Water flux enhancement of PVDF membrane by a facile coating method for vacuum membrane distillation

• Published in: Desalination 2022-08, Vol.536, p.115818, Article 115818
• Main Authors: Li, Zhan, Zhang, Pengfei, Guan, Kecheng, Yoshioka, Tomohisa, Matsuyama, Hideto
• Format: Article
• Language: English
• Subjects: Hollow fiber membrane; Ionic liquid; Membrane modification; Polyvinylidene difluoride; Vacuum membrane distillation
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2022.115818

Vacuum membrane distillation (VMD) has received considerable attention from both academia and industry. During VMD, the liquid-vapor interface is supported by a porous hydrophobic membrane to prevent wetting of the membrane pores and allow only vapor to pass through. Therefore, it is advantageous for the production of high-purity water by desalination, and improving the membrane performance has attracted significant attention. In this work, we present a facile method of modifying polyvinylidene difluoride (PVDF) membranes with a fluorine-containing ionic liquid (BPPF6) to improve the membrane hydrophobicity and antiwetting and antifouling properties. The dynamic water contact angle of the membrane increased from 124.5 ± 0.3° to 136.7 ± 0.1°, and the VMD water flux increased by 14.2% for treating 3.5 wt% NaCl aqueous solution at 45 °C. Enhancement of hydrophobicity and water flux by facile coating of ionic liquid. [Display omitted] •Facile coating method to improve hydrophobicity of PVDF membrane•Mitigated pore blocking by IL coating method•Water flux during membrane distillation process improved by hydrophobic coating•Improved anti-wetting and anti-fouling properties by lowering surface free energy