Preparation and Characterization of Stable Superhydrophobic Copper Foams Suitable for Treatment of Oily Wastewater

Abstract

A simple two-stage chemical solution process is reported, to deposit a superhydrophobic film on copper foams with a view to be employed in oil absorption or filtration procedures. The first stage includes the growth of a silver layer to increase micro roughness and the second one evolves the modification of the film using stearic acid. The whole process is time-saving, cost effective and versatile. UV-Vis spectroscopy was employed to determine optimum deposition durations and detect potential film detachments during the synthesis process. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to examine the film structure and elemental analysis. Surface functional groups were detected by Fourier transform infrared (FTIR) spectroscopy. An adherent superhydrophobic silver coating was achieved under optimum deposition durations. A leaf-like structural morphology appeared from silver deposition and spherical, microflower morphologies stemmed from the stearic acid deposition. The influence of process conditions on wettability and the obtained silver film morphology and topography were clarified. Thermal stability at several temperatures along with chemical stability for acidic and alkaline environments were examined. Oil absorption capacity and separation efficiency were also evaluated for the optimum superhydrophobic copper foams. The results showed that the produced superhydrophobic copper foams can potentially be used to oil/water separation applications.