Design of firm-pore superhydrophobic fibrous membrane for advancing the durability of membrane distillation

Abstract Electrospun fibrous distillation membrane (EFDM), owing to its low mass transfer resistance for relatively high-water flux, has attracted significant attention to the treatment of high salinity wastewater with membrane distillation. However, a significant challenge in using EFDM for desalination of high-salinity wastewaters is pore wetting induced by scaling. Herein, we designed a firm-pore superhydrophobic fibrous membrane via a facile and scalable electrospinning in combination with dip-coating methods, which displayed a high-water flux of about 28.5 L/m2·h (ΔT = 40 °C) and unexpected durability (>312 h) in the long-term running of direct contact membrane distillation. Significantly, we also systematically investigate the effect of surface wettability and pore structure on the durability of EFDM. The experiments and simulations demonstrate that the formation of firm-pore among the EFDM has a substantial influence on the membrane durability when desalinating high salinity wastewaters, owing to the avoidance of pore deformation influenced by the feedwaters turbulent on the EFDM surface. Meanwhile, the superhydrophobic surface also helps reducing the contact area between the crystals and the salts to further improve the membrane durability. The theory simulation may provide new insight into designing novel structured fibrous membrane to improve the fibrous membrane stability in MD.