Hydrothermal fabrication of robustly superhydrophobic cotton fibers for efficient separation of oil/water mixtures and oil-in-water emulsions

In this study, superhydrophobic and superoleophilic cotton fibers are fabricated by simple one-step hydrothermal route followed by modification with silane. The obtained fibers show selective sorption ability to the oils from water, high sorption capacities, excellent recyclability, and quick sorption rate. The fibers also exhibit outstanding superhydrophobic stability under a variety of corrosive solutions and hot water, which enables it application for the separation of the oils from harsh water environments. Moreover, the superhydrophobic fibers in conjunction with a tube (valid tube area: 0.5 cm(2)) that connected to a vacuum system (vacuum pressure: 0.03 MPa) is capable of collecting up to 200 times its self-weight in gasoline within 20 s. The coated fibers can also selectively harvest oils from oil/water mixtures under extreme turbulent condition. More importantly, the coated fibers can separate micron sized oil droplets from oil-in-water emulsions with a high separation efficiency (transparency for solvent oils: >91%) that is beyond what can be obtained by most traditional separation methods. All these performances make the as-prepared cotton fibers ideally suited for the oil-spill cleanups and water purification. (C) 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.