Preparation and characterization of PDMS-PVDF hydrophobic microporous membrane for membrane distillation

• PDMS-PVDF blend hydrophobic microporous membranes were prepared by the NIPS process.
• PDMS-PVDF membranes exhibited both finger-like and sponge-like pore structures.
• The blend membranes exhibited a striking VMD performance as compared with PVDF membrane.

PDMS-PVDF hydrophobic microporous membranes were prepared through NIPS process for the vacuum membrane distillation (VMD). The influences of PDMS/PVDF mass ratio on the morphology, crystalline structure, pore structure, hydrophobicity, mechanical characteristics and permeability of the membranes were investigated. Compared with the finger-like pore PVDF membrane, PDMS-PVDF membrane had two kinds of pores which are finger-like pore and sponge-like pore and had higher porosity, bigger mean pore size, higher hydrophobicity, stronger mechanical properties and better VMD performances. The VMD experiment for a 20 g/L NaCl aqueous was carried out at feed temperature 50 °C and permeate-side vacuum 80 kPa. Compared with PVDF membrane, PDMS-PVDF blend membrane exhibited striking advantages in permeation performances, and when PDMS/PVDF mass ratio was 1:5, the maximum permeate flux was 15.23 kg/(m2·h), which was equal or even better than most results of the other studies.

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