We study removal of gas-phase organic methyl iodide (CH3I) from an ambient environment via adsorption onto organic additives, triethylenediamine (TEDA) and quinuclidine (QD), and transition metal impregnants. First principles density functional theory (DFT) calculations and ab-initio molecular dynamics (AIMD) simulations were extensively utilized to understand the underlying mechanism for the chemical reaction of CH3I. Our results suggest that the adsorption energy of CH3I shows substantial heterogeneity depending on the adsorption site, porosity of the AC, and humidity. It is observed that the CH3I dissociative chemisorption is largely influenced by the adsorption site. Organic additives show difference in adsorption performance with their basicity, and transition metals show different adsorption performance according to their bonding characteristics towards iodine. Most importantly, it is clearly shown that humidity plays a critical role in decreasing the adsorption efficiency, but for assisting the adsorption for QD. Our computational study can help to open new routes to design highly efficient materials for removing environmentally and biologically hazardous materials, for example radioactive iodine gas emitted following accidents at a nuclear power plant. We also propose innovative and insightful map to guide sorting out the best metal adsorbents and impregnants for dramatic improvement of the adsorptive removal of the radioactive iodine gas.
