Novel 2D Magnetic Titanium Carbide for Methylene Blue Removal over a Wide pH Range: Insight into Removal Performance and Mechanism

Two-dimensional (2D) layer-structured titanium carbide MXenes (e.g., 2D Ti3C2 MXene) have received tremendous attention owing to their excellent properties and unique 2D planar topology. Nevertheless, there are still several challenges to be addressed for well dispersibility and easy separation from a heterogeneous system, hindering the practical applications. Herein, 2D Ti3C2 MXene, as the most typical member of 2D MXenes, is functionalized with magnetic Fe3O4 nanoparticles via an in situ growth approach (designated as MXene@Fe3O4), which exhibits the intriguing phenomenon on methylene blue (MB) adsorption in the environmental remediation realm. The maximum adsorption capacity of the MXene@Fe3O4 composites for MB is calculated to be 11.68 mg·g–1 by a Langmuir isotherm model. A thermodynamic study of the adsorption demonstrates that the reaction process is exothermic and entropy-driven. Attractively, the removal process is a pH-independent process, and the optimal MB adsorption capacity is achieved at pH ...