Exploring MIL-101 (Cr) and Its Polymeric Composites as Potential Adsorbents for Volatile Iodine from Nuclear Off-gas: A Detailed Experimental and Computational Study

Owing to the rapid growth of nuclear energy as a sustainable, affordable, and clean energy source, the entrapment of radioactive iodine released from the nuclear off-gas stream is considered a vital concern. We view MOFs as potential futuristic adsorbents for this remedy. Herein, we examined the gravimetric iodine adsorption characteristics of radiation and chemically stable MIL-101(Cr) and its polymeric composites with variation of temperatures. The saturation adsorption capacity shown by pristine MIL-101(Cr) is 4.1 g I2 g–1, and the saturation capacity of composites varies based on MIL-101(Cr)’s concentrations. MIL-101(Cr)@PES 2:1 shows an uptake capacity of 2.1 g I2 /gbead, which is ∼ 350% superior to the reported HKUST-1@PES and ∼150% higher compared to [email protected]. Based on various spectroscopic studies and DFT calculations, probable host–guest interactions leading to enhanced I2 adsorption have been elucidated. The open Cr metal site acts as the initial adsorption site for I2 that gets converted into iodide and afterward to higher polyiodide through the transfer of charge from the host matrix. These findings suggest that MIL-101(Cr) can be considered one of the potential alternate adsorbents for radioactive iodine.