Large-Scale MXene Membrane Fabrication via Nonsolvent Phase Separation

Over the past decade, 2D MXenes have garnered tremendous attention for membrane applications owing to their exceptional hydrophilicity, tunable surface chemistry, and antifouling properties. However, translating MXene-based membranes from laboratory demonstrations to practically relevant manufacturing remains challenging because scalable fabrication routes are still limited. Herein, we demonstrate a roll-to-roll nonsolvent-induced phase separation (R2R-NIPS) process for fabricating Ti₃C₂T_x/polysulfone (PSF) mixed-matrix ultrafiltration membranes in large sheet format (196 × 84 cm; geometric area ≈1.65 m²). Incorporation of 1 wt% MXene produced more open and interconnected membrane substructures, enhanced apparent wettability (contact angle reduced from 90° for PSF to 62°), a more negative surface charge, and subsurface flake embedding confirmed by characterization. These features yielded a water flux of 206 LMH (31% higher than pristine PSF) with 97.6% humic acid rejection (n = 3 batches, p < 0.01 for flux; p < 0.05 for rejection), while batch-to-batch variability remained <5%. Rather than claiming a measured thermodynamic phase diagram, we interpret the observed morphology as consistent with faster demixing during R2R-NIPS. This processing methodology-documenting practical parameter choices such as casting speed, wet thickness, and bath circulation-provides a feasible route toward larger-scale MXene membrane production for water purification.