A Zr/Ti-based bimetallic AO-UiO-66 framework for effective uptake of radioactive iodine

Abstract

To develop porous solid-state materials for the effective capture of radioactive iodine in both vapor and solution phases is of great importance. In this work, a Zr/Ti-based bimetallic metal–organic framework (AO-UiO-66-ZrTi11) was synthesized via a simple solvothermal method using 2,5-bis(allyloxy)terephthalic acid, ZrCl₄ and Cp₂TiCl₂. This MOF solid was fully characterized and extensively evaluated for its I₂ capturing performance. AO-UiO-66-ZrTi11 demonstrated significantly enhanced I₂ uptake capacity, achieving as high as 2.46 g g⁻¹ for iodine vapor and 1084.4 mg g⁻¹ for iodine/cyclohexane solution. Kinetic studies of iodine adsorption from solution revealed rapid kinetics, with the process fitting well to the pseudo-second order kinetic model. The superior adsorption performance of AO-UiO-66-ZrTi11 for iodine can be attributed to its unique bimetallic structural features and functional groups. This work provides valuable insights for the further development of efficient adsorbents towards capturing radioactive iodine.