Enhanced iodine capture via covalently integrated NH₂-UiO-66@ZA-COF hybrid structures

Abstract

Nuclear power remains a crucial energy source, yet the management of radioactive waste, particularly iodine isotopes, presents significant environmental and health concerns due to their volatility and long half-life. Developing advanced materials for effective iodine sequestration is vital for ensuring the safe disposal of nuclear waste. Metal-Organic Framework (MOF)@Covalent Organic Framework (COF) hybrid materials offer a promising strategy, combining the high porosity and stability of MOFs with the tunable functionality of COFs. In this study, we introduce NH₂-UiO-66@ZA-COF, a novel MOF@COF hybrid synthesized via the in-situ growth of a ZA-COF shell on an NH₂-UiO-66 core using a Schiff-based reaction. This covalently bonded core-shell structure enables fine-tuned interface properties that significantly enhance iodine adsorption capacity. Our results demonstrate that NH₂-UiO-66@ZA-COF exhibits an exceptional iodine vapor uptake of 5.63 g⋅g⁻¹, surpassing previously reported MOF-COF hybrids such as NH₂-UiO-66@Br-COFs (3.73 g⋅g⁻¹) and UiO-66-NH₂@TAPT-COF (0.24 g⋅g⁻¹). Moreover, NH₂-UiO-66@ZA-COF hybrids display outstanding reusability, retaining over 94% of their iodine adsorption capacity after five cycles. The material maintains its structural integrity under harsh environmental conditions, demonstrating long-term stability, scalability, and cost-effectiveness. This study contributes to the advancement of sustainable radioactive waste management technologies by offering an efficient and reusable material for iodine capture, reducing the environmental impact of nuclear waste storage while providing a scalable and cost-effective solution for industrial applications. These findings highlight the potential of NH₂-UiO-66@ZA-COF as a high-performance material for radioactive iodine sequestration, paving the way for more sustainable nuclear waste management solutions.