Sorption of europium onto diethylenetriaminepentaacetic acid based silica dioxide. Kinetics, isotherm, thermodynamics

As a long-lived radionuclide, americium (Am) in spent nuclear fuel is a tricky isotope that partially impedes nuclear waste reclamation. This study dealt with sorption of europium (Eu) as a nonradioactive surrogate for Am onto diethylenetriaminepentaacetic acid based SiO₂ (DTPA-SiO₂). Equilibrium isotherms, kinetics, thermodynamics and pH experiments were investigated batch wise. The sorption strongly depended on pH. The maximal europium sorption capacity reached 192.42 mg/g, much higher than any currently reported. Thermodynamic parameters suggested the sorption was a spontaneous, exothermic and entropy increase process. Regeneration results showed the acceptable loss in the sorption ability after five circulations, indicating good reusability. (author)