Fabrication of amino-functionalized Ce/Mn bimetallic organic framework and its efficient performance on Uranium(VI) extraction in aqueous solutions

Abstract

Uranium (U(VI)) removal from nuclear-contaminated water is still an obstacle that needs to be solved quickly. Herein, looking for efficient, fast, and highly selective separation of U(VI) versatile material is of great significance. In this study, a novel Ce/Mn bimetallic modified aminated MOF material UiO-66-NH2 was synthesized through solvothermal reaction by using ZrOCl2·8H2O as a sacrificial template, which was employed as an adsorbent in radioactive remediation. The characterization of the adsorbent Ce/Mn-UiO-66-NH2 was investigated by XRD, FTIR, SEM, and BET and the results indicated that Zr in UiO-66-NH2 had been partially replaced by Ce/Mn successfully. Through batch adsorption experiments, we found that the maximal capture capacity of the produced adsorbent for U(VI) was 1218.78 mg/g at 313 K, and the elimination process fitted well with pseudo-second-order kinetic model and the Langmuir isotherm model. The thermodynamic parameters indicate that the adsorption process of U(VI) was endothermic and spontaneous which was regulated by chemisorption. After 5 times recycling, the removal rate still exceeded 83.5 %, indicating that Ce/Mn-UiO-66-NH2 was a promising adsorbent that can effectively remove U(VI) in radioactive wastewater. The increased adsorption capacity was proposed attributed to complexation and electrostatic attraction between the radionuclides and the introducing functional groups as well as Ce or Mn ions. This study provides a reference value for radioactive wastewater remediation.