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 MnO₂ nanowires, 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.