Superamphiphilic and underwater superoleophobic membrane for oil/water emulsion separation and organic dye degradation

Over the past few decades, oily water and soluble contaminants have increased from offshore oil accidents, oil-bearing wastewater emissions and oil exploration. This causes enormous damage to the ecosystem and environment. Developing superhydrophilic and superoleophobic materials has therefore received much interest due to their potential in oil/water separation. In this study, we fabricated a TiO2/Co3O4/graphene oxide composite membrane which possesses superamphilicity in air, underwater superoleophobicity, underoil superhydrophobicity as well as photocatalytic properties. A matrix of TiO2 nanocluster-based stainless steel mesh (TiO2 SSM) possesses benign superwetting behavior and good flexibility. A heterojunction of the TiO2/Co3O4/graphene oxide composite is coated onto the TiO2 SSM via vacuum deposition. The underwater oil contact angle and underoil water contact angle of the resulting membrane are both greater than 150 degrees. The resulting film can segregate various oil/water emulsions with efficiencies of >99.5%, and provides favorable photodegradation efficiency of Congo red under simulated solar irradiation. The membrane exhibits excellent reusability after 10 consecutive cycles, and good physical and chemical stability. The membrane hence possesses potential in sewage and effluent disposal.