High performance of phosphonate-functionalized mesoporous silica for U(vi) sorption from aqueous solution

TLDR

The growing interest in nuclear energy has spurred research into separating and enriching radionuclides from nuclear fuel. This study develops phosphonate‑functionalized mesoporous silica (NP10) as a sorbent for U(VI) removal from water. NP10 was synthesized by co‑condensation of DPTS and TEOS in the presence of CTAB, yielding mesoporous silica capable of preconcentrating U(VI) from aqueous solutions. NP10 achieved a maximum U(VI) capacity of 303 mg g⁻¹, equilibrated within 30 min at neutral pH, allowed easy desorption with 0.1 M HNO₃ enabling reuse without loss of capacity, and achieved a preconcentration factor of 100.

Abstract

The renaissance of nuclear energy promotes increasing basic research on the separation and enrichment of nuclear fuel associated radionuclides. Herein, we report the first study for developing mesoporous silica functionalized with phosphonate (NP10) as a sorbent for U(VI) sorption from aqueous solution. The mesoporous silica was synthesized by co-condensation of diethylphosphatoethyltriethoxysilane (DPTS) and tetraethoxysilane (TEOS), using cationic surfactant cetyltrimethylammonium bromide (CTAB) as the template. The synthesized silica nanoparticles were observed to possess a mesoporous structure with a uniform pore diameter of 2.7 nm, and to have good stability and high efficiency for U(VI) sorption from aqueous solution. A maximum sorption capacity of 303 mg g−1 and fast equilibrium time of 30 min were achieved under near neutral conditions at room temperature. The adsorbed U(VI) can be easily desorbed by using 0.1 mol L−1HNO3, and the reclaimed mesoporous silica can be reused with no decrease of sorption capacity. In addition, the preconcentration of U(VI) from a 100 mL aqueous solution using the functionalized mesoporous silica was also studied. The preconcentration factor was found to be as high as 100, suggesting the vast opportunities of this kind of mesoporous silica for the solid-phase extraction and enrichment of U(VI).