Dual-bionic superwetting gears with liquid directional steering for oil-water separation

• Published in: Nature communications Vol. 14; no. 1; p. 4128
• Main Authors: Liu, Zhuoxing, Zhan, Zidong, Shen, Tao, Li, Ning, Zhang, Chengqi, Yu, Cunlong, Li, Chuxin, Si, Yifan, Jiang, Lei, Dong, Zhichao
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12-07-2023; Nature Publishing Group; Nature Portfolio
• Subjects: 147/135; 3-D printers; 639/166/898; 639/166/988; 639/301/923/1030; 639/301/923/614; 639/638/169/896; Antifouling substances; Bionics; Design; Efficiency; Emulsions; Gears; Humanities and Social Sciences; multidisciplinary; Oil spills; Overflow; Science; Science (multidisciplinary); Separation; Steering; Surface energy; Surface properties; Synergistic effect; Topology; Wastewater
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-39851-1

Developing an effective and sustainable method for separating and purifying oily wastewater is a significant challenge. Conventional separation membrane and sponge systems are limited in their long-term usage due to weak antifouling abilities and poor processing capacity for systems with multiple oils. In this study, we present a dual-bionic superwetting gears overflow system with liquid steering abilities, which enables the separation of oil-in-water emulsions into pure phases. This is achieved through the synergistic effect of surface superwettability and complementary topological structures. By applying the surface energy matching principle, water and oil in the mixture rapidly and continuously spread on preferential gear surfaces, forming distinct liquid films that repel each other. The topological structures of the gears facilitate the overflow and rapid transfer of the liquid films, resulting in a high separation flux with the assistance of rotational motion. Importantly, this separation model mitigates the decrease in separation flux caused by fouling and maintains a consistently high separation efficiency for multiple oils with varying densities and surface tensions.
Developing efficient separation methods for oily wastewater holds significant global importance. In this study, the authors combine supewettability and bio-inspired topological structures to demonstrate a dual-bionic superwetting gear system with liquid directional steering to achieve oil-water separation.