Antifouling poly(phenylene sulfide) membrane with an amphiphilic surface for efficient oil/water separation

Poly(phenylene sulfide) (PPS)-based membranes hold great promise in the disposal of oily wastewater. However, their inherent lipophilic chemical structure and the pronounced concentration polarization effect will lead to serious fouling during operation. Herein, a PPS membrane with an amphiphilic surface (aPPS) is designed and fabricated by assembling phytic acid (PA) and perfluorohexanoic acid (PFHA) on the PPS membrane to obtain a superior antifouling property. PFHA as the hydrophobic domains are dispersed on a continuous hydrophilic PA layer at a molecular scale, which achieves the decrease of apparent surface energy with preserving the underwater superoleophobicity. Owing to the low intermolecular interaction and small contact area with oil, the amphiphilic surface exhibits nearly zero adhesion force towards oil, and accordingly, the aPPS membrane shows a low flux decline ratio (<15%), a high flux recovery ratio (∼100%) at high permeance (∼4100 L m−2 h−1 bar−1) and desired oil rejection (>98%). Moreover, the aPPS membrane exhibits stability under pH 3–11 and the temperature from ambient temperature to 80 °C, which demonstrates a promising potential for the practical separation of oil/water emulsions.