Plant cell-inspired superhydrophobic PEEK nanofiber aerogel with superior mechanical properties for high-temperature oil-water separation

Petroleum-contaminated wastewater and industrial effluents are increasingly threatening ecosystem. Aerogels possess immense potential for oil-water separation with their porous structure and high porosity. However, the inherent brittleness of conventional aerogels severely limits their practical utility under demanding conditions. Nanofiber aerogels (NFA) present a compelling alternative by integrating mechanical flexibility with a resilient 3D porous network. Inspired by the reversible water uptake and loss in plant cells, a superhydrophobic poly ether ether ketone (PEEK) nanofiber aerogel (Si@PEEK NFA) with a three-dimensional (3D) hierarchical cellular structure was constructed through directional freeze-drying and cross-linking. The biomimetic 3D hierarchical cellular structure exhibited exceptional compressive strength, achieved 1.1 MPa compressive stress (ε = 80%) and 80% retention after 100 cycles (ε = 50%). Notably, the Si@PEEK NFA retained stable and durable mechanical properties even in high-temperature solvent. Through hydrolysis-polymerization of methyltrichlorosilane (MTCS), lotus leaf-like nipple structure was constructed on PEEK NFA surface, which conferred excellent organic solvent absorption capacity and recyclability (94% retention after 20 cycles). Simultaneously, Si@PEEK NFA exhibited outstanding emulsion separation capabilities at both ambient and high-temperature, achieved nonane emulsion flux of 6970 L m −2  h −1 (room temperature) and 8200 L m −2  h −1 (90 °C), with separation efficiency both exceeding 99%. This work provides an effective strategy for the fabrication of mechanically robust nanofiber aerogels for emulsion separation under harsh condition.