A robust and repairable copper-based superhydrophobic microfiltration membrane for high-efficiency water-in-oil emulsion separation

Through the preparation method, super-wetting property and its application in emulsion separation, it provides comprehensive insights about the copper-based superhydrophobic microfiltration membrane, thereby inducing a new emulsion separation mechanism, and demonstrating an efficient oil-in-water emulsion separation function performance. [Display omitted] •The as-prepared membrane has extremely high separation efficiency (above 99.975%).•Copper-based microfiltration membranes expand the choice of materials for efficient separation of water-in-oil emulsions.•The inorganic binder aluminum phosphate was used to enhance the mechanical properties.•Rapidly self-assemble surface modification octadecanethiol (ODT) is the basis for reversible repair. The micro-/nanohierarchical super-wetting filter materials with low energy consumption, low-cost and high-efficiency have attracted tremendous attention. Moreover, traditional emulsion separation materials based on micro-/nanohierarchical structure are easy to be irreversibly damaged due to poor mechanical properties. In this work, a copper-based superhydrophobic microfiltration membrane was fabricated based on simple spraying process and short time self-assemble surface modification method. Only driven by gravity, the membranes maintained excellent water-in-oil emulsion separation performance with the efficiency higher than 99.975%, even after 10 separation cycles, the efficiency is still higher than 99.95%. After 50 sandpaper abrasion cycles, the membranes still displayed excellent separation efficiency through a simple re-modification process. The superhydrophobic microfiltration membranes also had the ability to resist acid and alkali. Robust and copper-based superhydrophobic microfiltration membranes with reversible repair property provide new ideas for the selection of stable emulsion separation materials, and have more advantages and potentials in practical applications.