Recovery of rhenium(VII) from synthetic leaching solutions of uranium ore using ionic liquid modified cellulose microsphere adsorbents

Abstract

Although various novel adsorbents with different structures are exploited for rhenium recovery, developing cost-effective micron-sized adsorbents with high adsorption capacity, rapid uptake, and excellent selectivity is still challenging from a practical point of view. In current work, two ionic liquid functionalized cellulose microsphere (ILFC-NO3 and ILFC-Cl) were prepared via radiation technique and their performance for Re(VII) separation was investigated through batch and dynamic experiments. The ILFC-NO3 and ILFC-Cl exhibited not only high adsorption capacity (ILFC-NO3 of 581 mg/g and ILFC-Cl of 552 mg/g) for the high concentration of Re(VII) but also fast adsorption rate with equilibrium time of 1.5 h. Adsorption-desorption experiments indicated that both ILFC-NO3 and ILFC-Cl had excellent reusability and could be recycled four times with negligible capacity loss. Their adsorption mechanism could be explained as the combination of ion exchange and reduction. Furthermore, ILFC-NO3 could recover trace Re(VII) at 10 ppb from aqueous solution with the enrichment factor of 417. The ILFC-NO3 also exhibited excellent Re/U selectivity from synthetic uranium underground leaching solution in which the concentration of U was 200 times higher than Re(VII). This work provided two micron-sized adsorbents with superior adsorption capacity for Re(VII) recovery, which are promising candidate adsorbents for Re(VII) recovery in practical applications.