Fabrication Of Biomimetic Superwettin Surface On Metal Sieves By Electrodeposition And Their Application In Oil/Water Separation

With the expans ion of the industrial scale and the growth of population, the ever-increasing industrial oily wastewaters are generated in diverse industrial technologies, such as the petrochemical, transportation, leather, and steel, the direct discharge of which will bring about harm to the environment and people’s health. Therefore, oil/water separation is an important field for improving the environment and resource recovery. According to the different wettability of oil and water on the surface, biomimetic surface with superhydrophobic/ superoleophilic properties or superhydrophilic/underwater superoleophobic properties can separate oil from water efficiently. In this work, we fabricated superhydrophobic/superoleophilic CP/SC mesh、 superhydrophilic/underwater superoleophobic Cu（OH）₂ copper foam、and superhydrophobic/superoleophilic Cu（OH）₂/NDM copper foam and designed oil/water separation devices to research the oil/water separation properties of the as-prepared materials.The coaxial cable-like stainless steel ?bers@conducting polymer（polyaniline or polypyrrole） with special hierarchical micro-nano-scale roughness are successfully synthes ized by using a facile, inexpens ive and controlled pulse electro-polymerization method（PPM）. Conjugated with stearoyl chloride（SC） through acylation reaction, the obtained meshes exhibit both superhydrophobic and superoleophilic properties with the water contact angle of 154° and the oil contact angle of 0°.It can be used to separate a series of oil/water mixtures like gasoline, diesel, etc. with separation effciency as high as 98%. The separation efficiency remains high after 25 times use（99.9% for hexane/water mixture）. More importantly, the obtained meshes keep ultrastable superhydrophobicity and high separation efficiency in long-term storage, ultrasonic treatment, even under extreme environment conditions of strong acidic, alkaline, hyperhaline and oxidizing solutions, owing to their self-adaption aging protection and antioxidant properties. The corrosion dynamic rate, which for the obtained mesh is 1/60 lower than that of bare stainless steel mesh, is proved by electrochemical measurements. Therefore, this work provides an alternative to current separation meshes and is promis ing in various important applications.Electrochemical deposition for the growing of rough copper particles on 3D structured copper foam was employed to enhance the roughness and mechanical strength of copper foam. And then, Cu（OH）₂ nanowires thin film has been fabricated on the copper foam surface via an easy, fast, cost-efficient and environmentally friendly chemical oxidation method. The resultant surface exhibits a water contact angle of 0o and underwater oil contact angle of 165o, showing excellent superhydrophilic/underwater superoleophobic properties. After modification with NDM, superhydrophobic/superoleophilic Cu（OH）₂/ NDM copper foam with water contact angle of 154o and oil contact angle of 0o was obtained. The results indicate that the porous structure of initial copper foam was optimized after 60 minutes electrodeposition, which lead to an appropriate and comprehensive oil/water separation properties for of the Cu（OH）₂ copper foam and Cu（OH）₂/NDM copper foam. Inspired by two-way channels and all kinds of induction phenomenon in daily life, we proposed a two-way channel and wettability response separator by combination of two complementary brushes（superhydrophilic Cu（OH）₂ copper foam and superhydrophobic Cu（OH）₂/NDM copper foam）. This novel device can achieved a continuous, highly purity, and high-flux oil/water separation, showing widely application in oil/water separation. More importantly, the 120 min deposition superhydrophobic Cu（OH）₂/NDM copper foam can separate water in oil emuls ion efficiently and fast. In addition, the as prepared Cu（OH）₂ copper foam shows stable and excellent separation properties after impaction and friction.