Adsorption of yttrium by the sodium-modified titanium dioxide: Kinetic, equilibrium studies and investigation of Na-TiO2 radiation resistance

The adsorption of yttrium cations from an aqueous solution of YCl3 by sodium-modified titanium dioxide (Na-TiO2) was investigated. The Na-TiO2 was obtained by impregnating Na+ cations into the surface layer of TiO2 nanoparticles. The synthesis of nanoparticle TiO2 was performed by a liquid-phase sol-gel method, using the aqua complex of [Ti(OH2)6]3+‧3Cl- as a precursor. Nanoheterostructured Na-TiO2 is an anatase modification of TiO2. The amount of incorporated sodium cations on the TiO2 surface is about 6%. The surface area of Na-TiO2 is 239 m2‧g-1; the volume of mesopores is 0.098 cm3‧g-1; that of micropores is 0.054 cm3‧g-1. Yttrium ion adsorption was investigated under batch conditions. Complexometric titration and mas-spectrometric analysis determined the initial and equilibrium concentration of yttrium. The radiation resistance of Na-TiO2 to the influence of beta irradiation was investigated as well. For this purpose, the radiation of β--particles of the 90Sr-90Y source "Sirius" was used. The flux of β- - particles was 2.1‧108 electrons/sm2‧s; the maximal energy of incident electrons was 2.28 MeV. It was shown that the investigated adsorbent has a high adsorption capacity toward yttrium cations. The maximum adsorption is about 259 mg/g. The adsorption kinetic is fit well with the kinetic model based on the pseudo-second-order equation. The equilibrium adsorption of yttrium cations is described by Freundlich's theory with high reliability. The adsorbent is resistant to the influence of β- - irradiation. This is manifested in the invariance of its adsorption capacity toward yttrium cations after irradiation. Na-TiO2 is a promising material for the adsorption of yttrium and Rare Earth elements and can be used as the basis for the 90Y isotopic generator.