Nitrogen-functionalized Zeolites for Enhanced Cobalt Decontamination

Efficient removal of radioactive cobalt ions is essential for ensuring the safety of nuclear power operations. Although natural or synthetic zeolites exhibit moderate removal performance for Co2+, they suffer from insufficient removal depth due to strongly relying on sole cation-exchange mechanism. To tackle this challenge, we successfully synthesized a series of nitrogen-functionalized NaA zeolites via an in situ strategy. Among them, the imidazoline-functionalized zeolite (IM-NaA) exhibits a distribution coefficient (Kd) of 3.95×l06 mL/g, which is an order of magnitude higher than that of pristine NaA, revealing enhanced affinity toward Co2+ ions. These zeolites also feature rapid adsorption kinetics and satisfied selectivity. X-Ray photoelectron spectroscopy (XPS) analysis confirms that the enhanced capture is achieved through the concurrent processes of Na+/Co2+ exchange and coordination between Co2+ and the functionalized nitrogen sites. This study provides an effective strategy for the rational design of zeolite-based adsorbents for the deep decontamination of cobalt ions.