Regenerable and stable biomimetic hydroxyl-modified metal-organic frameworks for targeted uranium capture

Abstract By mimicking the binding motifs of bioreceptors, we have developed a series of multiple functional uranium adsorbents to meet this criterion: positioning direct chelation sites and hydrogen-bonding sites inside deep hydrophobic cavity of naphthalene diimide (NDI) MOFs. Benefiting from well-designed specific microenvironment namely the regular spatial structure and an unusual synergy from hydroxyl and carbonyl groups, the easy-prepared and stable MOF shows enhanced comprehensive performance. Representatively, the MOF CaNDI-oOH shows outstanding performance towards uranium enrichment with chemical and radiation stability, exceptional uptake capacity (572 mg g-1), fast kinetics (within 25 min), high anti-interference ability (the concentration of competitive ions exceeds 10 times), excellent reusability (at least 4 circles). Specifically, this adsorbent is able to reduce uranium in uranium-containing water samples to 3.27 ppb within 30 min, highlighting the potential application in radionuclide removal from wastewater. The experiment results and DFT calculation suggest biomimetic multiple interactions are responsible for high performance uranium capture. The cooperative interactions strategy established here reveals a new paradigm in enhanced uranium extraction for pristine MOFs with limited uranium affinity.