Glycerol-based deep eutectic solvents for efficient and reversible iodine uptake from vapour phase

The efficient capture and recovery of radioactive iodine (I₂) is crucial for nuclear safety and environmental protection. In this study, we propose some glycerol (Gly)-based deep eutectic solvents (DESs) as novel and promising solvents for iodine uptake from the vapour phase. Depending on the cholinium salt (Ch⁺) selected as hydrogen bond acceptor (iodide or chloride) and its relative ratio with respect to glycerol (1:2 or 1:3), the I₂ uptake approaches or even overcomes the 300 ms% with ChCl:Gly 1:2 showing the best performance with 4 g g^-1 after 24 h. Moreover, the captured I₂ can be effectively (almost 80%) released showcasing the potential of DESs as iodine sponges. Finally, the exploitation of Raman spectroscopy proves the speciation of I-based species within the DES, paving the way for further engineering of these systems. Our results highlight Gly-based DES as a sustainable and cheap solvent for effective and semi-reversible I₂ sponges.