Defect Remediation of MXene Membranes Facilitated by Intercalation and Coordination Processes for Enhanced Organic Pollutant Removal

Abstract

Two-dimensional (2D) materials, especially titanium carbide (Ti₃C₂T_x) MXene, have emerged as an ideal building block to prepare 2D membranes for water treatment. However, the prepared MXene membranes suffer from stability problems, including horizontal and vertical defects, caused by the nonuniform stacking during the preparation process and the swelling of nanosheets in water. Here, we report the design and fabrication of stable MXene membranes via an intercalation and interfacial cross-linking strategy using phytic acid (PA) and Fe³⁺. PA molecules act as spacer sequences to enlarge the size and stabilize the nanochannels, following coordination with Fe³⁺ to form a coating to cover the defects. The optimized MFP2 membrane displays outstanding water permeability at 115.9 L m^–2 h^–1 bar^–1 (2.5 times improved compared with the MXene membrane) and good selectivity (methyl blue rejection rate: ∼99.8%; Na₂SO₄ rejection rate: <10.0%). Furthermore, the modified membrane shows excellent stability and antifouling performance. This study presents an environmentally friendly and straightforward approach to address the stability issue of MXene-based membranes, providing insights for the design of the next generation of high-performance membranes.