Novel Two-Dimensional Magnetic Titanium Carbide for Methylene Blue Removal over a Wide pH Range: Insight into Removal Performance and Mechanism

作者：Ping Zhang, Mingxue Xiang, Huiling Liu, Chen‐Kai Yang, Shuguang Deng · 发表于：ACS Applied Materials & Interfaces · 年份：2019 · DOI：10.1021/acsami.9b04222 · 被引用次数：154 · 研究领域：MXene and MAX Phase Materials、Graphene and Nanomaterials Applications、Graphene research and applications

Two-dimensional (2D) layer-structured titanium carbide MXenes (e.g., 2D Ti 3 C 2 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 Ti 3 C 2 MXene, as the most typical member of 2D MXenes, is functionalized with magnetic Fe 3 O 4 nanoparticles via an in situ growth approach (designated as MXene@Fe 3 O 4 ), which exhibits the intriguing phenomenon on methylene blue (MB) adsorption in the environmental remediation realm. The maximum adsorption capacity of the MXene@Fe 3 O 4 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 = 3 or 11, which is ascribed to electrostatic interactions and the hydrogen bond effect. X-ray diffraction, Fourier transform spectroscopy, X-ray photoelectron spectroscopy, and density functional theory calculation results reveal that the adsorption process is based on a combination of Ti–OH···N bonding, electrostatic attraction, and reductivity. Furthermore, multiple cycle runs demonstrate an excellent stability and reusability of MXene@Fe 3 O 4 composites....