3D Superhydrophobic Sponge Coated with Magnesium Hydroxide for Effective Oil/Water Mixture and Emulsion Separation

One of the main challenges for the treatment of oily wastewater is emulsion separation. However, emulsions are generally more stable and difficult to separate. Herein, we report a facile strategy for the fabrication of monolithic oil/water separation materials by modifying melamine sponge with magnesium hydroxide (MH) coating, which can effectively separate immiscible oil/water mixtures and surfactant-stabilized emulsions. Its demulsification efficiency for the surfactant-stabilized emulsions can exceed 99.7%. In particular, the separation flux in a continuous emulsion separation system driven by a low-power pump can reach as high as 6.7 X 10(4) L m(-2) h(-1). MH particles coated on the surface of the sponge is one of the key factors for the formation of superhydrophobic surfaces and provide abundant adsorption sites for oil. Moreover, it was found that the surfactant added during the MH synthesis process not only affects the surface charge of MH but also interacts with the surfactant in the emulsion, which can promote instability and breaking of the oil/water interfacial film of emulsion.