Superhydrophobic northern tooth-like ZnO nanosheets on stainless steel mesh for oil-water separation

2D nanosheets, with their unique shape, possess an increased surface area and active sites for interactions with liquid molecules, making them highly effective absorbents. This study introduces a novel hierarchical Northern Tooth-like zinc oxide (ZnO) nanosheet growth on stainless steel (SS) mesh. The growth is achieved via heterogeneous nucleation during immersion in alcoholic solution of zinc acetate dihydrate and diethanolamine, which was followed by a stearic acid (STA) modification. The process of zinc ions (Zn²⁺) hydrolysis and anisotropic growth on the SS mesh, facilitated by its surface roughness and controlled reaction conditions, leads to the formation of tooth-like ZnO nanosheets. STA, by bonding its carboxyl groups with Zn²⁺ ions, reduces surface energy, promotes self-assembly, and stabilizes nanosheet morphology. The coated SS mesh showed superhydrophobicity with a water contact angle (WCA) of 162 ± 2° and a sliding angle (SA) of 3°. SEM confirmed Northern Tooth-like ZnO nanosheet growth on SS mesh. The superhydrophobic SS mesh achieved 99 % separation for petrol and 92 % for vegetable oil. The permeation fluxes were recorded at 700 ± 50 L/m²·h for the petrol and 135 ± 50 L/m²·h for the vegetable oil. SS mesh remained superhydrophobic after undergoing 70 cycles of adhesive tape peeling tests, 20 cycles of sandpaper abrasion tests, and multiple torsion, bending, and folding motions. It also withstood exposure to heat and both alkaline and acidic environments. Furthermore, the mesh demonstrated a remarkable self-cleaning ability. The proposed formulation for creating a superhydrophobic mesh is promising for oil-water separation applications.