Performance and mechanism for U(VI) adsorption in aqueous solutions with amino-modified UiO-66

The adsorption performance and mechanism of the amino-modified zirconium-based metal organic framework (UiO-66-NH2) for the removal of U(VI) in aqueous solution were studied. Compared with UiO-66, UiO-66-NH2 shows better adsorption performance due to the introduction of amino groups. The adsorption characteristics of factors such as pH, UiO-66-NH2 dosage and contact time were investigated. The results show that the maximum adsorption capacity is 384.6 mg g−1 at pH = 6 and T = 313 K. The adsorption conforms to the quasi-second-order kinetic model and the Langmuir isotherm model. The thermodynamic parameters indicate that the adsorption process of U(VI) is endothermic and spontaneous. After five cycles, the removal rate of U(VI) still exceeded 83.53%. The results indicate that UiO-66-NH2 is a promising adsorbent that can effectively remove U(VI) in radioactive wastewater.