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

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 degrees to 136.7 +/- 0.1 degrees, and the VMD water flux increased by 14.2% for treating 3.5 wt% NaCl aqueous solution at 45 degrees C.

Automated summary

Vacuum membrane distillation (VMD) is an important technology for the production of high-purity water. Researchers have modified the membrane to improve its performance, resulting in increased water flux and improved hydrophobic properties.