Efficient capture of radioiodine from aqueous solutions is of importance for sustainable development of nuclear energy and protection of the environment. However, current adsorbents under exploration suffer from limited adsorption capacity and powder form that are unfavorable for practical applications. Herein, we applied a "multi-functionalization integration" idea to construct novel electrospun fiber adsorbents (N-MOF-PAN fibers) containing cationic quaternary ammonium groups, uncharged amine groups, and porous MOF material (UiO-66-NH2), which in synergy adsorb iodine effectively from both saturated I2 aqueous solution and I3- aqueous solution. Iodine species (94.6%) could be removed from saturated I2 solution within 180 min, and 98.7% of iodine species were captured from I3- solution within 240 min. Additionally, the N-MOF-PAN fibers exhibited high iodine uptake capacities of 3.56 g g-1 from a concentrated KI/I2 aqueous solution and 3.61 g g-1 from the Langmuir isotherm model, surpassing many reported iodine adsorbents in the aqueous medium. Characterization and mechanism analysis indicated that multiple active sites simultaneously attribute to the high binding affinity toward iodine species through physical adsorption and chemical adsorption. Furthermore, benefiting from their macroscopic architecture, N-MOF-PAN fibers were used as the adsorption column for dynamic iodine capture with a bed volume of 1490 mL, which is much higher than commercially activated carbons. Overall, this work provides guidance for the development of novel fiber adsorbents for related applications.
Keywords: N-containing functional groups; UiO-66-NH2; electrospinning; fiber adsorbents; iodine capture.