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۱Dual–layer hydrophilic\hydrophobic PVDF–HFP electrospun membranes synthesis for Air Gap Membrane Distillation (AGMD)
اطلاعات انتشار: دومین همایش ملی غشا و فرایندهای غشایی، سال
تعداد صفحات: ۷
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.<\div>

۲Fabrication of polyvinylidenefluoride–co–hexafluoropropylene (PVDF–HFP) electrospun membranes for air gap membrane distillation
نویسنده(ها): ، ، ،
اطلاعات انتشار: دومین همایش ملی غشا و فرایندهای غشایی، سال
تعداد صفحات: ۶
The main hindrance for membrane distillation (MD) is the availability of optimized design of MD membrane that can produce high surface hydrophobicity, high porosity, appropriate pore sizes and a higher flux. In the past few years, application of electrospun nanofiber has gained intensive attention for MD membrane and exhibit promising results. The aim of this study was to fabricate and optimize Polyvinylidenefluoride–co–hexafluoropropylene (PVDF–HFP) membranes. Response surface methodology (RSM) based on Box–Benkhen design was utilized to design the experiments. The objective was to prepare optimized electrospun nanofiber membrane with mean pore size in the range of 300–500nm, maximum porosity and hydrophobicity. Scanning electron microscopy (SEM), geniometer, gravimetric method and air gap MD (AGMD) setup were used tocharacterize the resultant PVDF–HFP membranes. The optimum electrospinning conditions were obtained to be 23wt%concentration, 13 kV voltages, 24 cm tips to collector distance and 0.4 mL\h flow rate. At the optimal operating condition the fabricated membranes were characterized with mean pore size, porosity and contact angle of 435 nm, 81% and 1410, respectively. The synthesized membrane was applied in desalination via air gap membrane distillation, in which a water flux of 13.6 Lh–1m–2 with a salt rejection ratio of 99.7% was obtained.<\div>
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