Natural Highly-hydrophobic urushiol@TiO2 coated cotton fabric for effective oil-water separation in highly acidic alkaline and salty environment

A natural acid-alkali-salt resistant urushiol@TiO2 coated cotton fabric with a high water contact angle of 146.1 +/- 0.3 degrees was designed employing a facial immersion method. The as-prepared urushiol@TiO2 coated cotton not only has excellent stability toward UV irradiation and high temperature, but also exhibits great resistance to mechanical abrasion and acid-base solutions with various pH values. More importantly, while the pristine cotton fabric was penetrated and even destroyed by acid or base solutions immediately, the urushiol@TiO2 structures protected the coated cotton from penetration by high acid (10 M H2SO4 for 70 min and 1 M H2SO4 for more than 18 h) and high base (10 M NaOH for 70 min and 1 M NaOH for more than 18 h) solutions. The sharp contract indicates the potential of urushiol@TiO2 coated fabric to be used in some extreme conditions. Therefore, the as-prepared urushiol@TiO2 coated fabric was found to not only act as a high performance filter to separate oil-water mixtures with superior reusability, but also retain high separation efficiency separating oil-water mixtures in highly acidic (10 M H2SO4), alkaline (10 M NaOH), and salty (saturated NaCl) environments, as well as oil-in-water and water-in-oil emulsions. The modified fabric is environmentally friendly, and easy to fabricate with low cost, offering promising potential applications in resolving the serious issues of oily wastewater treatment and anti-corrosion protection.