Efficient adsorption and in-situ ceramics immobilization of simulated trivalent actinides (Nd) by amino-functionalized mesoporous zirconia-silica

It is of great significance to develop a kind of adsorbent which can adsorb and in-situ immobilize radionuclides from aqueous solution. Herein, new amino-functionalized mesoporous zirconia-silica (ZNSi) composites were prepared and applied to adsorb and in-situ immobilize the simulated trivalent actinides (Nd) from aqueous solution. The obtained ZNSi composites exhibited high Nd adsorption capacity (31.14 mg/g) owing to the formation of Nd(OH)3 via the reaction between Nd3+ and OH− derived from the protonation of amino groups. The spent adsorbents with adsorbed Nd3+ were successfully changed to stable ZrSiO4-based glass ceramics by simple sintering treatment. The ZrO2 and Nd contents had great effect on the phase composition, microstructure evolution and aqueous stability of the obtained ZrSiO4-based glass ceramics waste forms. The immobilized Nd showed excellent aqueous stability (10−7 g m−2 d−1) due to the crystal lattice immobilization of ZrSiO4. Owing to the efficient adsorption and in-situ immobilization ability, the obtained ZNSi could be potential materials for radioactive wastewater treatment.