Facile fabrication of SWCNT film-based superhydrophobic cotton fabrics for oil/water separation and self-cleaning

Abstract

With the increase of oily waste, oil-water separation has become an urgent and difficult task. However, the current challenge is to fabricate such efficient membrane materials for oil-water separation. Herein, superhydrophobic single-walled carbon nanotubes (SWCNTs)/cotton fabric (CF) was prepared via a dry process. In which the ultrathin SWCNT films with a low content of hydrophilic groups were prepared by a facile floating catalyst chemical vapor deposition method and directly deposited on CF without solvent dispersion. The obtained SWCNT@CF was further treated by 1 H,1 H,2 H,2 H-perfluorooctyltriethoxysilane (POTS). Due to the synergistic effect of SWCNTs and POTS, the POTS-modified SWCNT@CF displayed excellent superhydrophobicity with a water contact angle（WCA）of ∼163.3°, and consequently can be further used as a membrane for oil-water separation. These superhydrophobic fabrics have high oil/water separation efficiency (99.2% for dichloromethane/water) and high oil flux (28.71 ×103 L·m−2·h−1 for dichloromethane/water). Even after 25 separation cycles, oil/water separation efficiency and oil flux maintain 98.8% and 25.15 × 103 L·m−2·h−1, respectively. In addition, it exhibits high separation efficiency (∼99%) for water-in-oil emulsion. Moreover, under extreme environmental conditions, the contact angle of the obtained POTS-modified SWCNT/CF was maintained at ∼155°, keeping stable superhydrophobicity. This reported preparation strategy of superhydrophobic fabrics is environmentally friendly, low cost, sustainable, and easy to scale up, thereby exhibiting great potential in practical applications.