Robust and renewable hierarchical silica nanowires grown on a stainless steel mesh for oil/water separation

Porous filters with selective wetting properties offer a more effective route for separating oil and water than traditional industrial processes. However, developing durable structures for emulsion purification remains a challenge. Herein, we present a filter comprising a stainless steel mesh decorated with silica nanowires, which is highly resistant to fouling (almost 0° water contact angle and 166° underwater oil contact angle) and demonstrates excellent separation efficiency and reusability. The nanowire filter is particularly suited for separating n-hexane/water emulsions, where the oil phase could be completely separated by the filter. In addition, it demonstrates remarkable resistance to acid (pH 2 for 10 days), salt solution (37 days), butane flame, and abrasion, indicating its applicability in harsh environmental conditions. By combining the advantages of low-cost production, excellent separation, and enhanced durability, this nanowire filter holds significant potential for oil/water separation applications.