| With the continuous development of science and technology and the increasing economic level of human life,the oil and water pollution caused by industry and human daily life is becoming more and more serious,and the environment where the oil and water mixture is located is also becoming more and more severe.Therefore,we must carry out the research and development of effective oil-water separation technology,which is not only of great significance to protect the ecological environment,but also needs to realize the recovery and reuse of water resources.The emergence of electrospinning and membrane separation technology provides a new idea for the separation of oil-water mixtures.The preparation process of polymer membranes is simple,the membrane materials are various,the flexibility is good,and the price is cheap.However,the environment where the oil-water mixture exists is getting worse and worse,and the polymer oil-water separation membrane has gradually been unable to meet the needs of effective oil-water separation in extreme environments.Compared with polymer membranes,electrospun ceramic membranes have higher chemical stability and applications under different extreme conditions.However,at present,electrospun ceramic oil-water separation membranes have problems such as poor flexibility and complicated preparation processes.In view of the key problems existing in the application of electrospinning ceramic fiber membrane materials in oil-water separation,this paper combines electrospinning technology with other technical methods.Starting from the preparation process,adjusting the surface structure of the fiber membrane and the wettability of the surface/interface to improve the oil-water separation efficiency of the fiber membrane.The specific research work is as follows:（1）The microsphere structure was constructed on the SiO2 nanofiber by electrospinning and electrostatic spraying,and the microsphere/nanofiber membrane with superhydrophilic and underwater superoleophobic properties was prepared by one-step method.The effect of the ratio between polymer solutions and the spinning time on the microspheres and their oil/water selective wetting characteristics.The selective transport mechanism of ceramic nanofiber membranes for oil/water was analyzed,the application performance of nanofiber membranes in oil in water（O/W）emulsion separation was investigated.The results show that the separation efficiency and antifouling performance of the emulsion can be significantly improved by constructing the microsphere structure on the surface of the fiber membrane,while the separation flux of the membrane is hardly affected.The obtained composite membrane can achieve high-efficiency separation of micron-sized oil droplets in water only under the action of gravity（equivalent driving pressure is about 1 k Pa）,and has stable recycling performance.（2）In order to further improve the durability and reusability of the membrane,we constructed Si O2 NPs on the surface of ordinary electrospun Si O2/PVB fiber membrane by electrospinning technology,and then hydrophobicity modified them with DTCS.The effect of DTCS concentration on the microscopic morphology of the membrane and the selective wettability of the membrane was studied,and the effect of the content of Si O2 NPs on the morphology and structure of the membrane was studied.Benefiting from the micro/nano hierarchical structure and the hydrophobicity of the hydrophobized Si O2/PVB film and the hydrophobic Si O2 NPs bulk,the obtained nanofibrous film exhibits superoleophilic-superhydrophobicity under oil.On this basis,the application of nanofiber membranes in oil-water emulsion separation was further studied.It is found that Si O2 NPs can improve the separation efficiency and anti-fouling performance of nanofiber membranes without affecting the membrane separation flux.The obtained nanofiber membrane can achieve high-efficiency separation of micron-scale W/O emulsions only under the action of gravity.Most importantly,the membrane can be repaired to a certain extent by simple heating after physical damage. |
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