Activated carbon enhanced superhydrophobic thermally rearranged nanofibrous membranes for direct contact membrane distillation

Superhydrophobic thermally rearranged (TR) nanofibre membranes are developed for membrane distillation (MD) to enable energy-efficient water desalination. Hydrophobic activated carbon (AC) particles are incorporated into porous nanofibre membranes to enhance water vapour transport by enhancing membrane hydrophobicity through favourable interactions with non-polar organic species. The composite membranes are fabricated via electrospinning of polyimide precursors with AC particles, followed by thermal conversion to form TR nanofibre membranes. This conversion rearranges the polymer backbone into polybenzoxazole, inducing robust superhydrophobicity and chemical stability. The resulting TR nanofibre membranes exhibited improved wetting resistance, enhanced desalination performance, and potential scalability for sustainable water treatment. Notably, the composite nanofibre membranes containing 3.0 wt% of AC (TR-AC-3.0) achieved a high water flux of 76.0 kg m −2 h −1 with a salt rejection rate of 99.99% when tested using a simulated seawater (3.5 wt% NaCl) at 70 °C in direct contact MD. Our approach shows a promising pathway toward designing high efficiency and durable MD membranes that address global challenges in freshwater production. • Superhydrophobic thermally rearranged nanofibre membranes are developed for direct contact membrane distillation. • Activated carbon embedded in nanofibres enhances membrane hydrophobicity, increasing water flux. • At higher AC loadings, performance declines due to reduced porosity by excess particles.