Diethylenetriamine tethered mesoporous silica for the sequestration of uranium from aqueous solution and seawater

Mesoporous silica (MCM-41) with large surface area and porosity has been synthesized and tethered covalently with the uranium (VI) specific ligand, namely diethylenetriamine (DETA) on MCM-41. The adsorbent, abbreviated as MCM-DETA, was characterized by BET surface area, BJH pore size and particle size distribution, thermogravimetry, SEM-EDX analysis, and FT-IR spectroscopy, and studied for the adsorption of uranium from aqueous solution. The parameters evaluated were the effect of pH of the aqueous phase, duration of equilibration, concentration of uranium in the aqueous phase, and the effect of interfering ions on the adsorption of uranium (VI) on MCM-DETA. The adsorption behavior of uranium from seawater (U(VI) = 10 mg.L-1) was studied by batch equilibration method. The results revealed that MCM-DETA showed rapid adsorption kinetics (k2 = 2.85 × 10-3 mol.L-1. min-1), extremely large Langmuir adsorption capacity (1067 mg.g-1), good selectivity over other interfering ions, and efficient adsorption of uranium from seawater (680 mg.g-1) spiked with uranium, indicating that MCM-DETA a promising candidate for the adsorption of uranium from aqueous solution and seawater.