Oil-water separation device based on super-hydrophobic material with multi-scale surface structure

A buoyancy-adaptive oil-water separation device is developed based on the prepared oil-water separation materials with a micro-nano hierarchical structure. This device can achieve the efficient recovery of diesel oil pads in the process of salt cavern construction without an external power source. The surface structure of superhydrophobic materials and the wettability of droplets on their surfaces are characterized. Then the separation mechanism is theoretically analysed. In addition, the brine breakthrough pressure and the separation efficiency of the device are studied considering the different surface structures of the separation materials. The mesh number and the layer number of separation materials are explored to determine their effects on the breakthrough pressure. It is found that this pressure increases with an increasing mesh number, but the influence of the screen layers is weak. Furthermore, the mesh number and the number of cycle separations that affect the separation efficiency are investigated. The results show that the sieve hole is smaller when the mesh number is larger, and the volume flow rate of diesel oil is thus reduced. Therefore, the screen mesh number should be reasonably selected based on the actual needs. The results of the cyclic separation test indicate that the separation material has good reusability. After 30 cycles of recycling, the separation efficiency of the device can still reach 90.1 ± 1.7%. (paper)