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Magnetic textile with pH-responsive wettability for controllable oil/water separation

Yan, Tao, Zhang, Taiheng, Zhao, Guoqing, Zhang, Chongyang, Li, Caifeng, Jiao, Feipeng
Colloids and surfaces 2019
fabrics, hydrophilicity, hydrophobicity, iron oxides, magnetic materials, magnetism, nanoparticles, oil spills, oils, pH, sewage, sustainable technology, temperature, titanium dioxide, wettability
More and more attention has been paid to materials with special wettability for the potential application in oil/water separation and oil-spill treatment. In this work, we presented a simple, efficient, and environmentally friendly method to develop a magnetic textile that could achieve switchable wettability by changing the pH value of the surface. The textile was fabricated by a mixture of Fe3O4 nanoparticles and dodecylamine (DDA)-modified TiO2 with high permeate flux, high separation efficiency and good stability. The Fe3O4/DDA-TiO2 textile showed its superhydrophobicity and superoleophilicity for neutral water (pH = 7), while the textile became superhydrophilic and underwater superoleophobic for acidic water (pH = 2).The as-prepared textile was investigated using eight different density oil/water mixtures. The results showed that the as-prepared textile possessed excellent separation efficiency (>99%) and high oil flux of about 9400-13000 L h-1 m-2, water flux of about 6400-6700 L h-1 m-2 and good reusability. Meanwhile, the textile can maintain superhydrophobic under high temperature (˜170 °C), which significantly indicated its practical application in harsh environment. Because of its magnetism, the textile can be recovered and removed by magnets. We believe that this work may provide a number of potential application, such as microfluidic device, oil recovery and sewage purification.