A novel Cu(OH)2 coated filter paper with superhydrophobicity for the efficient separation of water-in-oil emulsions

A novel filter paper (FP) with superhydrophobicity and superoleophilicity was prepared via adsorption and immersion process for the separation of surfactant-stabilized water-in-oil emulsions. The realization of superhydrophobicity with a water contact angle of 153° benefits from the Cu(OH)2 nanostructure formed on FP and subsequent stearic acid (STA) modification. The three-dimensional network of FP as well as superhydrophobic and superoleophilic property can facilitate the demulsification of emulsified oil, thus the only gravity-driven separations of various water-in-oil emulsions with high oil flux and good recyclability have been achieved. The superhydrophobic FP can be massively applied in emulsion separation due to its facile preparation and superior performance.