Efficient chemical etching procedure for the generation of superhydrophobic surfaces for separation of oil from water

The water pollution due to the oil spillage and the regular addition of organic contaminants from industrial wastewater has emerged as a major threat to the marine and human life. The generation of efficient superhydrophobic surfaces has received special attention to achieve efficient separation of the oil and organic contaminants from the water. Herein, a superhydrophobic surface was coated on stainless steel by using the facile 2 step process. In the first step, the surface roughness and the oxide functionalities were generated on the surface of the stainless steel by treating with the sulfuric acid. In the second step, it was functionalized with the octadecyltrichlorosilane (ODTCS). The functionalized surface was confirmed by the Fourier-transform infrared spectroscopy, Raman spectroscopy, and the scanning electron microscopy. The functionalized stainless steel surfaces have displayed superhydrophobic and superoleophilic behavior. The water was strongly repelled by the surface whereas the non-polar organic component was rapidly spread on the surface. The superhydrophobic behavior was evident from its high water contact angle of 166.8˚. The developed superhydrophobic surface has displayed an excellent capability to separate the non-polar component from water. The separation efficiency was found more than 99% for the separation of various non-polar organic components from the water.