Laser etching enhanced SiO2 deposition to fabricate superhydrophilic/ underwater superoleophobic surfaces for stable oil-water separation

Due to their unique surface characteristics, oil-water separation membranes with superhydrophilic and underwater superoleophobic properties have promising applications in oil-water separation processes. However, the microstructure and chemical composition of the material surfaces are prone to degradation in harsh environments. This article employs nanosecond laser etching to improve the deposition quality of fumed SiO2 for the fabrication of superhydrophilic and underwater superoleophobic separation membranes. Various analytical methods are used to characterize the separation membranes. Nanosecond laser etching creates rough, ripple-like microstructures on stainless steel mesh, which not only enhances the deposition of fumed SiO2 but also minimizes the interaction between solids and oil. This results in improved wetting characteristics and underwater oil repellency, significantly boosting both the performance and durability of the membrane. The prepared separation membrane demonstrated an average separation efficiency of 99.4 % across five different oil-water mixtures, with all separation fluxes exceeding 58,000 L m-2 h-1. After soaking in an acid-base solution for 15 days and undergoing 25 friction tests, the underwater oil contact angle was maintained at 156.3 degrees, demonstrating high separation efficiency and outstanding stability, with significant potential for application, particularly in harsh environments.