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

Abstract

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 9400–13,000 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.