The effect of chemistry of nanoparticle modifier groups on the PVDF membranes for membrane distillation

Recently, the synthesis of nanoparticles including their hydrophobic modifications for the synthesis of membranes for membrane distillation has shown incredible improvements in the; intrinsic physical and morphological properties, transmembrane flux, rejection, and life of the membrane. This study evaluates the effect of three different hydrophobic nanoparticles on the morphological, physical, and hydrophobic characteristics of the PVDF membranes. The octadecyl dihydrogen phosphate modified calcium carbonate (OC), octadecylamine modified Montmorillonite (OM), and Heptadeca- fluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane modified silica (HS) nanoparticles were incorporated into the polyvinylidene difluoride (PVDF) membrane matrix in different compositions. The real seawater desalination performance of the newly synthesized membranes was tested in direct contact membrane distillation configuration for desalting the Arabian Gulf Seawater as feed. The PVDF membrane comprised of HS filler was the top performer with the highest water vapor flux of 42.3 LMH owing its CF₂ functional groups, small chain length, small size and high electronegativity of F atoms, a stable C–F bonding interaction, and a low surface energy C–F compared to OC and OM nanoparticles. Also, HS incorporated membrane witnessed the highest anti-wetting and reliability by rejecting >98.7% ions from seawater.