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Carbon nanotube-based membranes with special wettability are ideal candidates to handle oily wastewater. However, their applications are limited owing to the low film-forming ability, unsatisfactory mechanical stability, and insufficient reusability. Herein, this work presents an effective strategy for fabricating a flexible multiwall carbon nanotubes (MWCNTs)/ultralong MnO2 nanowires (UL-MnO2–NWs) hybrid membrane, as well as its application in emulsion separation. In this strategy, the dispersed carbon nanotubes were obtained by acid treatment of agglomerate MWCNTs, and the UL-MnO2–NWs were prepared by a hydrothermal route. Then, the MWCNTs/UL-MnO2–NWs hybrid membrane with an improved mechanical property and excellent reusability was fabricated via vacuum-filtration of MWCNTs and UL-MnO2–NWs suspension. The obtained hybrid membrane shows superhydrophilicity with a water contact angle of 0° and underwater superoleophobicity with an oil contact angle of 152°. It can effectively separate both surfactant-free and surfactant-stabilized oil-in-water emulsions with permeances up to 4900 L m–2 h–1 bar–1 and high separation efficiency of greater than 99.7%. More importantly, the as-prepared sample shows superior recyclability, antifouling property, and excellent mechanical and chemical stability, which match well with the requirements for treating the real emulsions. As a result, this hybrid membrane can be a potential candidate for practical application in water-in-oil emulsion separation.
Yue et al. (Sun,) studied this question.