Excellent oil-water separation under external pressure: Controllable critical pressure and separation efficiency by well-designed hierarchical mesh structure

[Display omitted] •Excellent oil-water emulsion separation under external pressure.•Controllable critical pressure and separation efficiency by designed mesh structure.•Built a model of hierarchical mesh structure and confirmed by experiment.•Mesh microstructure affects energy barrier and critical pressure.•Provides theoretical guidance for the design of mesh structure. With the increase of oily wastewater, the improvement of separation efficiency for oil-water emulsion under external pressure is an urgent task to resolve. As an important indicator for the separation result, the separation efficiency is affected by the wetting transition and external pressure. In this contribution, we built a model of hierarchical mesh structure and analyzed the effect of the space of mesh microstructure and the solid fraction of mesh nanostructure on energy barrier and critical pressure, which was further confirmed by experiment. The influences of external pressure on separation efficiency were also investigated experimentally, verifying the reasonability of critical pressure. This work provides guidance for designing and choosing the mesh structure applied in the separation of oil-water mixture under external pressure to get an excellent process efficiency and separation efficiency.