Electrospun Polyacrylonitrile-Fluorinated Polyurethane/Polysulfone Nanofiber Membranes for Oil–Water Separation
Pengju Han, Bo Yu, Yanfei Chen, Gaowei Nie, Kai Wang, Xiaoyan Sun, Xiang Li, Weili Shao, Fan Liu, Jianxin He
Abstract
Electrospun nanofiber membranes exhibit efficient oil–water separation performance, owing to their fine and controllable fiber diameters. However, the three-dimensional dense stacking of nanofibers leads to low porosity, decreasing the oil flux in oil–water separation. Here, a composite nanofiber membrane with a dual-scale structure was designed to achieve a high oil–water separation efficiency and high oil flux simultaneously. In detail, a dense polyurethane/fluorinated polyurethanes (PAN-FPU) nanofiber layer with a fine fiber diameter (150 nm) and a small pore size (3–4 μm) was combined with a fluffy polysulfone (PSF) nanofiber layer with a coarse diameter (1200 nm) and a large pore size (8–9 μm). Using the PAN-FPU nanofiber layer as the inlet layer, modular electrospinning equipment was used to prepare dual-scale nanofiber membranes with a high oil–water separation efficiency and high flux in one step. When the fiber ratio of PAN-FPU/PSF was 1:2, the resulting composite nanofiber film could achieve a separation efficiency of 99.58% and an oil flux of 4630 L m –2 h –1 for an oil–water mixture. For a water-in-oil emulsion, the separation efficiency and oil flux reached 99.37% and 1124 L m –2 h –1, respectively. In addition, the separation efficiency and flux of the biscale nanofiber membrane were simulated by establishing a fluid model, and the simulation results confirmed that the fiber membrane had excellent separation performance. Dual-scale composite nanofiber membranes have potential applications in the field of oily wastewater treatment and locomotive filters compared with monolayer membranes.