Highly efficient triiodide ion adsorption from water by ionic liquid hybrid metal–organic frameworks

The development and utilization of nuclear energy is one of the effective ways to reduce carbon emissions and achieve the goal of global carbon neutrality. However, it is inevitable to release radioactive pollutants, such as I3−, into the environment during the utilization of nuclear energy, and the efficient adsorption and storage of iodide ion remains a challenge. In this work, a series of ionic liquid (IL) hybrid metal–organic framework (MOF) materials have been developed by simple impregnation of hydrophobic ILs into nanopores of stable MOFs for high-efficient I3− absorption from water for the first time. It is found that the hybrid materal [C2mim][Tf2N]@UiO-67–30 % exhibits a record high I3− absorption capacity at room temperature (4.30 g·g−1), and the I3− absorption capacity of [C2mim][Tf2N] in UiO-67–5 % is 10 times that of the neat [C2mim][Tf2N]. The adsorption process can be well described by Freundlich model and pseudo-second-order model. Such superior I3− absorption capacity is mainly attributed to the multiple sites interaction between anion of the highly dispersed IL and I3−, although cation of the IL and benzene ring of MOF framework also have contribution for the adsorption.