Impact of Conformational Isomerism in Two Zn-MOFs on the Multimedia Incarceration of Iodine: In-Depth Experimental and Computational Assessments

Owing to the accelerating demand for energy production using nuclear power, the risk has risen of radionuclide outbreak, which caused several irreparable damages in the past. Thus, various porous materials have been utilized to showcase iodine capture in different media. In this work, two Zn-based metal organic frameworks (MOFs) that are conformational isomers, {[Zn(bpaipa)]·DMF·2H2O}n (1) and {[Zn(bpaipa)]·5H2O}n (2), with varying polarizing tendencies were utilized for incarcerating iodine molecules at high uptake values from different iodine reservoirs, i.e., at elevated temperatures, and aqueous and organic media. At elevated temperatures (e.g., 75 °C), quite a large amount of iodine vapors transferred to 1 and 2 (2.95 g g–1 and 4.51 g g–1, respectively). Being stable in an aqueous medium, both MOFs performed well by transferring 2.38 (±0.049) g g–1 (by 1) and 2.9 (±0.015) g g–1 (by 2) of I3– from the ionic iodine reservoir. In addition to this, a real-time matrix was also taken for an aqueous iodine reservoir in which the materials worked remarkably. The organic phase iodine transfer has also been studied by both MOFs. For all the cases, a systematic kinetic study has been conducted. The results show that their structural distinctiveness plays a crucial role in the unprecedented comparative study of mass transfer from all three iodine reservoirs. On account of the sorbent's polarizing capacity, a detailed explanation is provided using thermogravimetric analysis, Raman, and X-ray photoelectron spectroscopy. Insights into the interactive modes between iodine (in both neutral and ionic forms) and 1 and 2 are critically evaluated using configurational bias Monte Carlo simulations. Furthermore, 1 and 2 are found to be reversible in iodine capture and release as well as recyclable and stable under the experimental conditions. For a very high uptake in the vapor phase and its room-temperature synthesis, 2 is an exceptional candidate for efficient and reusable sequestering of iodine in long-term and real-time situations.