Preparation And Application Of Superhydrophobic Oil-water Separation Materials

Oil spills occur from time to time during the mining,transportation,and storage processes of the petroleum industry.Electronics,textiles,leather making,printing and dyeing,food,kitchen and other industries also produce a large amount of oily/organic solvent wastewater.If oily wastewater is allowed to discharge,it will not only affect the environment,but also harm human health and interests.Effective means and methods are urgently needed to solve these problems.Traditional measures for treating oily wastewater have many shortcomings,such as low efficiency,high cost,or secondary pollution.In recent years,new oil-water separation materials have been continuously developed.For example,superhydrophobic materials that mimic the special wetting mechanism on the surface of the lotus leaf are used in the process of oil-water separation,showing better performance and effects.However,the current preparation methods of these new materials are costly and complex,and are not suitable for use in large-scale continuous processes.This work is dedicated to the research and development of lowcost and high-efficiency oil-water separation materials suitable for long-term use in batch and continuous processes.The synthesis and modification of polyurethane foam and the modification of metal copper mesh were studied respectively,and their application performances for intermittent oil-water separation and continuous oil-water separation were analyzed and tested.Synthesis,modification and application test of polyurethane foam:In this study,firstly,polyurethane foam was synthesized by polyol and isocyanate,and it has a good three-dimensional porous structure by scanning electron microscope(SEM)analysis.Then through the oxidative self-polymerization of dopamine,the polydopamine was loaded on the surface of nano-copper oxide in an alkaline environment,and then the pretreated copper oxide,n-hexadecylamine,and polyurethane foam were put together to prepare a superhydrophobic foam through a one-step reaction.The foam was characterized by SEM,Fourier Transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),and water contact angle tester(WCA).The surface was loaded with uniform nanoparticles,and the water contact angle was significantly increased,reaching more than 153°.It had good selective adsorption in oil-water mixtures and could be used in the separation of various oil and water with high absorption capacity and recovery rate,it had good recyclability,and could still maintain good separation ability after 50 cycles.Modification and application of metal mesh:The 350 mesh copper mesh was selected,and a superhydrophobic copper mesh was prepared simply and quickly through a two-step reaction.First,the metal copper mesh reacted with ammonium persulfate in an alkaline solution to be oxidized to produce copper ions.The copper ions combined with hydroxide to form copper hydroxide crystals and grown on the surface of the copper mesh,then the hydrophobic copper mesh was obtained by grafting hexadecyltrimethoxysilane onto the surface of the copper mesh.The modified copper mesh was tested and analyzed by SEM,FTIR,XRD,WCA tester,etc.Its water contact angle could reach 155°,and it was self-cleaning.It could separate oil and water with a simple gravity device.The separation efficiency was above 93%,and the separation efficiency did not decrease after 100 times of use.And it could maintain high stability in various concentrations of salt solutions,acid and alkali solutions.The modified copper mesh was an excellent separation material when treating oily wastewater.This paper successfully prepared superhydrophobic polyurethane foam and superhydrophobic metal copper mesh.Both materials were suitable for intermittent and continuous oil-water separation process operations,but the former was more suitable for batch processes,and the latter was more advantageous for continuous processes.Compared with the previous complicated methods and processes,the materials prepared in this work had low cost and excellent efficiency and were expected to be widely used in the oil-water separation process.