Novel thin-film nanocomposite membranes with crosslinked polyvinyl alcohol interlayer for Perfluorinated Compounds (PFCs) removal

Abstract

Conventional polyamide-based interface polymerized nanofiltration (NF) membranes exhibit trade-off characteristics between water permeability and salt selectivity. The introduction of nanomaterial interlayers into thin-film composite (TFC) membranes is expected to overcome the limitation. Herein, a novel membrane was constructed via coating a polyvinyl alcohol (PVA) interlayer on the PES supporting film. Trace amounts of MXene nanosheets were used to form a barrier to avoid the occupancy of large pores by PVA. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectra, water contact angle (WCA), zeta potential, and other characterizations were used to evaluate the chemical and physical properties of the prepared membranes. Due to the PVA hydrophilicity, the composite membranes achieved higher hydrophilicity. Besides, the electronegativity enhancement and roughness improvement facilitate the film to have better application prospects. At the lab scale, the optimized membranes achieved a high-water flux of 22.8 L m⁻2h⁻1bar⁻1 and a 94.5% MgSO4 rejection. The typical kinds of PFCs, including PFOA, PFOS, PFHxA and PFBA, were quantitatively evaluated and analyzed by electrostatic interaction. The excellent performance was maintained in the case of environmental changes owing to the stableness of the PVA interlayer. This study provides a new avenue for fabricating robust NF membranes for actual production.