Reductive Sequestration of Toxic Bromate from Drinking Water using Lamellar Two-Dimensional Ti3C2TX (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 (Ti3C2Tx) 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 Ti3C2Tx nanosheets. In this reduction, the Ti-C active layer of Ti3C2Tx was oxidized and formed TiO2 nanocrystals, while bromate reduced to bromide via a self-reaction process. Reduction performance of the Ti3C2Tx nanosheets was evaluated with respect to the concentration of MXene, time, pH, and temperature. The MXene showed excellent reduction of bromate (similar to 321.8 mg BrO3-/g Ti3C2Tx) within 50 min, at pH 7 and 25 degrees 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.