Superhydrophobic PVDF membrane modified by dopamine self-polymerized nanoparticles for vacuum membrane distillation

Abstract

Membrane fouling and wetting are significant issues that limit the practical application of vacuum membrane distillation (VMD). In this study, we employed polydopamine nanoparticles (PDANPs) and polydimethylsiloxane (PDMS) to hydrophobically modify pristine polyvinylidene fluoride (PVDF) membranes to improve the overall resistance of the membrane to contamination. The modified membranes have a high contact angle of 162.5° and a low sliding angle (<10°) with excellent superhydrophobic properties. The surface morphology, chemical composition, and stability of the modified superhydrophobic membranes were systematically analyzed. Additionally, the superhydrophobic membranes demonstrated stable flux and excellent salt rejection (99.9%) in a 24 h VMD test in hypersaline and hard water treatment, indicating outstanding anti-wetting and anti-fouling performance. The findings demonstrate that modified membranes have a great potential in long-term VMD practical applications.