Fabrication of photo-Fenton self-cleaning PVDF composite membrane for highly efficient oil-in-water emulsion separation

Abstract

The anti-fouling performance of membranes is an important performance in the separation of oil/water. However, the membrane with anti-fouling performance will also have surface scaling phenomenon when it runs for a long time. Therefore, there is still a great demand for stain-resistant membranes with good self-cleaning ability and high flux recovery rate. Based on this, this paper firstly prepared a hydrophilic membrane with carboxyl group and carboxyl ion by blending poly(ethylene-alt-maleic anhydride) (PEMA) and polyvinylidene fluoride (PVDF), and then prepared a self-cleaning composite membrane by in situ mineralization of β-FeOOH particles on the surface of the membrane for efficient oil-in-water emulsion separation. A large number of –COOH/COO⁻ and β-FeOOH particles on the membrane surface make the composite membrane have strong hydrophilic properties (WCA = 20.34°) and underwater superoleophobicity (UOCA = 155.10°). These composite membranes have high separation efficiency (98.8%) and high flux (694.56 L m⁻² h⁻¹ bar⁻¹) for soybean oil-in-water emulsion. Importantly, the as-prepared membrane shows excellent flux recovery rate (over 99.93%) attributed to the robust photo-Fenton catalytic activity of β-FeOOH, and the β-FeOOH is chemically bonded to the as-prepared membrane, which makes the as-prepared membrane have good reusability. This work provides hope for the application of self-cleaning membranes in the construction of anti-fouling membranes for wastewater remediation.