Fabrication of sepiolite-based super-hydrophobic stainless steel mesh for enhanced stability and high efficiency oil-water separation

As one of natural nano-clay material, sepiolite is easy to modify to obtain low surface energy, which has great potential in the field of superhydrophobicity application. A novel superhydrophobic micro nanofibers (CSEP/OTS) were prepared by grafting long alkyl chains onto organic activated sepiolite fibers (CSEP) by using octadecyltrichlorosilane (OTS) and tetraethylorthosilicate (TEOS). Then, the superhydrophobic sepiolite-based mesh (SSM-SHSEP) was prepared by spraying a mixed suspension of CSEP/OTS and epoxy (EP). Owing to the excellent chemical and physical resistance of sepiolite, epoxy and stainless steel mesh, the prepared mesh exhibits superior robustness and high stability. As the amount of CSEP/OTS increased, the mesh turned from hydrophobic (pristine mesh, WCA = 133.9°) to superhydrophobic (when EP: CSEP/OTS = 1:1.5, WCA = 153.6°). The screened mesh can be an effective tool for separating different oil-water mixtures (reached up to 97.3%). Furthermore, the coated mesh exhibited remarkable reusability (approximately 50 cycles),excellent corrosion resistance (pH from 1 to 13), and distinguished durability (20 cycles of sandpaper abrasion test). All these outstanding performances of superhydrophobic sepiolite-based mesh confirmed that it can be widely used in oil-water separation and thereby showed great potential in large-scale industrial applications.