Selective recovery of Re(VII) by nucleobases functionalized cellulose microspheres from the simulated uranium ore leaching solution

From a practical standpoint, it is still challenging to develop adsorbents with high adsorption capacity and outstanding selectivity for rhenium in uranium ore leaching solution. In this study, in order to explore the structure-property relationship, four nucleobases (Adenine, Guanine, Hypoxanthine and Xanthine) were used as functionalization reagents to modify cellulose (MCC-g-GMA-A, MCC-g-GMA-G, MCC-g-GMA-H and MCC-g-GMA-X) via radiation method. The effect of the type of nucleobases on the adsorption performance was evaluated by batch and dynamic experiments. The order of maximum adsorption capacity was MCC-g-GMA-A (194.0 mg g-1) > MCC-g-GMA-G (123.4 mg g-1) > MCC-g-GMA-H (45.59 mg g-1) > MCC-g-GMA-X (23.43 mg g-1), which was associated with the category of nitrogen-functional groups. Different nitrogen-containing functional groups have different degrees of protonation, which leads to differences in the interaction of the adsorbent with Re(VII). Notably, the adsorbents were able to selectively capture trace Re(VII) from the simulated uranium ore leaching solution. The FT-IR, XPS analyses, DFT theoretical calculations exhibited that the adsorption mechanism of nucleobases functionalized cellulose microspheres and Re(VII) was electrostatic interaction. MCC-g-GMA-A and MCC-g-GMA-G exhibited excellent selectivity towards Re(VII), which are potential adsorbents for Re(VII) recovery in uranium ore leaching solutions.