Dual-layer hydrophilic/hydrophobic PVDF-HFP electrospun membranes synthesis for Air Gap Membrane Distillation (AGMD)

The main challenges for membranes used in membrane distillation (MD) are well-designed porous structure and hydrophobic surface property. Hydrophobic nanofiber membranes possess high hydrophobicity, high surface porosity and adjustable pore sizes and membrane thickness, which make them an attractive candidate as MD membranes. Compared to traditional phase inversion techniques for membrane fabrication, electrospinning allows the formation of interconnected pores with uniform pore size and porosities exceeding 90%.In this study, a electrospun nanofiber polyvinylidenefluoride-co-hexafluoropropylene (PVDF-HFP) flat-sheet composite membrane using commercial hydrophilic polyester nonwoven as a support layer was prepared for MD applications. This composite nanofiber membrane has been characterized by a series of measurements (scanning electron microscopy (SEM),contact angle and porosity measurements and air gap MD (AGMD) setup were used) and benchmarcked against commercial PVDF flat-sheet membrane for MD applications. The electrospun layer of the membrane which fabricated by using optimized process parameters was obtained with mean pore size, porosity, contact angle, and thickness of 435 nm, 81%, 140° and 105 μm, respectively. Fabricated membrane was tested for desalination by air-gap MD and water flux value of 13.2 L/m2.h was obtained with a salt rejection of 98.4%. The present composite nanofiber membrane showed better flux performance and salt rejection compared to a commercial flat-sheet membrane (Flux = 8 L/m2h and SR = 95% ) The result suggest the potential of the nanofibrous membrane for AGMD applications.

کلیدواژه ها:

PVDF-HFP ، Electrospun membrane ، Nanofiber ، Membrane distillation (MD