Bioinspired interlaced wetting surfaces for continuous on-demand emulsion separation

Abstract

Maintaining high separation performance during continuous emulsion separation remains a challenge. Herein, based on biomimetic coupling ideas, hole array interlaced wetting surfaces (HAIWSs) and mastoid array interlaced wetting surfaces (MAIWSs) were prepared by laser processing, electroless silver deposition, thiol modification, and spraying for on-demand emulsion separation. When the separation is going on, randomly moving emulsion droplets are prone to being captured by holes or mastoids due to interlaced wettability. Under this unique interface behavior, the occurrence of filter cake and pore clogging is reduced, thus achieving both high efficiency (~99.5 and ~99.3%). Meanwhile, the high flux can also be maintained (~3212 and ~3458 L m^-2 h^-1). Significantly better than surfaces without pores or mastoid structures. Further, the as-prepared surfaces also exhibit excellent recyclability. After 50 separation cycles, optimized HAIWS and MAIWS still maintained high efficiency (~96.2 and ~95.8%) and high flux (~3042 and ~3164 L m^-2 h^-1), exceeding other surfaces without hole or mastoid structure. Notably, complex physical/chemical cleaning processes are avoided. Besides, even in harsh conditions, HAIWS and MAIWS still maintain excellent stability. The above strategy provides a novel mechanism for effective on-demand emulsion separation and is expected to encourage the creation of new-class separation devices for oily wastewater treatment in industry.