Construction of superhydrophilic and underwater superoleophobic membranes via in situ oriented NiCo-LDH growth for gravity-driven oil/water emulsion separation

The development of superhydrophilic/underwater superoleophobic membrane is significant for purification of emulsified oily wastewater. However, low flux and membrane fouling still remains a challenge. Herein, a sisal-like structured hybrid membrane is prepared through in situ growth of nickel cobalt layered double hydroxide (NiCo-LDH) microcrystals on membrane surface for oil/water emulsion separation. The as-prepared hybrid membrane (CN@pDA@PVDF) exhibits low oil adhesion, outstanding antifouling performance and superhydrophilicity/underwater superoleophobicity. Under gravity driven, the separation experimental results demonstrate the as-prepared membrane can effective separate surfactant-free emulsion (SFE) and surfactant-stabilized emulsion (SSE) with separation efficiency of above 99.4%. Furthermore, with a simple and low cost approach, as well as the significantly enhanced performance, the as-prepared hybrid membrane has bright application prospective in wastewater treatment.