A Water-Stable Cationic Metal–Organic Framework with Hydrophobic Pore Surfaces as an Efficient Scavenger of Oxo-Anion Pollutants from Water

Water contamination due to heavy metal-based toxic oxo-anions (such as CrO42– and TcO4–) is a critical environmental concern that demands immediate mitigation. Herein, we present an effort to counter this issue by a novel chemically stable cationic metal–organic framework (iMOF-2C) with strategic utilization of a ligand with hydrophobic core, known to facilitate such oxo-anion capture process. Moreover, the compound exhibited very fast sieving kinetics for such oxo-anions and a very high uptake capacity for CrO42– (476.3 mg g–1) and ReO4– (691 mg g–1), while the latter being employed as a surrogate analogue for radioactive TcO4– anions. Notably, the compound showed excellent selectivity even in the presence of other competing anions such as NO3–, Cl–, SO42–, ClO4–. etc.. Furthermore, the compound possesses excellent reusability (up to 10 cycles) and is also employed to a stationary phase ion column to decontaminate the aforementioned oxo-anions from water.