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 degrees, 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.