Efficient Removal of [UO], Cs, and Sr Ions by Radiation-Resistant Gallium Thioantimonates.

Unconventional ion exchangers can achieve efficient removal of [UO], Cs, and Sr ions from complex aqueous solutions and are of great interest for environmental remediation. We report two new gallium thioantimonates, [MeNH][GaSbS]·HO (FJSM-GAS-1) and [EtNH][GaSbS]·HO (FJSM-GAS-2), which present excellent ion exchange properties for [UO], Cs, and Sr ions. They exhibit high ion exchange capacities for [UO], Cs, and Sr ions ( q = 196 mg/g, q = 164 mg/g, and q = 80 mg/g for FJSM-GAS-1, q = 144 mg/g for FJSM-GAS-2) and short equilibrium times for [UO] ion exchange (5 min for FJSM-GAS-1 and 15 min for FJSM-GAS-2, respectively). Both compounds display active ion exchange with [UO] in the pH range of 2.9-10.5. Moreover, the sulfide compounds could maintain high distribution coefficients K even in the presence of excess Na, Ca, and HCO. The distribution coefficient K of 6.06 × 10 mL/g exhibited by FJSM-GAS-1 is the highest among the reported U adsorbents. The [UO]-laden products can be recycled by conveniently eluting the uranium with a low-cost method. These advantages combined with facile synthesis, as well as β and γ radiation resistance, make FJSM-GAS-1 and FJSM-GAS-2 promising for selective separations in nuclear waste remediation.