In a paper to be published in the forthcoming issue in NANO, researchers from China have proposed a way to reduce Uranium concentration in contaminated water. As an essential nuclear fuel, Uranium has been greatly used an inevitably released to the environment. Without proper disposal, exposure to uranium can result in serious harms to the ecology and health of humans.
Mesoporous SBA-15 with ordered mesostructures, high surface areas and large pore sizes have been applied to concentrate U(VI) from aqueous solutions. The exploration of SBA-15 with higher performances also keeps developing. For instance, the synthesis of functional SBA-15 with organic ligands containing N, O, S and P elements, and with controllable morphologies (e.g., rods, plates, and fibers) and tunable mesostructures have also been reported. However, the comprehensive evaluation of structure-composition-function relationships, including the interconnected influence of textural characteristics of sorbents and the interaction mechanism of U(VI)-surface modified chemical groups, has not been fully studied yet.
This paper investigates how the synergistic integration of pore mesochannels and surface functionalization of SBA-15 enables high-performance U(VI) sorption. In this study, we report the rapid sorption of U(VI) with high capacities and selectivity by amidoxime functionalized ordered mesoporous SBA-15 with two typical morphologies (i.e., rods and plates) via a post-grafting method. The results show that the mesostructures including morphologies and pore length of SBA-15 perform the dominant function for the fast sorption kinetics (10 min for plates, 20 min for rods), while the modified amidoxime groups make excellent U(VI) sorption capacities (646.2 mg/g for plates, 499.8 mg/g for rods at pH 5.0 and T 298.15 K) and high selectivity possible. U(VI) adsorbed amidoxime-functionalized SBA-15 can also be effectively regenerated by HCl solutions and reused well after six cycles, exhibiting favorable potentials for the uptake of radionuclides in real environmental management.
