared in different media, and designated as Ti‐I, Ti‐II, Ti‐III, and Ti‐IV, was carried out. In the aqueous medium, the internal diffusion coefficients, Di for Cs+ were found to be equal to 3.7×10−9, 3.7×10−9, 2.3×10−9, and 1.5−10−9 cm2/s, in Ti‐I, Ti‐II, Ti‐III, and Ti‐IV, respectively. For Co2+ and Sr2+, these values are equal to 0.96×10−9 and 0.64×10−9 cm2/s, respectively for Ti‐IV. In Ti‐IV, Di for all ions generally increases on adding methanol or propanol. This is probably due to greater dehydration, leading to faster ion diffusion, and, hence, to a decrease of ion mobility due to stronger interaction with the surface. In all media in Ti‐IV, the order: Di(Cs+)>Di(Co2+)≥Di(Sr2+) was found which is due to a stronger interaction of the bivalent ions with the exchange sites.