High flux filtration medium based on nanofibrous substrate with hydrophilic nanocomposite coating.
A novel high flux filtration medium, consisting of a three-tier composite structure, i.e., a nonporous hydrophilic nanocomposite coating top layer, an electrospun nanofibrous substrate midlayer, and a conventional nonwoven microfibrous support, was demonstrated for oil/water emulsion separations for the first time. The nanofibrous substrate was prepared by electrospinning of poly(vinyl alcohol) (PVA) followed by chemical cross-linking with glutaraldehyde (GA) in acetone. The resulting cross-linked PVA substrates showed excellent water resistance and good mechanical properties. The top coating was based on a nanocomposite layer containing hydrophilic polyether-b-polyamide copolymer or a cross-linked PVA hydrogel incorporated with surface-oxidized multiwalled carbon nanotubes (MWNTs). Scanning electron microscopy (SEM) examinations indicated that the nanocomposite layer was nonporous within the instrumental resolution and MWNTs were well dispersed in the polymer matrix. Oil/ water emulsion tests showed that this unique type of filtration media exhibited a high flux rate (up to 330 L/m2-h at the feed pressure of 100 psi) and an excellent total organic solute rejection rate (99.8%) without appreciable fouling. The increase in the concentration of surface-oxidized MWNT in the coating layer generally improves the flux rate, which can be attributed to the generation of more effective hydrophilic nanochannels for water passage in the composite membranes.
Wang
Xuefen
X
Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400, USA.
Chen
Xuming
X
Yoon
Kyunghwan
K
Fang
Dufei
D
Hsiao
Benjamin S
BS
Chu
Benjamin
B
D004655:Emulsions / Q000737:chemistry; D005648:Fuel Oils / Q000032:analysis; D008422:Materials Testing; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry*; D010539:Permeability; D011142:Polyvinyl Alcohol; D014462:Ultrafiltration / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000295:instrumentation* / Q000379:methods*
D004655:Emulsions; D005648:Fuel Oils; D008567:Membranes, Artificial; D014874:Water Pollutants, Chemical; D011142:Polyvinyl Alcohol