A simple strategy for developing biomimetic coalescing media with super-wetting and hierarchical-structured papillae for efficient oil/water separation

In the pursuit of environment-friendly solutions for oily wastewater treatment in challenging environments, the demand for efficient coalescing media is greater than ever. This study introduced a biomimetic coalescing medium, engineered to deliver superior oil-water separation through its unique architecture and surface wettability. The composite material features lotus-leaf-like papillae formed by porous Zn(OH)2 microspheres interwoven with ultralong MnO2nanowires, surface decorated with an ultrathin, chemically inert PVDF layer. The fabricated materials possess high surface area, hierarchically porous structure, and hydrophobic/oleophilic properties that are favorable for selective and effective oil droplets' coalescence. The coalescing medium demonstrates outstanding oil-water separation efficiency (over 99%) and water flux (1198 L m-2 h-1), regardless of acidic, alkaline, or saline environments. By paving a new way for the production of biomimetic, high-performance coalescing media, this research advances the practical application of coalescence technology for treating industrial oily wastewater-particularly in harsh operational settings.