Dual-function Ag2O/Zn-hemin MOF composites for radioactive iodide: performance and mechanism studies for removal and efficient visual detection.

The development of integrated strategies for monitoring and managing radioactive iodine in wastewater is of critical urgency. However, no existing material can simultaneously detect and remove I- from aquatic environments. Here, a novel Ag2O/Zn-hemin MOF nanocomposite was developed, integrating dual functionality for both trace-level colorimetric detection and high-capacity removal of I-. A smartphone-assisted I- colorimetric sensor was developed for the first time based on the inhibitory effect of I- on the peroxidase-like activity of Ag2O/Zn-hemin MOF. Research findings indicate that I- can adsorb onto the surface of the Ag2O/Zn-hemin MOF. This ultimately leads to the suppression of POD-like activity. The sensor delivers excellent performance, including a wide detection range (0.10 μg L-1 to 800 μg L-1), an ultra-low detection limit (0.06 μg L-1), and good selectivity. The sensor performance was validated through DFT calculations. As an adsorbent, Ag2O/Zn-hemin MOF exhibits fast equilibrium kinetics (≤10 min) and high removal efficiency (adsorption rate 95 %). This work has achieved the efficient removal and trace detection of I- for the first time, providing a new approach to the treatment and monitoring of I- pollution in complex systems.