Enhanced selective dye adsorption and oil/water separation using fungi-modified Ti₃C₂T_x MXene-based PVDF membranes

High-performance membranes capable of simultaneously removing dyes and separating oil/water emulsions are critical for water treatment. In this study, poly(vinylidene fluoride) (PVDF) membranes were modified with MXene nanosheets (M1) and fungal chitosan nanofibers (FChNFs, M2) to enhance hydrophilicity, antifouling behavior, and separation efficiency. Extensive characterization through XRD, FTIR, UV-Vis DRS, Raman spectroscopy, SEM, SEM-EDX, TGA, and porosity analysis confirmed substantial enhancements in membrane properties, revealed improved surface wettability, with contact angles decreasing from 84° (pristine PVDF, M0) to 63° (M1) and 72° (M2), and optimized pore structures confirmed by SEM and Elford–Ferry analysis. Pure water flux increased significantly, from 110 L·m⁻²·h⁻¹ (M0) to 1409 L·m⁻²·h⁻¹ (M1), while total hydraulic resistance decreased from 132 10⁻³ to 7.51 10⁻³ m⁻¹. Dye rejection tests showed greater than 90 % removal for both cationic (methylene blue) and anionic (brilliant blue) dyes, demonstrating high selectivity. In oil/water separation using a 200 ppm diesel-in-water emulsion under 0.5–2 MPa, flux improvements reached 31.5 % (M0), 39 % (M1), and 47 % (M2), with hydraulic resistance decreasing from 8 × 10⁸ m⁻¹ (M0) to 3 × 10⁸ m⁻¹ (M2). Flux recovery ratios increased from 91 % to 99 %, indicating reduced fouling and enhanced membrane durability. These results highlight the synergistic effects of MXene hydrophilicity and FChNFs superoleophobicity, which improve permeability, selectivity, and longevity. Overall, MXene- and FChNF-modified PVDF membranes offer a cost-effective, scalable, and high-performance solution for simultaneously removing dyes and separating oil and water for advanced water treatment applications.