Pb²⁺ Adsorption with V₂CT_<i>x</i> MXenes for Water Treatment

Water contamination from industrial activities has been a major problem throughout the world. Typically, lead ions (Pb2+) are recognized as a persistent contaminant posing a great threat to our environment and human health, which urgently needs to be solved. Adsorption is one of the most effective ways to solve it. MXenes show great potential for applications in the fields of adsorption due to their large specific surface area, excellent hydrophilicity, and structural stability. In this work, a series of V2CTx MXenes including multilayered V2CTx MXene (M-V2C), alkalized V2CTx MXene (A-V2C), and single-layer V2CTx MXene (S-V2C) were prepared by an etching method to apply for Pb2+ adsorption. Compared to M-V2C and A-V2C, S-V2C not only had the highest adsorption efficiency under the same conditions but also exhibited a wide pH adsorption ability in the range of 1–14, which cannot be achieved by other adsorbents. In addition, it showed great cycle performance after 10 cycles and selective adsorption of Pb2+ in the presence of other ions. Factors affecting the Pb2+ adsorption capacity of V2C and related mechanisms were also thoroughly investigated. This work demonstrates for the first time that S-V2C is a novel adsorbent material with excellent pH tolerance, regeneration performance, and selective adsorption ability, which shed bright light on the related applications.