Facile approach to develop durable and reusable superhydrophobic/superoleophilic coatings for steel mesh surfaces

Oil spills on the surfaces of bodies of water are now a great concern as they affect marine creatures and the ecosystem. Therefore, a facile technique for removal of oil from water is of much interest. In this study, superhydrophobic and superoleophilic coating is synthesized on stainless steel mesh via chemical etching using a mixture of FeCl₃ and HCl followed by treatment with hexadecyltrimethoxysilane. Surface morphology analysis shows the presence of flower like microstructures on the surface after treatment. Superhydrophobic and superoleophilic properties have been achieved on stainless steel mesh with water static contact angle of 167° ± 3°, water tilting angle of 6° ± 1°, and oil static contact angle of nearly 0°. The coating shows excellent thermal, chemical and mechanical stability. Kerosene-water and hexane-water mixtures were successfully separated via a simple filtering process using coated steel mesh with a separation efficiency of more than 98%. This approach can be implemented on any shape or size of stainless steel mesh and will have industrial applications.