Construction of Polytetrafluoroethylene nanofiber membrane via continuous electrospinning/electrospraying strategy for oil-water separation and demulsification

Oily wastewater treatment is an arduous and urgent global problem. Electrospinning has wide applications in construction of high-efficiency oil-water separation membranes. Herein, electrospinning and electrospraying technology were combined to construct a Polytetrafluoroethylene (PTFE) nanofiber membrane (NFM) with multileveled structure for oily wastewater treatment. The separation performance (driven by gravity) of the NFM to oil-water mixture was studied. In addition, the demulsification performance of the NFM to water-in-oil surfactant-stabilized emulsions (W/O SSEs) under gravity and oil-in-water surfactant-stabilized emulsions (O/W SSEs) at 0.5 bar were studied subsequently. The results showed that the flux of the 9% D-H-PTFE to the oil-water mixture reached 4909 L m(-2) h(-1), with a separation rate of 99.99%; the flux to the CCl4 W/O SSE reached 1867.93 L m(-2) h(-1) with the separation rate of 98.46%. The flux to the CCl4 O/W SSE was 122 L m-(2) h(-1) and the separation rate was 98.40% in multiple cycles. Therefore, these NFMs are expected to be practically applied to a low-pressure driven membrane separation system for preliminary separation of different types of oily wastewater.