High-adhesion superhydrophobic SiC/SiO2-g-OTES fibrous membrane fabricated by covalent grafting for efficient water-in-oil emulsion separation

Industrial oily wastewater and water-in-oil (W/O) emulsions are difficult to treat because of the high stability of dispersed water droplets, while conventional superhydrophobic membranes often suffer from poor durability and performance degradation under harsh operating conditions. Therefore, the development of robust superhydrophobic membranes with high separation efficiency and long-term stability remains a significant challenge. To address these issues, a high-adhesion superhydrophobic SiC/SiO 2 fibrous membrane was fabricated through covalent grafting of octyltriethoxysilane (OTES) onto a hierarchical ceramic framework. The abundant surface hydroxyl groups provided active anchoring sites for the formation of a crosslinked polysiloxane network, while the optimized grafting conditions promoted a high-adhesion superhydrophobic state with pronounced liquid pinning behavior, consistent with the Cassie-impregnating regime. The resulting membrane exhibited a water contact angle (WCA) of 153.3° and maintained stable superhydrophobicity after exposure to acidic, alkaline, and high-temperature environments. Benefiting from the synergistic effects of hierarchical pore architecture and interfacial wettability, the membrane achieved separation efficiencies above 98.5% for various W/O emulsions, together with a maximum permeation flux of 1305 L·m −2 ·h −1 at 3.0 bar. In addition, the membrane demonstrated excellent anti fouling performance and long-term operational stability during continuous filtration and cyclic separation tests. This work provides a feasible strategy for engineering high-adhesion Cassie-impregnating wetting interfaces on electrospun SiC/SiO 2 ceramic fibrous membrane and offers a promising route for efficient oil-water separation under harsh conditions.