Stearic acid treated polypyrrole-encapsulated melamine formaldehyde superhydrophobic sponge for oil recovery

Abstract

Oil spillage poses a serious threat to the marine ecosystem and the environment. This has led to an increasing demand for oil recovery and the quest for effective hydrophobic/oleophilic sorbents for oil-water separation. Herein, we developed polypyrrole (PPy) encapsulated melamine formaldehyde (MF) sponge treated with stearic acid (SA) to obtain a superhydrophobic SA/PPy/MF sponge. The SA/PPy/MF sponge characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy shows that smooth struts of MF sponge get covered with PPy and further SA treatment affords an increased surface roughness and superhydrophobicity which is completely absent in the case of pristine MF sponge treated with either PPy or SA itself. The SA/PPy/MF sponge exhibits contact angles of ~ 170° and 0° by a sessile water and oil droplet on the sponge surface, respectively. Importantly, the SA/PPy/MF sponge demonstrated excellent superhydrophobicity over the entire pH range with absorption capacities reaching up to ~ 70–90 times for various oils from oil-water mixtures.