This study aimed to develop effective adsorbents for capturing radioactive iodine in nuclear power waste gas. Two zinc metal−organic frameworks (Zn-MOFs) were synthesized and found to have favorable properties such as a large surface area, thermal stability, surface rich in π-electron-containing nitrogen, and redox potential. Adsorption experiments revealed maximum capacities of 1.25 and 1.96 g g −1 for the MOFs at 75 °C, with the pseudo-second-order kinetic model fitting the data well. The Langmuir equation provided a better fit in cyclohexane, with maximum adsorption amounts of 249 and 358 mg g −1 for Zn-MOF-1 and Zn-MOF-2, respectively. The MOFs were also stable during six cycles of adsorption and desorption. Furthermore, electron transfer occurred due to the synergistic adsorption of Zn, N, and O atoms, resulting in the conversion of some iodine to polyiodide. Zn-MOF-2 exhibited better chemisorption than Zn-MOF-1 due to a smaller highest occupied molecular orbital (HOMO)−lowest unoccupied molecular orbital (LUMO) gap. Notably, it was discovered that N-containing radicals had stronger interactions with iodine compared to radicals without N. These findings provide valuable insights into MOF synthesis and environmental protection.
Metal-organic frameworks (MOFs) have great potential for the capture of
volatile iodine. The effect of a precise regulation of active sites in
JLNU-4 (MOFs) on capture of iodine was investigated by Monte Carlo (MC)
method and molecular dynamics (MD), and it was found that the larger the
Zn/Cd atomic ratio, the better the iodine capture. Interestingly,
compared with the meta-position regulation of Zn/Cd, the ortho-positions
regulation increased the free volume of the crystal and enhanced the
interaction between Cd and I, thus improving the capture capacity of
iodine. The first-principles study revealed the charge transfer of each
atom in the MOFs crystal with I2 during iodine capture and the secondary
bonds with weak covalent interactions were all formed after I2
adsorption onto MOFs. These findings provide a reference for the capture
of radioactive iodine and a theoretical basis for the strategies for
precise regulation of MOFs in the future.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.