A facile preparation of superhydrophobic halloysite-based meshes for efficient oil-water separation

A superhydrophobic halloysite-based mesh was facilely prepared by spraying epoxy/hexadecyltrimethoxysilane-halloysite nanotubes (HDTMS-HNTs) on stainless steel mesh. The as-prepared mesh was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical contact angle meter (OCA). The HNTs modified by HDTMS not only enhanced surface roughness, but also endowed hydrophobicity of the mesh. The mesh, with a static water contact angle of 154° and a sliding angle of 1.5°, was applied to separate a series of oil-water mixtures, such as n-hexane-water, isooctane-water and petroleum ether-water, with high separation efficiency of over 98%. The mesh still kept separation efficiency approximately 98.5% even after 25 separation cycles for n-hexane-water mixture separation. More importantly, the mesh is durable enough to withstand heat, chemical and mechanical challenges, such as hot water, strong alkaline, strong acid and sand abrasion, and high hydrostatic pressure. The as-prepared mesh will be a promising material in oil-water separation, because of the simple, economical and easily scalable preparation method and the excellent separation performance in radical oil-water separation.