Mechanically Robust Fish-Scale Microstructured TiO2-Coated Stainless Steel Mesh by Atomic Layer Deposition for Oil–Water Separation

Recently, inorganic-material-coated separation membranes have been widely applied in the field of oil/water separation due to their advantages of high efficiency and low energy consumption. However, usual preparation methods including electrodeposition, hydrothermal method, sol–gel method, and liquid phase immersion method have complex preparation processes or poor adhesion between coatings and substrates, leading to their poor mechanical stability and limiting their practical application. Herein, a mechanically robust TiO2 coating with a unique fish-scale structure on a stainless steel mesh was prepared by the atomic layer deposition (ALD) technique, which can efficiently separate oil/water mixtures with a high flux of 1.43 × 105 L·m–2·h–1. The separation efficiency can reach more than 99.0% for various oil–water mixtures, and the intrusion pressure for various oils is higher than 1.64 kPa. More importantly, a series of mechanical stability tests, such as friction test, impact test, adhesion test, and kneading test, show that the obtained TiO2-coated stainless steel mesh has excellent mechanical stability. The soaking experiment in 1 M HCl, NaOH, and NaCl corrosion solutions shows that the mesh membrane has good chemical stability. Meanwhile, based on the excellent photocatalytic capacity of the TiO2 coating, the obtained TiO2-coated stainless steel mesh has special self-cleaning and antifouling ability. This work provides an efficient strategy using ALD technology for producing a mechanically robust functional coating separation membrane, which has great practical application value in the field of oil–water separation.