Lotus Leaf-Inspired Corrosion-Resistant and Robust Superhydrophobic Coating for Oil-Water Separation.

Abstract

With daily oil consumption approaching 100 million barrels, the global demand continues to generate significant quantities of oily wastewater during oil extraction, refining, and transportation, and the development of effective oil-water separation technologies has become crucial. However, membrane corrosion is a challenge under the harsh conditions involved. Here, we are inspired by the lotus leaf to create a corrosion-resistant and robust superhydrophobic membrane using a general spraying method. By using this spraying process to apply the Graphene@PDMS heptane dispersion onto the mesh substrate, we create a biomimetic corrosion-resistant and robust superhydrophobic stainless steel mesh (SSM). The modified SSM can still maintain superhydrophobic properties after soaking in a strong acidity solution (pH = 1), robust alkalinity solution (pH = 14), or NaCl solution (15 days), which demonstrates excellent chemical stability. Moreover, the modified SSM shows strong mechanical stability during ultrasonic treatment for 2 h. The superhydrophobic SSM can be used to separate various kinds of oils from water with high flux and separation efficiency. It shows a high flux of 27,400 L·m^-2·h^-1 and high separation efficiency of 99.42% for soybean oil-water separation using 400-mesh SSM. The biomimetic modified SSM demonstrates great potential for oil-water separation under harsh conditions, which gives it promise as a candidate in practical applications of oil-water separation.