Reductive Sequestration of Toxic Bromate from Drinking Water using Lamellar Two-Dimensional Ti₃C₂T_X (MXene)

Removal of toxic byproducts such as bromate (BrO₃^-) from drinking water is a vital process. Two-dimensional (2D) titanium carbide also known as MXene (Ti₃C₂T_X) was proven a promising candidate for efficient reduction of metal ions. Herein, we report for the first time the simple method for efficient reduction of toxic bromate to bromide in water using 2D Ti₃C₂T_X nanosheets. In this reduction, the Ti-C active layer of Ti₃C₂T_X was oxidized and formed TiO₂ nanocrystals, while bromate reduced to bromide via a self-reaction process. Reduction performance of the Ti₃C₂T_X nanosheets was evaluated with respect to the concentration of MXene, time, pH, and temperature. The MXene showed excellent reduction of bromate (∼321.8 mg BrO₃^-/g Ti₃C₂T_X) within 50 min, at pH 7 and 25 °C. Furthermore, MXene nanosheets exhibited excellent sequestration performance toward bromate in comparison with other similar materials. The high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis confirmed the reduction of bromate and subsequent oxidation of MXene to form TiO₂ nanocrystals and Br^-. This makes them attractive reductant materials for the efficient removal of other toxic oxides present in water systems.