| With the deepening of the concept of green,healthy,and sustainable development,a series of environmental pollution and ecological problems caused by oil leakage and oil wastewater discharge need to be solved urgently.Therefore,there is an urgent need for a highly efficient separation method to treat oily wastewater.Membrane separation technology has been widely used in the field of oil-water separation due to its advantages of high separation efficiency and simple operation.In particular,hydrophobic electrospun carbon fiber membrane has been regarded as one of the best candidates for oil-water separation due to its advantages of good thermal stability and resistance to organic solvents.In order to further improve the hydrophobicity of the electrospun carbon fiber membrane,different methods were applied to construct micro-nano structures on the surface of the electrospun carbon fiber,and the superhydrophobic and superoleophilic carbon fiber membranes were prepared.The main research results are as follows:(1)Polydopamine(PDA)was coated on the surface of electrospun carbon fiber(CF)by dip-coating method,playing a role of chelation and reduction in the process of electroless plating,so as to deposit copper nanoparticles on the surface of the fiber.It was then fluorinated by perfluorooctyltriethoxysilane(POTS),and finally the superhydrophobic electrospun carbon fiber(F/Cu/PDA/CF)membrane was successfully obtained.The results show that after dip-coating and electroless plating,the smooth CF surface becomes rough and irregular ellipsoidal copper nanoparticles appear.In addition,compared with CF and F/PDA/CF membrane,F/Cu/PDA/CF membrane has good non-aqueous wettability and oil-water separation performance,and its water contact angle(WCA)can reach 158.5°,leading to the superhydrophobic property.In addition,the prepared F/Cu/PDA/CF membrane shows good environmental stability under different conditions(high and low temperature,ultraviolet irradiation and immersion in organic solvent).(2)A series of superhydrophobic carbon fiber(F/Zn O/CF)membranes with different hydrothermal times were successfully prepared by in-situ growth of Zn O nanorods on the surface of electrospun carbon fibers by hydrothermal method to construct micro-nano structures and subsequent fluoridation reactions with POTS.The results show that the Zn O nanorods are uniformly deposited on the surface of CF,and the POTS has successfully modified the membrane sample.Besides,the prepared F/Zn O/CF membranes have good superhydrophobicity due to the effect of needle-like nanostructure and low surface energy.The obtained F/Zn O/CF-3 membrane has excellent water contact angle(WCA,159.7°)and excellent oil-water separation efficiency(>99%),when the hydrothermal reaction time was 3 h.In addition,the obtained F/Zn O/CF-3 membrane demonstrates excellent environmental stability in a series of environments such as high/low temperature and organic solvents.(3)On the basis of the study in the previous chapter,a new type of superhydrophobic and superoleophilic electrospinning carbon fiber membrane with rod-like Zn O nanorod structure and low surface energy was prepared by in-situ growth of Zn O nanorods assisted by surfactants for the separation of oil-bearing wastewater.The results show that the addition of surfactant can modify the surface morphology and non-aqueous wettability of the fiber.Among them,the obtained superhydrophobic F-Zn O@CF-SDS with good water contact angle(WCA,163.5°)has a high oil flux(3531 L/(m~2·h)).Furthermore,the separation efficiency of F-Zn O@CF-SDS membrane for oily wastewater remains above 99%,which has good recyclability.Meanwhile,F-Zn O@CF-SDS membranes show good environmental stability under different conditions(such as ultraviolet irradiation,high and low temperature,organic and salt solvents,etc.). |
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