Layered Double Hydroxides Nanosheets In-Situ Anchored on Ultrathin Mxenes for Enhanced U(Vi) and Eu(Iii) Trapping : Excavating from Selectivity to Mechanism

As a rising star among two-dimensional materials, transition metal carbides (MXenes) with prominent characteristic including chemical functionality and high hydrophilic unfold enormous potential for radionuclide sequestration. The design of functionalized MXenes with high uptake capacity and excellent selectivity as well as outstanding anti-interference ability still remains a grand challenge. In this study, a novel MgAl-LDHs functionalized 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 MXenes sheets. Adsorption measurements indicate that the higher porosity and diverse functional groups are conducive for L-TC materials 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 enrichment mechanism is 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 highlights the bright future of the functional MXene materials in the application of radioactive contaminant, especially for the remediation of the high valence radioactive ions