Facile fabrication of superhydrophobic SiO2-coated mesh used for corrosive and hot water/oil separation

Abstract

Oil pollution has been a worldwide problem. Most of the superhydrophobic materials lose their superhydrophobicity when exposed to hot water (e.g., >50 °C) and strong corrosive liquids. Herein, we demonstrated superhydrophobic SiO2-coated meshes that can repel hot water (about 92 °C) and strong corrosive liquids, which can be used for gravity-driven separation of oil–water mixtures in hot water and strong acidic and salty environment. In addition, the as-prepared robust meshes can separate a series of oil/water mixtures with the separation efficiency larger than 98.3%. The mesh still maintained separation efficiency above 98.0% after 40 cycles of separation. So the robust superhydrophobic meshes developed in this work have potential application in the actual oily wastewater treatment. The SiO2-coated meshes could keep its superhydrophobic property even in harsh conditions and separate oils from corrosive solutions (1M HCl and 3.5 wt% NaCl) and hot water effectively.