SORPTION REMOVAL OF Sr2+ AND Y3+ IONS FROM AQUEOUS SOLUTIONS BY A TiO2 -BASED SORBENT

In present investigations, the sorption removal of Sr2+ and Y3+ ions from aqueous solutions by TiO2 – La sorbent was researched. The dependence of the sorption process on the time of interaction, solution’s acidity, and initial concentrations of the Sr2+ and Y3+ ions were investigated. Four simplified kinetic models – Lagergren’s pseudofirst and pseudo-second order kinetic models, Intra-particle diffusion and Elovich models – were tested to describe the adsorption process. Equilibrium isotherms data were analyzed using Langmuir and Freundlich isotherm models. The kinetic data indicated that the adsorption of Sr2+ and Y3+ ions by ТіО2–La fitted well with the pseudo-second order kinetic model with coefficients of linear approximation (R2 = 0.99) for both elements. The application of the Elovich model to the experimental data of the sorption of Sr2+ and Y3+ ions by ТіО2–La shows that yttrium is absorbed due to the mechanism of chemisorption. Coefficient of linear approximation R2 = 0.98. Strontium is absorbed via physical sorption or ion exchange mechanism. The maximum adsorption capacity of ТіО2 –La was found to be 0,9 mmol·g-1 (79 mg g-1) for Sr2+ and 1.6 mmol·g-1 (134 mg·g-1) for Y3+.