Adsorptive removal of Uranium (VI) using zeolitic imidazole framework (ZIF)-67 from alkaline leach liquor

As the applications of nuclear technology diversify, development of adsorbents with superior selectivity and adsorption capacity for the removal of Uranium (U) from aqueous stream becomes imperative. In this article, zeolitic imidazolate framework-67 (ZIF-67) is used to examine the removal of U from simulated and actual alkaline leach liquor. The influence of pH and adsorbent dose were also analyzed. The synthesized ZIF-67 reveals a significant amount of U uptake capacity (396 mg g−1) and remarkable removal percentage for U in both synthetic and alkaline leach liquor (>98 % and 97.4 %, respectively). Based on various characterization techniques, a detailed U adsorption mechanism was established. The alkaline leach liquor was comprehensively characterized and different parameters (both before and after U adsorption) were determined. The ZIF-67 adsorbent showed satisfactory regeneration performance and structural integrity, with>80 % U removal after 5th regeneration cycle. For the purpose of forecasting the adsorption kinetics and related mass transfer parameters, a first principle based pore diffusion-adsorption model was used.