Facile fabrication of underwater superoleophobic SiO 2 coated meshes for separation of polluted oils from corrosive and hot water

Abstract

Abstract Separation of oils from water becomes a challenging global task due to the frequent oil spill accidents and expanding industrial oily waste water. Here, we introduced a facile one-step spraying coating method to prepare synergistic superhydrophilic–underwater superoleophobic SiO2 meshes for removal of oils from water. The underwater superoleophobic SiO2 meshes were then used to investigate gravity driven separation of a series of oils from water, where only the water was allowed to permeate through the mesh while the oils were repelled on the mesh surface. Separation efficiency up to 99.0% could be achieved with the coated meshes for the kerosene/water mixture. In addition, the coated meshes still retained underwater superoleophobic properties after 50 separation cycles with the separation efficiency larger than 98.0%. Moreover, the SiO2 coated meshes showed excellent environmental stability under a series of harsh conditions, which were utilized for separation of polluted oils from corrosive and active water, such as strong acidic, salt aqueous solutions and even hot water with the separation efficiency above 98.0%. Thus, such synergistic superhydrophilic–underwater superoleophobic SiO2 coated meshes might be a potential candidate for water body restoration, especially oily seawater.