Superhydrophilic and Underwater Superoleophobic Pvdf-Pes Nanofibrous Membranes for Highly Efficient Surfactant-Stabilized Oil-in-Water Emulsions Separation

Abstract

Deep oil-water emulsions separation is a challenging task for treating oily wastewater. Herein, a superwettable nanofibrous membrane was successfully fabricated using the integrated method of electrospinning, microwave-assisted growth, and in-situ polymerization. The membrane possessed superhydrophilicity and underwater superoleophobicity due to the presence of hierarchical rough structures and hydrophilic particles and polymers. The nanofibrous membrane exhibited robust oil-water separation performances for surfactant-free oil-in-water emulsions and different types of surfactant-stabilized emulsions (e.g., SDBS, CTAB and Tween80) solely under the effect of gravity. The membrane achieved a separation efficiency of >99.94% for surfactant-free oil-in-water emulsions with a flux of 3563.0 L m-2 h-1. The efficiency was above 98.90% with a flux of 1112.5 L m-2 h-1 for SDBS-stabilized oil-in-water emulsion solely under the effect of gravity. The membrane exhibited great long-term oil-water separation efficiencies above 97.0%. Moreover, the membrane showed remarkable stability and can maintain the underwater superoleophobicity under different harsh conditions, which is key for large-scale oily wastewater treatment applications.

Keywords: Electrospun, Nanofibrous membrane, superhydrophilic, Underwater Superoleophobic, Oil-in-water emulsion separation