Efficient and selective sorption of uranyl by hydrated Ti3C2TX-Li agglomerates

Abstract

There is a demand to develop highly efficient and selective materials for removal of uranyl species from aqueous solutions. Herein, titanium carbide (Ti3C2TX-Li) agglomerates composed of plate fragments were synthesized by etching MAX (Ti3AlC2) powders in HF/LiCl solution. Compared to reference samples, hydrated Ti3C2TX-Li showed the best affinity for U(VI) (qm = 1.12 mmol/g) and a sorption capacity>90% (0.04–0.2 mM initial U(VI)). The efficient sorption capacity of hydrated Ti3C2TX-Li was attributed to larger interlayer spacing and smaller lateral dimensions of the plate fragments (0.1–3 μm), which facilitated the U(VI) species to reach deeper sorption sites in the interlayer compared with the accordion-like Ti3C2TX. Uranium(VI) exhibited excellent selective sorption to hydrated Ti3C2TX-Li in the presence of Sm3+, Nd3+, Co2+, Cd2+, Zn2+, and Cu2+ (nitrates), due to the surface-mediated reduction of U(VI) to U(IV) and the oxidation of the Ti component of MXene.