Designing nanofiber membranes with dense superhydrophobic skin layers to enhance wetting resistance in membrane distillation

Electrospun nanofiber membranes show significant advantages and potential in membrane distillation (MD) technology due to their high water flux and low mass transfer resistance. However, their further development is limited by the unsatisfactory pore size distribution and insufficient hydrophobicity that makes them prone to wetting. Hence, we prepared TNPs/PDMS colloidal particles by combining TiO 2 nanoparticles (TNPs) and polydimethylsiloxane (PDMS) by a simple method with electrospun nanofiber membranes as the support layer, and prepared nanofiber membranes with dense superhydrophobic skin layer by depositing them on the membrane surface by vacuum filtration. The membrane obtained under optimal conditions had a reduced average pore size of 0.37 μm from 0.84 μm in the original membrane and had a water contact angle higher than 160° and a sliding angle less than 20°, which gave it a liquid entry pressure (LEP) of 1.58 bar. It has shown impressive resistance to wetting when treating 3.5 wt% NaCl solution containing 0.1–0.4 mM SDS and natural seawater . In addition, it has a durability of up to 60 h, a high water flux of 38.7 kg·m −2 ·h −1 , and a retention rate of more than 99.99%.