In this study a new PSf/pebax/F-MWCNTs nanocomposite membrane was prepared, characterized and used for nanofiltration of oil/water emulsion. For this purpose, the porous PSf support was prepared and then a thin layer of pebax as selective layer was coated on it. The effect of adding 0.5, 1 and 2 wt% of functionalized multiwall carbon nanotubes (F-MWCNTs) on the morphology and separation properties of resulting membranes were studied systematically. Prepared membranes were analyzed using SEM, FTIR, contact angel, tensile strength and TGA analyses. FTIR results approved the stabilization of F-MWCNTs in membrane matrix. SEM showed the membrane surface was defect free and F-MWCNTs particles were not agglomerated. Increasing F-MWCNT up to 2 wt%, increased hydrophilicity, tensile strength and ther- mal stability. Separation of oil/water emulsion was investigated at pressure range of 10–20 bar The high- est permeate flux was obtained for 0.5 wt% F-MWCNTs loading while the sample containing 2.0 wt% F- MWCNTs showed the best oil rejection at all studied pressures. Results revealed that oil rejection was decreased with pressure. Finally, flux recovery, irreversible and reversible fouling was analyzed for all the prepared membranes at all pressures.

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