Preparation And Study Of Superwetting Oil-water Separation Materials

In recent years, scientific and technological progress and industrial development not only bring us a lot of benefits, but also bring a lot of trouble. This includes oil/water pollutions, such as offshore crude oil spill, oil leakage of mechanical equipment and edible oil pollution. The above oil/water pollution is not only a waste of resources, but also a threat to our daily life. Research for developing the coping functional materials are being more and more impressive. Until now, various superwetting materials have been produced to separate the oil/water mixture, including superhydrophobic/superoleophilic, superhydrophilic/superoleophobic, and intelligent controllable superwetting materials. However, there are several shortcomings for the existing superwetting oil/water separation materials, such as complex preparation process, expensive raw materials, poor mechanical stability, secondary pollutions to environment, and narrow application range. In order to solve the above problems, we developed several functional materials, which could be used for various oil/water separation. These functional materials have a series of merit, including cheap raw materials, simple fabrication method, and easy recycling properties. Moreover, the cheap raw materials would solve its original detriments to environment. We have these following conclusions:1. The magnetic polymer-based graphene foam(MPG) for oil-water separation was fabricated by the hydrothermal method using polyurethane(PU) sponge. The resulting MPG exhibited superhydrophobicity and superoleophilicity with the water contact angle of 158 ± 1° and the oil contact angle of 0°. A broad variety of oils and organic solvents can be removed from oil–water mixtures under manipulation by a magnet bar with high absorption capacity and selectivity due to its magnetic property. Significantly, the MPG can remain high absorption capacity for oil-water separation after several absorption/desorption-cycles, demonstrating its good reusability. Therefore, the findings of this study offered a facile approach for the cleanup of pollution by crude oil, petroleum products, and toxic organic solvents.2. To develop a simple and efficient way to recycle used cigarette filters, we report on a one-step method for preparing superhydrophobic and superoleophilic cigarette filters for oil/water separation. The robust coating layer on the surface of the cellulose acetate fiber, along with the inherent rough texture of the cigarette filter, could lead to its surface that displayed superhydrophobicity and superoleophilicity. Water droplets can retain in spherical shapes on the modified cigarette filters, while oils were immediately absorbed by the cigarette filters with high absorption capacity. As a result, free oil–water mixtures were separated with efficiency of above 98.0% by the driving force of gravity, and water-in-oil emulsion was also separated with a promising flux of about 2500 L m-2 h-1. The purity of oil for the tested emulsion was above 99.96%, indicating extremely high separation efficiency. This method for the fabrication of the superhydrophobic and superoleophilic cigarette filters would be a good candidate for recycling the solid wastes and developing an economic oil/water separation material to meet emerging needs in practical applications.3. To overcome easy oil fouling and poor efficiency of traditional oil/water separation materials, superhydrophilic and superoleophobic coatings were fabricated by spray casting chitosan-based nanocomposites. The molecular rearrangement of hydrophilic and oleophobic constituents, combined with the hierarchical rough surface structures, enabled a coating with a water contact angle of 0° and a hexadecane contact angle of 157° ± 1°. Hexadecane droplets can easily slide off the dried and water-wetted coating without leaving any obvious oily trailing stains. When the superhydrophilic and superoleophobic CTS-based nanocomposite coatings were applied to oil/water separation, they exhibited excellent antifouling capacity, high separation efficiency and easy recyclability. The superhydrophilic and superoleophobic chitosan-based coating would be a good candidate for the treatment of industrial oil-polluted water and the cleanup of oil spills.