ANF/BN thin-film composite membranes for efficient organic solvent nanofiltration

Two-dimensional (2D) nanomaterial-based membranes, such as hexagonal boron nitride nanosheets (BNNS), offer exceptional permeance for organic solvent nanofiltration (OSN) but suffer from poor mechanical stability under pressure. To address this, we integrated aramid nanofibers (ANFs) with ball-milled BNNS to construct mixed-dimensional thin-film composite membranes (ABN) with enhanced structural robustness and separation performance. The ABN membranes exhibit a tunable thickness (∼1.17 μm), surface roughness (∼82 nm), and contact angle (∼81°). A representative ABN membrane achieved ethanol flux of 104 L m −2 h −1 at 1 bar, increasing to 164 L m −2 h −1 at 4 bar, with Evans blue rejection slightly decreasing from 96 % to 92 %. The membranes also showed high permeance in methanol and acetone, reversible deformation under pressure up to 10 bar, and stable performance over 24 h in ethanol and under mildly acidic conditions. This study presents a mechanically reinforced, high-performance OSN membrane platform that overcomes the pressure fragility of conventional 2D systems, offering strong potential for practical solvent separation applications. • Thin film ANF/BN composite membranes exhibit high-flux performance for organic solvent nanofiltration. • Deformed ANFs enhance strength and enable reversible channel deformation under 10 bar. • The membranes achieve a flux of 164 L m 2 h −1 in ethanol at 4 bar, with a 92 % rejection of Evans blue dye molecules. • These membranes demonstrate excellent chemical stability and outstanding anti-fouling properties.