Effective removal of uranium from aqueous solution by using novel sustainable porous Al2O3 materials derived from different precursors of aluminum

Abstract

Three kinds of porous Al₂O₃ materials have been prepared by using different precursors of aluminum via solution-freeze-drying-calcination technology. Meanwhile, the adsorption properties of Al₂O₃-Cl, Al₂O₃-N and Al₂O₃-S adsorbents to U(VI) were estimated and compared. The calculated maximum adsorption amount of porous Al₂O₃ materials at 298 K reached 805.72 mg g⁻¹ for U(VI) (pH = 7.0), which was much higher than that of most of the other metal oxides. Moreover, it is worth mentioning that the remarkable adsorption efficiency was above 90% even after five cycles and the adsorption efficiency was relatively high in the solution with different coexisting ions. Crucially, U(VI) was almost adsorbed completely on Al₂O₃-Cl at the low concentration and only about 0.006 mg L⁻¹ remained in the solution, which was below the permissible limits of the USEPA (0.03 mg L⁻¹) and WHO (0.015 mg L⁻¹). Based on the above results, it could be demonstrated that the novel porous Al₂O₃ materials had broad application prospects for U(VI) removal.