A Cationic Silver -MOF with Colorimetric Feedback for Efficient Removal of Permanganate from Wastewater

The extraction of hazardous oxoanions, including the carcinogenic permanganate (MnO₄⁻), from industrial effluents presents a significant challenge due to their persistence in the environment and associated health risks. In this study, we introduce a three-dimensional, water-stable cationic silver-organic framework (Ag-MOF) specifically engineered for the effective sequestration of MnO₄⁻. This framework is composed of Ag(I) nodes and a sulfur-based thioimidazole ligand, showcasing a novel architecture that incorporates charge-balancing tetrafluoroborate (BF₄⁻) anions within its porous channels. These BF₄⁻ ions serve as exchangeable reservoirs, enhancing the framework's ability to rapidly capture MnO₄⁻ through structural and electrostatic compatibility. Importantly, the adsorption process is marked by a noticeable chromogenic transition (from purple to colorless), allowing for immediate visual verification of MnO₄⁻ removal. The Ag-MOF demonstrates outstanding efficacy, achieving over ۹۹% removal of MnO₄⁻ from concentrated solutions (۱۰۰۰ ppm) at equilibrium, without any structural degradation in aqueous environments. This dual capability, high-capacity oxoanion capture combined with self-indicating properties, arises from the meticulous alignment of host-guest interactions and the framework's durable coordination network. By merging anion exchange, stability, and sensory feedback within a single material, this research propels the advancement of multifunctional metal-organic frameworks (MOFs) aimed at tackling priority pollutants as identified by the U.S. EPA. This highlights their promise in the evolution of next-generation water treatment technologies.

کلیدواژه ها:

MnO ۴- removal ، Adsorption ، Silver -MOF