Bio-inspired and green fabrication of superhydrophobic materials with good robustness, stability and flame retardancy for oil-water separation based on waste cotton

Recently, more and more attention has been paid to bionic superhydrophobic materials for treating the intricate oil-water mixture system for the sake of resource recovery and environmental protection. With the in-depth development of research, scientists have been committed to pursuing the superhydrophobic materials via the economical, clean, and environmentally friendly methods. The current bio-inspired innovation of this paper concentrates on constructing superhydrophobic porous materials based on green, low-cost, and renewable waste cotton via in situ hydrothermal growth and solution immersion strategy. As anticipated, the water contact angle (WCA) of the prepared superhydrophobic cotton materials reaches 158°, exhibiting good self-cleaning ability and oil/water separation efficiency (99% ± 1%). Compared with pure cotton, superhydrophobic cotton materials also possesses elevated flame retardancy. In addition, after 300 cm abrasive paper friction tests, 10 times oil-water separation tests, 7 days of acid and alkali immersion tests (pH=1, 13), salt water immersion tests, and UV irradiation tests, as-prepared cotton materials can still maintain excellent superhydrophobic properties. On the basis of this work, an effective, facile and environmentally-benign avenue for fabricating the super-hydrophobic materials has been exploited that displays the promising applications in fields of waste cotton recycling, oil spill treatment and oil/water separation.