Improvement of U(VI) removal by tuning magnetic metal organic frameworks with amine ligands

A magnetic metal organic framework was finely tuned by abundant amine groups (Mag MOF-NH2) for the purpose of improving the U(VI) removal from solution. The Mag MOF-NH2 displays outstanding removal capacity (80 mg⋅g−1) to U(VI) (10 ppm, 400 mL) within 15 min. To illuminate the adsorption mechanism of Mag MOF-NH2, the microstructure, the magnetic property, chemical composition of Mag MOF-NH2 and the reaction system were characterized. The adsorption mechanism was systematically investigated. Equilibrium adsorption experiments verifies the improved adsorption capability from nearly 0 for MIL-101 to 82 mg⋅g−1 for Mag MOF-NH2, which could be explained mainly by the interaction between the amine groups and targeted ions. The effect of humic acid (HA) and coexisting ions on the U(VI) adsorption were also investigated. The Ca2+ and Mg2+ ions have passive impact on the adsorption and the high pH value can facilitate the process. Mag MOF-NH2 holds great potential for the practical application owing to the outstanding U(VI) removal and satisfied regeneration in simulative wastewaters.