Rational Construction of Porous Metal–Organic Frameworks for Uranium(VI) Extraction: The Strong Periodic Tendency with a Metal Node
Zhi‐Hui Zhang, Jian‐Hui Lan, Li‐Yong Yuan, Pan‐Pan Sheng, Ming‐Yang He, Lirong Zheng, Qun Chen, Zhifang Chai, John K. Gibson, Wei‐Qun Shi
Abstract
Although metal–organic frameworks (MOFs) have been reported as important porous materials for the potential utility in metal ion separation, coordinating the functionality, structure, and component of MOFs remains a great challenge. Herein, a series of anionic rare earth MOFs (RE-MOFs) were synthesized via a solvothermal template reaction and for the first time explored for uranium(VI) capture from an acidic medium. The unusually high extraction capacity of UO22+ (e.g., 538 mg U per g of Y-MOF) was achieved through ion-exchange with the concomitant release of Me2NH2+, during which the uranium(VI) extraction in the series of isostructural RE-MOFs was found to be highly sensitive to the ionic radii of the metal nodes. That is, the uranium(VI) adsorption capacities continuously increased as the ionic radii decreased. In-depth mechanism insight was obtained from molecular dynamics simulations, suggesting that both the accessible pore volume of the MOFs and hydrogen-bonding interactions contribute to the strong periodic tendency of uranium(VI) extraction.