Hydrated titanium dioxide modified with potassium cobalt hexacyanoferrate(II) for sorption of cationic and anionic complexes of uranium(VI)

Abstract

Hydrated titanium dioxide was modified with K2Co[Fe(CN)6] nanoparticles with size up to 10 nm. The nanoparticles are unaggregated, since they are stabilized by the inorganic matrix. The optimal modifier content, which allows us to obtain large granules of the composite, was found. The modifier nanoparticles loose titanium dioxide increasing its micro- and mesoporosity. Sorption of both cationic and anionic forms of U(VI) under batch conditions was investigated. The modifier improves sorption from one- and multicomponent solutions, especially in weakly acidic and neutral media: the removal degree of U(VI) reaches 80–100%. When the concentration of U(VI) is 0.02–0.04 mmol dm−3, the modifier increases the degree of U(VI) removal from river water by 50%. Sorption rate is described by the model of pseudo-second-order. The modifier slows down sorption of cations, while no effect on the rate of anion sorption has been found. Sorption isotherms are described with Freundlich model. The K2Co[Fe(CN)6] nanoparticles decrease energetic heterogeneity of sorption centers.