Breakthrough in controlling membrane fouling and complete demulsification via electro-fenton pathway: Principle and mechanisms

Abstract

The emulsified oil wastewater would cause profound damage to the environment if not appropriately treated. The difficulty in deforming the interfacial film of emulsions is still a key challenge for the emerging bio-inspired superhydrophilic membrane, resulting in membrane concentrates that need post-processing. Furthermore, the membrane fouling deeply inside membrane pores via complicated physicochemical interactions is hardly real-time mitigated by the conventional self-cleaning strategies, and remains another challenge for long-term operation. To break through these limitations, a novel electro-Fenton assisted superhydrophilic membrane was first designed, and the underlying self-cleaning and demulsification mechanisms were thoroughly unveiled. Extremely high permeation flux (2258.5 L ·m−2h−1) and flux recovery ratio (98.1%) were achieved. Both reversible and irreversible fouling could be well controlled through the real-time degradation of foulants and electrostatic repulsive forces between the negatively charged membrane and foulants. Strikingly, the surfactant could be decomposed by the in situ generated •OH, leading to the destruction of thermodynamic stability of oil-in-water emulsions. Consequently, the emulsions were transformed to large-sized floating oil and dispersed oil, achieving highly effective oil/water separation. These features manifest the attractive potential application in emulsion treatment, leading to a new era of radical-assisted super-anti-foluing and demulsification driven by electro-Fenton process.