Modification of 3D polyacrylonitrile composite fiber for potential oil-water mixture separation

Abstract

In this study, a two-dimensional (2D) microporous electrospun polyacrylonitrile (PAN) fiber mat was converted into a three-dimensional (3D) mesoporous fiber scaffold via a simple gas foaming technique with a solution of aqueous sodium borohydride (NaBH4). The 3D PAN fiber was coated with ZnO nano-flowers via a facile one-pot hydrothermal process. The 3D PAN/ZnO fibers were rendered modified into hydrophobic or oleophilic through subsequent treatment with dodecyltriethoxysilane (DTEOS). A modified 3D composite was successfully applied for the absorption of oils with a significant sorption capacity for a series of common oils and organic solvents. Interestingly, absorbed oil with in the 3D fiber composite was easily drained by simple mechanical squeezing. The modified hydrophobic 3D PAN/ZnO composite exhibited an excellent oil sorption capacity compared to the 2D PAN/ZnO composite. The oil sorption capacity of the 3D composite was 4 times higher for low density organic solvents and 2 times higher for high density, viscous oils compared to the 2D composite fiber. The effective oil sorption capacity of the 3D composite rendered it as a promising sorbent candidate for oil spill cleanup and oil-water purification.