On demand oil/water separation enabled by microporous ultra-thin aluminum foil with asymmetric wettability

The novel metal membranes with multifunctionality and adaptability have become the new strategies in the field of oil/water separation. Distinct from other multifunctional membranes, the novel metal membranes that are less time-consuming and cost-efficient can perform on-demand oil/water separation in the large scale separation environment. However, obtaining an ultra-thin metal membrane with multifunctionality and adaptability for application remains a challenge. Taking advantage of both the atypical localized etching and solution dipping method, a novel MUAF membrane was prepared in our study. With the vertical capillary effect and the papillary-like micro structures, this novel membrane displays asymmetric wettability and achieves the efficient separation of light and heavy oil/water mixed solutions. The whole separation process was driven by gravity, without requiring extra energy. The mechanism of oil/water separation was also investigated by the intrusion pressure. Our work presents a simple and rapid method that uses ultra-thin AF to fabricate a novel asymmetric wettability metal membrane that is promising for future application in the large scale separation environment. This membrane also has application potential for oil storage and transportation.