Abstract
Although two-dimensional titanium carbide (Ti3C2T x MXene) has emerged as a shining star material in various communities, its environmental behaviors and fate remain unknown. Herein, the colloidal properties and stability of Ti3C2T x MXene are explored in aquatic systems for the first time, considering the roles of solution chemistry conditions (e.g., pH, ionic types, and strength). It was found that pH had no effect on the stability of Ti3C2T x in the range of 5.0–11.0, whereas ionic valence and concentrations displayed significant effects on the aggregation behavior of Ti3C2T x . By employing time-resolved dynamic light scattering measurements, the critical coagulation concentration (CCC) value of Ti3C2T x was determined to be 12 mM for NaCl. The divalent cations Ca2+ and Mg2+ exhibited higher destabilizing capacity to Ti3C2T x , as evidenced by the lower CCC values (0.3 and 0.4 mM for CaCl2 and MgCl2, respectively) and faster coagulation rates. Long-term stability studies implied that Ti3C2T x MXene was less likely to be transported over long distances in the synthetic or natural waters. These findings provided significant insights into the fate and transport of Ti3C2T x in the aquatic environment.