Nature-Inspired Superwetting Membranes for Emulsified Oily Water Separation

Nature-inspired superhydrophilic and underwater superoleophobic membranes have garnered significant attention due to their promising potential for separating emulsified oily water and addressing water security issues. The exceptional wettability imparts spontaneous water permeability and oil repellency to membranes, accelerating water filtration, enhancing oil isolation, and reducing membrane fouling during the process, thereby achieving fast and efficient oil-water separation. Over the past decade, a series of groundbreaking studies on nature-inspired superwetting membranes have propelled oily water separation technology into a transformative phase of development. In the subsequent phase, people still face the challenge of evolving superwetting membranes with the dual capabilities of purifying water and recovering oil from particularly surfactant-stabilized emulsions to achieve sustainable resource utilization and zero liquid discharge. In this Perspective, we briefly review recent advances in superwetting membranes, emphasizing their advantages, bionic principles, design concepts, fabrication methods, and separation performance for various types of emulsified oily water. Additionally, we present membrane-based strategies for simultaneous water purification and oil recovery from emulsified oily water. Finally, we identify current bottlenecks and propose future direction in this area, focusing on the development of next-generation superwetting membranes for comprehensive separation and zero discharge of true oily water at an industrial scale.