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Electrospun membrane surface by (a) 4 wt%, (b) 6 wt% (c) 8 wt% (d) 12 wt% Polyacrylonitrile (PAN) solution, respectively. Scale bar: 2 µm
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Oily waste water flux of Composite Membrane in Comparison with Commerial filters
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High-flux Low-fouling three-tier Membrance filters (Chu):
Conventional water filtration membranes (e.g. Ultra-filtration, Reverse Osmosis, et al.) were often manufactured by using an immersion casting method, capable of generating porous structures during fabrication. Thin film composite membranes have been developed based on conventional membrane processing technology (nonporous top layer was coated on micro-porous mid-layer). However, the controllable surface porosity (which is proportional to the flux) in the micro-porous mid-layer is limited (~ 30 %).
Electro-spinning has been used to fabricate nano-fibrous and highly interconnected porous membranes for air filtration and biomedical applications. We have now developed a new application to use the electro-spun membrane as a micro-porous mid-layer in water filtration. Unique features of high surface porosity (> 70 %) as well as high bulk porosity can lead to higher fluxes than conventional composite membranes. The ease in controlling the nanofiber diameter from ~100 nanometers to few micrometers can provide a new “platform” for ultra-thin coating and the mechanical integrity to couple the nonporous top-layer with the electro-spun mid-layer.
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