Efficient removal of Sr 2+ and Cs + from aqueous solutions using a sulfonic acid-functionalized Zr-based metal–organic framework

A stable and highly efficient adsorbent was successfully fabricated by the modification with UiO-66-NH2 with –SO3H functional groups using a facile and scalable tactic. The physical and chemical properties of UiO-66-NH–SO3H-3 were extensively characterized. The maximum removal capacities are 173.9 and 233.4 mg g−1 for Sr2+ and Cs+ at 298 K, respectively. More importantly, UiO-66-NH–SO3H-3 can remove Sr2+ and Cs+ selectively even in the presence of different coexisting ions due to the –SO3H functional groups. Coordination with –SO3H functional groups is main adsorption mechanism while electrostatic interaction and ion exchange may be also involved in the adsorption process.