Super high flux oil/water separation and efficient separation of water-in-oil emulsions by a versatile superhydrophobic multi-walled carbon nanotubes coating

Abstract

This study presents a fabrication method of superhydrophobic coating for efficient oil/water separation application from modified multi-walled carbon nanotubes (MWCNTs) and epoxy resin. Exceptional superhydrophobic (CA = 155.5°, SA = 4.6°) and superoleophilic (CA ≈ 0°) behaviors were demonstrated by spraying the superhydrophobic MWCNTs coating onto 250# stainless steel mesh (SSM). Their separation efficiencies were as high as 98.5 % for CCl4/water mixtures, 97.2 % for chloroform/water mixtures, 98.6 % for gasoline/water mixtures, 99 % for xylene/water mixtures, and 92.5 % for petroleum ether/water mixtures, respectively. Gravity-driven separation of CCl4/water and chloroform/water mixtures achieved high oil fluxes at 77023.6 L⋅m−2⋅h−1 and 55267.2 L⋅m−2⋅h−1, respectively. Additionally, water-in-oil emulsions were effectively separated with efficiencies exceeding 99.5 %. The superhydrophobic MWCNTs coating in this study offers a versatile solution for high flux oil/water separation and efficient separation of water-in-oil emulsions.