Robust membranes with tunable functionalities for sustainable oil/water separation

Efficient separation of various oil/water emulsions using amphiphilic, hydrophobic/oleophilic, or hydrophilic/oleophobic-based membrane materials have attracted considerable attention in the past few decades. For sustainable and facile management of emulsions, the exploitation of membrane technology is the most dominant technique due to its comparative simple handling and operations. The high surface areas, controllable pore size, nanoscale interconnected pore structures, and chemical surface modification, superwetting membranes are the most versatile and promising tool for the destabilization of oil/water emulsions. From the current research efforts on membrane materials with superwettability, another mature system arose with superwettability and became a more vibrant area, which encompasses the theme of superhydrophobic/superoleophilicity, and superhydrophilic/superoleophobic under liquid or in the air and super aerophobic/super aerophilic under the liquid. In this review, we present an overview of hydrophilic and hydrophobic wettabilities, followed by the idea of a chemical method for effective oil/water separation. Furthermore, the detailed explanation of the membrane type of base materials (organic and inorganic) is summarized. Then, the membrane-based separation of oil/water and hydrocarbon contaminated water is discussed in detail. In conclusion, this review will clarify the recent development in the design and construction of membrane material in a specific composition, proper size, surface morphology, and generate a good interest in the realms of oil/water separation as well as environmental issues.