Fabrication and characterization of electrospun superhydrophobic PVDF-HFP/SiNPs hybrid membrane for membrane distillation

摘要

Graphical abstractDisplay OmittedHighlights?PVDF-HFP/SiNPs hybrid nanofibrous membranes were electrospun for DCMD.?The influence of hydrophobic SiNPs on membrane properties was investigated.?The hybrid nanofibrous membrane presented a superhydrophobic surface.?A high permeate flux was obtained for the hybrid nanofibrous membrane.?The hybrid membrane exhibited stable permeability and superhydrophobicity.AbstractThe poly(vinylidene fluoride-co-hexafluropropylene) (PVDF-HFP)/Silica nanoparticles (SiNPs) flat-sheet hybrid membranes were fabricated for membrane distillation via electrospinning, and the effects of SiNPs on the resultant membranes properties were investigated. The electrospun nanofibers membranes presented a three-dimension interconnected open morphology. Although the SiNPs had no significant effect on the crystalline form of the PVDF-HFP polymer in the hybrid membranes, the membrane surface became rougher and exhibited a hierarchical stratum structure due to overlapping nanofibers and the presence of beads-on-string with the SiNPs addition, which made the superhydrophobic membrane surface formation. The SiNPs addition declined membrane porosity, while enlarge pore diameter and increased membrane thickness. However, the liquid entry pressure of water of the hybrid membrane was not significantly influenced by the SiNPs addition. The electrospun membranes were tested through direct contact membrane distillation using 35g/L NaCl solution as feed, and the highest permeate flux bout 48.6kg/m2h was obtained and the salt rejection maintained 99.99%. The 240h continuous desalination application demonstrated the stable permeability of the electrospun hybrid membrane, and the membrane hydrophobicity can also maintained well with long-time immersion in salt solution. The results indicated the potential of the electospun superhydrophobic PVDF-HFP/SiNPs hybrid membrane for membrane distillation application.]]>