Preparation And Property Of Hydrophobic/Oleophilic Oily Wastewater Treatment Materials

The amount of oily wastewater generated by human life and industrial activities has continued to increase,causing tremendous damage to the natural environment and various types of living things on the planet,especially the marine life,and at the same time bringing serious losses to the economic development.Therefore,how to separate the oil/water mixtures economically and efficiently is an urgent need for the environment and energy security.In this paper,the smart PS fibrous membrane with pH-responsive wettability for the separation of immiscible oil/water mixture and the carbon nanotube/reduced graphene oxide spherical aerogels capable of reducing the viscosity of crude oil for the high-efficiency adsorption of crude oil were prepared,respectively,which are significant in both theoretical research and practical application.1.The bead-liked porous PS fibrous membrane was prepared by electro-spinning according to the principle of phase separation caused by non-solvent.After treated by two-step pretreatment on the bead-liked porous PS fibrous membrane,UV-grafting reaction was carried out using a hydrophilic-hydrophobic monomer solution mixed in a certain ratio to form a polymer layer with switchable wettability on the surface of PS fibrous membranes.Highly hydrophobic PTFOA and pH-responsive PDMAEA can make the wettability of the as-prepared PS fibrous membrane convert reversibly between superoleophilicity and underwater superoleophobicity with changes of the pH.It can be seen that the as-prepared PS fibrous membrane can easily separate a series of oil or organic solvents,such as hexane,iso-octane,hexadecane,liquid paraffin and plant oil,from the oily wastewater,and the maximum flux can reach 10186.8 L m-2 h-1 for hexane,and the separation efficiency under the driving force of gravity is>99.2%.In addition,the prepared PS fibrous membrane is applied to the self-designed T-tube device,which can realize continuous dynamic oil/water separation.2.The solar-assisted carbon nanotube/reduced graphene oxide spherical aerogels for high-efficiency crude oil adsorption were prepared by the combination of freeze-drying and CVD method.The GO films cross-linked by CS were assembled to form the micro-channels with central divergence under the extrusion of ice crystal.This structure greatly shortens the diffusion path of crude oil inside the aerogel,which is beneficial to the rapid adsorption of crude oil.CS/GO was reduced at 900℃ to form the N-doped RGO,which exhibits a good hydrophobic/oleophilic property(WCA=140°,OCA≈0°).The good wettability can effectively increase the diffusion rate of crude oil.CNTs grown on the surface of RGO with Ni as the catalyst have strong absorption capacity for sunlight with a wavelength range of 200-2500 nm,as well as the graphene,therefore,the N-CNT/RGO spherical aerogels have the excellent photo-thermal conversion effect,which can heat the surrounding crude oil from 20 ℃ to～100 ℃ and significantly reduce its viscosity from～105 mPa s to～102 mPa s,thus solving the problem that the crude oil with high viscosity has poor fluidity and it is difficult to clean and collect efficiently.