Layered double hydroxides nanosheets in-situ anchored on ultrathin MXenes for enhanced U(VI) and Eu(III) trapping: Excavating from selectivity to mechanism

• L-TC was synthesized via an in-situ anchoring strategy of LDHs on MXenes. • L-TC with outstanding performance for U(VI) and Eu(III) trapping. • Metal-oxygen and hydroxyl sites are the predominant binding sites. • L-TC exhibited excellent adsorption selectivity for high valence radioactive ions. As a rising star among two-dimensional materials, transition metal carbides (MXenes) with prominent characteristic including chemical functionality and high hydrophilic unfolded huge potential for radionuclide sequestration. The design of functionalized MXenes with high uptake capacity and excellent selectivity as well as outstanding anti-interference ability still remained a grand challenge. In this study, a novel MgAl-layered double hydroxides (LDHs) ultrathin Ti 3 C 2 T x MXene (L-TC) nanosheets with a typical flower-shaped structure was designed, and tested for U(VI) and Eu(III) elimination. The in-situ anchoring strategy of LDHs nanosheets provided an effective path for overcoming the demerits of limited layer space, insufficiency action sites and poor stability of pristine Ti 3 C 2 T x sheets. Additional, adsorption measurements indicated that the higher porosity and diverse functional groups were conducive for L-TC to capture U(VI) and Eu(III). Impressively, L-TC exhibit exceptional trapping capacities toward U(VI) (241.0 mg g −1 ) and Eu(III) (97.1 mg g −1 ), which were significantly higher than those of the original Ti 3 C 2 T x and LDHs. More importantly, L-TC exhibited high uptake selectivity, fast rapid removal kinetics and excellent anti-ion interference. The adsorption mechanism was clearly elucidated and visualized by spectral analysis, revealing a unique U(VI) and Eu(III) uptake selectivity driven by metal–oxygen sites of L-TC via complexation action. This work herein highlights the bright future of the functionalized MXene materials in the application of radioactive contaminant, especially for the remediation of the high valence radioactive ions.