The formation potential of disinfection by-products of Ti3C2Tx MXene

Abstract

Owing to the outstanding properties, including non-toxicity, large surface area, bactericidal ability, and versatile surface chemistry, Ti3C2Tx MXene-based adsorbents and membranes have been widely explored in drinking water and wastewater treatment. At the same time, with the rapid increase in MXene applications, it is inevitable that MXene will find its way into water and wastewater treatment systems. It is therefore imperative to assess its potential for disinfection by-products (DBPs) formation and physicochemical transformation by chlorination. This study demonstrated that Ti3C2Tx Mxene has a high formation potential of DBPs including trichloromethane (TCM), dichloroacetonitrile (DCAN) and dichloroacetic acid (DCAA) during the chlorination and chloramination procedures. Few-layered Ti3C2Tx with a larger specific surface area produced more DBPs. The concentrations of TCM and DCAN increased monotonically with the prolongation of chlorine contact time, while the amount of DCAA tended to be stable after 10 h of chlorination. Moreover, the effects of chlorine dose were also considered to better understand the pattern of DBPs formation by Ti3C2Tx MXene. The possible mechanism of DBPs formation was deduced by analyzing the results of FTIR, Raman and XPS before and after chlorination. The DBPs were primarily formed with the destruction of TiC bond by chlorine with the concurrent formation of TiO2. The findings of this research add to the understanding of the potential for DBPs formation from carbon-containing nanomaterials in water treatment systems and shed light on the environmental potential risk of MXene.