Efficient iodine capture from water using a functionalized covalent organic framework

Abstract

The development of effective iodine adsorbents is a vital and challenging goal in radioactive waste management. In this study, we functionalized a covalent organic framework (COF-366) with amidoxime groups (AO) to create a new porous organic polymer (POP-AO), designed specifically for iodine capture. We systematically examined several key factors, including contact time, pH, initial iodine concentration, and the effect of competing ions on adsorption performance. Notably, POP-AO achieved an impressive iodine uptake of 909.1 mg g⁻¹, exceeding many previously reported materials. This high capacity mainly results from Lewis acid–base interactions between the electron-rich AO groups and electrophilic iodine. Kinetic studies indicated that the adsorption follows a pseudo-second-order model. Moreover, the material maintained its high capacity of 909.1 mg g⁻¹ after seven regeneration cycles, demonstrating excellent reusability. This research not only offers a promising strategy for radioactive iodine remediation but also establishes POP-AO as a durable and effective adsorbent for practical use.