Micro-oxidized MXene membrane with superior stability for efficient water purification

MXene (Ti₃C₂Tx) can be utilized to modify water-related membranes to provide favorable properties, including pronounced hydrophilicity and chemical stability, and higher flux compared with GO membranes. In order to improve the properties of composite membrane properties, new methods of modifying MXene membranes have been receiving increasing attention. Nowadays, the performance of MXene membranes is mainly limited by methods of modification and stability. In this study, a high-performance composite membrane utilizing MXene (Ti₃C₂T_x) was fabricated through a mild and rapid pre-oxidation method. The composite membrane had a high water permeability of ∼690 L m⁻² h⁻¹ MPa⁻¹, a dye rejection of ∼99.9 % and an adsorption rate of only 1 %. Compared with the unoxidized MXene membranes, the composite membranes showed improved the permeation inhibition efficiencies of 42.39 % and 37.51 % for NaCl and MgCl₂, respectively. The rapid oxidation by Fe(III) formed a composite nano-layer of anatase TiO₂ and magnetite Fe₃O₄ supported by carbon sheets which protected the internal Ti₃C₂T_x from further oxidation. The characteristic morphology of a two-dimensional, layer by layer material, was maintained. In addition, the composite membrane demonstrated long-term stability in terms of both structure/appearance and flux in water. Therefore, this work presents new thoughts on the structural tuning and performance optimization of MXene (Ti₃C₂T_x) membranes.