Preparation, characterization, and application of stable naphthalenediimide‐based metal–organic framework for cooperative capture low concentration uranium from wastewater

Abstract

AbstractExtracting uranium from real water samples remains a great challenge due to low uranium concentration, concentrated competing ions and volumes of water. The design and preparation of uranium adsorbents with high efficiency and affinity are still difficult. Herein, we presented a facile one‐pot strategy to obtain a novel metal organic framework (denoted as Mn‐NDISA) for stable and efficient trapping of low concentration uranium. Mn‐NDISA with a built‐in hydrophobic cavity can boost the absorption affinity to 1.99 × 106 mL g−1 through the cooperative capture composed of electrostatic interaction, coordination force and hydrogen binding. Owing to the coordination‐available oxygen sites in flexible framework, a rapid kinetic equilibrium was achieved in just 25 min. Moreover, these exceptional adsorption features enabled Mn‐NDISA to successfully capture the naturally occurring uranium traces (~ppb) in wastewater samples, making it one of the most influential absorbents toward UO22+ ever reported. The experimental and theoretical studies revealed that the electrostatic attraction came from the surface negatively charged Mn‐NDISA and the positively charged UO22+. The coordination originated from Lewis basic hydroxyl, carbonyl groups, and Lewis acid UO22+, while hydrogen bonds further reinforced the as‐formed uranium binding complex. This research offered a promising cooperative capture strategy to improve the uranium affinity of the pristine MOF for trace contaminants removal in environmental remediation fields.