Preparation and performance study of superhydrophobic/superoleophilic stainless steel-based SiO₂/PDMS/FEVE separation...

To achieve the rapid recovery of spilled oil and high-efficiency oil-water separation in marine oil spill accidents, a one-step spraying method was adopted in this study. The blend of KH570-modified nano-SiO₂ particles and polydimethylsiloxane/fluorocarbon resin (PDMS/FEVE) was sprayed onto a 304 stainless steel mesh to fabricate a high-durability oil-water separation mesh. The surface morphology and composition of the as-prepared separation mesh were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Raman spectroscopy. The oil-water separation efficiency, permeation flux and cyclic stability of the mesh were tested via a self-assembled oil-water separation experimental device. The durability of the separation mesh was further evaluated by weight-loaded friction test, tape-peeling treatment and saline immersion test. The results show that the water contact angle of the fabricated Stainless Steel-based oil-water separation mesh reaches 162°, enabling rapid separation of oil-water mixtures with different viscosities. The separation efficiencies for diesel/water, lubricating oil/water, and hydraulic oil/water mixtures are 99.82%, 99.34% and 99.39%, respectively, while the corresponding permeation fluxes are 43.56 × 10³ L/(m²·h), 3.52 × 10³ L/(m²·h) and 3.92 × 10³ L/(m²·h). After incorporating FEVE into the coating, the separation cycles for both diesel/deionized water mixtures and diesel/seawater mixtures is obviously elevated. The results of saline immersion tests, weight-loaded friction tests and tape-peeling tests demonstrate that the incorporation of FEVE optimizes coating retention capacity and strengthens the interfacial bonding strength among SiO₂ nanoparticles, polymeric binder and stainless steel substrate. The enhanced performance of the stainless steel-based oil-water separation mesh is mainly attributed to the improvement of superhydrophobic/superoleophilic properties on the mesh surface induced by modified nano-SiO₂ particles, as well as the enhanced bonding strength of nanoparticles on the metal mesh substrate provided by fluorocarbon resin.