Multilayer Network Membranes Based on Evenly Dispersed Nanofibers/Co3O4 Nanoneedles for High-Efficiency Separation of Micrometer-Scale Oil/Water Emulsions

Ultrawetting membranes have enabled great progress in oil/water separation and have helped to address global industrial wastewater pollution and marine oil spills. However, there are few reports of 3D multilayer network membranes that can be easily prepared, and give efficient separation in micro- and nanoscale oil-in-water emulsions. A membrane is designed for emulsion separation; it consists of ultralong (over 10 mu m) sodium titanate nanofibers as the selective layer and a jungle-like Co3O4 nanoneedles mesh as the support layer. This mesh shows superhydrophilicity in air and low-adhesive superoleophobicity under water. This membrane gives 99.9% separation efficiency and good permeation flux, and has great advantages in the separation under gravity of oil-in-water emulsions with droplet sizes larger than 400 nm. The results of this work provide a new method for designing ultrathin, efficient, and durable separation membranes with a 3D multilayer network structure.