Pb<sup>2+</sup> Adsorption with V<sub>2</sub>CT<sub><i>x</i></sub> MXenes\nfor Water Treatment

Water contamination from industrial activities has been\na major\nproblem throughout the world. Typically, lead ions (Pb<sup>2+</sup>) are recognized as a persistent contaminant posing a great threat\nto our environment and human health, which urgently needs to be solved.\nAdsorption is one of the most effective ways to solve it. MXenes show\ngreat potential for applications in the fields of adsorption due to\ntheir large specific surface area, excellent hydrophilicity, and structural\nstability. In this work, a series of V<sub>2</sub>CT<sub><i>x</i></sub> MXenes including multilayered V<sub>2</sub>CT<sub><i>x</i></sub> MXene (M-V<sub>2</sub>C), alkalized V<sub>2</sub>CT<sub><i>x</i></sub> MXene (A-V<sub>2</sub>C), and single-layer\nV<sub>2</sub>CT<sub><i>x</i></sub> MXene (S-V<sub>2</sub>C) were prepared by an etching method to apply for Pb<sup>2+</sup> adsorption. Compared to M-V<sub>2</sub>C and A-V<sub>2</sub>C, S-V<sub>2</sub>C not only had the highest adsorption efficiency under the\nsame conditions but also exhibited a wide pH adsorption ability in\nthe range of 1–14, which cannot be achieved by other adsorbents.\nIn addition, it showed great cycle performance after 10 cycles and\nselective adsorption of Pb<sup>2+</sup> in the presence of other ions.\nFactors affecting the Pb<sup>2+</sup> adsorption capacity of V<sub>2</sub>C and related mechanisms were also thoroughly investigated.\nThis work demonstrates for the first time that S-V<sub>2</sub>C is\na novel adsorbent material with excellent pH tolerance, regeneration\nperformance, and selective adsorption ability, which shed bright light\non the related applications.