The Preparation Of Superhydrophobic Materials And Oil/Water Separation Properties's Research

In recent years, more and more serious environmental pollution, especially oil spills and industrial emissions of organic matter caused serious harm to the environment. Several measures were employed to overcome such pollution including oil skimmer, coagulating agent, dispersing agent, in-situ bioremediation and burning. However, these methods focus on cleaning up, and ignore that it may produce secondary pollution on the environment. The using of biomimetic oil/water separation material, not only separates the oil and water away from the mixture of the oil-water, but also can prevent secondary pollution. Biomimetic oil water separation material can be divided into three categories: superhydrophobicsuperoleophilic oil water separation materials, superhydrophilic-superhydrophobic oil water separation materials and intelligent water separation materials. Comparing with the other two separation materials, superhydrophobic-superoleophilic oil-water separation materials is more suitable for large areas of oil-water mixture separation. Mainly includes the following parts:in this dissertation, several superhydrophobic-superoleophilic oil-water separation materials were prepared based on different substrates. The main work of performed in this dissertation is as follows:(1) Using stainless steel mesh as the substrate, superhydrophobic-superoleophilic stainless steel mesh was prepared by electrodepositing Cu nanoparticles on the surface to form micro and nano structures, and then postmodification with low surface energy stearic acid. The surface morphology of the as-prepared superhydrophobic stainless steel mesh is inverstigated by various experimental parameters such as electroplating time, current,electrolplating temperature and electrolyte concentration. The optimal experimental parameters were obtained. Water contact angle and oil contact angle of as-prepared stainless steel mesh are 152° and 0°, respectively. This mesh exhibits good stability as its superhydrophobic properties did not change after 1h ultrasonic irrigation. However, when the mesh was treated with high temperature(200 o C), the hydrophobicity properties decreased suggesting that the materials are not suitable for high-temperature oil-water separation.Besides, The p H scale for its application ranges from 5 to 11. After oil/water separation testing, it was found that the materials could separate a series of oil-water mixture(heavy oil or light oil) quickly and efficiently, and can be reused.(2) Compared to the stainless steel mesh, fabric is breathable, soft, flexible, cheap and ubiquitous. Thus, fabric was choosed as substrate. Firstly, a conductive fiber membrane was coated on the fabric surface by assembling a layer of GO(graphene oxide)/CPAM(cationic polyacrylamide) composite, rapid reduction of GO with sodium borohydride at roomtemperature, Then the Cu nanoparticles was formed on the surface by electroplating get the functionalized fabric with micro and nano structures. Finally, the the functionalized fabric was modified with low surface energy stearic acid to obtain the superhydrophobic-superoleophilic fiber membrane.The surface morphology of the as-prepared superhydrophobic fiber membrane was researched by various experimental parameters such as electroplating time and voltage. The optimal experimental parameters were obtained. Water contact angle of as-prepared fiber membrane is 153°, and oil phase can instantly penetrate into the surface.Besides, the p H range for application is 2-14. Using the material for oil water separation tests,it was shown that the material was quick and efficient for the separating oil-water mixture(heavy oil or light oil), and is stable for reusing.(3) Sponge based on melamine(melamine-formaldehyde foam, MF sponge) not only has the advantage of sponges, and is an ideal fire retardant, which may reducing the risk of fire and explosion in oil-water separation process. MF sponge was firstly assembled with a layer of GO(graphene oxide)/CPAM(cationic polyacrylamide) composite film. Then the MF sponge with GO layer was sequence coated with Cu nano-particles and stearic acid by electrodepositing and postmodification, getting the superhydrophobic-superoleophilic sponges. The surface morphology of the as-prepared superhydrophobic sponges is was affected by electroplating time, and it was found that the best time is 90 min. Water contact angle and oil contact angle of as-prepared sponges respectively is 154° and 0°. The p H scale for its application ranges from 5 to 13. Superhydrophobic MF sponge has the capability of oil-water separation. When superhydrophobic MF sponge dipped into oil-water mixture, the oil was extruded from the sponge by extrusion method or pumping methods. However,superhydrophobic properties of the sponge were damaged after reusing for 8 times by pumping methods.