Construction of superhydrophilic/underwater superoleophobic polydopamine-modified h-BN/poly(arylene ether nitrile) composite membrane for stable oil-water emulsions separation

Oil/water emulsion separation in harsh environments remains a big challenge. Herein, a double layered nanofibrous composite membrane was developed by assembly of polydopamine-modified hexagonal boron nitride (h-BN-PDA) onto a poly(arylene ether nitrile) (PEN) nanofibrous mat. Owing to the synergistic effect of a h-BN-PDA skin layer and a PEN nanofibrous mat supporting layer, as-prepared composite membrane exhibited high thermal stability, corrosion resistance, and superhydrophilic/underwater superoleophobic property. Consequently, the PEN composite membrane showed good antifouling performance and a high rejection ratio (>99.0%) for various oil/water emulsions. After 10 cycles, the separation flux of PEN composite membrane still reached 588.1 L/m 2 h under the operating pressure of 0.04 MPa. Furthermore, the PEN composite membrane could still achieve high separation efficiency and high flux in high-temperature (65 °C) and strongly corrosive conditions (pH = 1-13). Therefore, the stable and efficient h-BN-PDA/PEN composite membrane showed potential application for treating oily wastewater in harsh environments.