Study On Decontaminability And Oil-water Separation Properties Of Nano/Micro-fiber Membrane

In this dissertation, the decontaminability of nano/micro-fiber membrane wasevaluated through studying on their properties of cleaning dust and oil dirty. Therelationship between the properties of cleaning dust and dust level, wiping pressure, theinfluence of thickness of membrane and diameter of fiber on the dust-cleaning propertiesof electrospun fiber membrane, the oil absorption properties and oil-water separation effectof membrane were discussed. Then in order to improve the properties of cleaning oil dirty,modified electrospun PSU micro-fiber was prepared by polyblending, and a goodrepeatable usability was achieved.Dust-cleaning properties of nano/micro fiber membrane: coal powder and flourwere chosen as dust dirt, and then cleaning method and device were devised, to discuss theinfluence of dust level and wiping pressure on dust-cleaning properties. Then thedust-cleaning properties of electrospun nano/micro-fiber membrane was tested, andcompared with cleaning clothes on the market. The results prove that, under the samewiping pressure, the more of dust level, the higher of the dust removal rate; under the samedust level, the higher of the wiping pressure, the higher of the dust removal rate, anddust-cleaning properties can be improved by increasing the wiping pressure properly.The thickness of membrane and diameter of fiber were chosen to discuss thedust-cleaning properties of electrospun fiber membrane. The softness of membrane decreasesas the thickness of membrane becomes higher. When the wiping pressure is very low, the dustremoval rate of electrospun PSU fiber membrane with high thickness is noticeably low; as thewiping pressure becomes higher, the dust removal rate of samples improved; and the dustremoval rate of electrospun fiber membrane is higher than that of Non-woven sample withsimilar softness. As the diameter of electrospun fiber becomes lower, the dust removal rate ofelectrospun fiber membrane becomes higher, and the number of fibers leaving on the glassbecomes fewer, the length of fiber leaving on the glass becomes smaller too, and thedust-cleaning properties of nano-fiber membrane is the best. Oil dirty-cleaning properties of nano/micro fiber membrane: soybean oil, liquidparaffin, white oil were chosen as the representative of vegetable oil, mineral oil, crude oilto study the oil absorption and oil-water separation properties of nano/micro-fibermembrane, to evaluate its degreasing effect comprehensively. The results prove that, theadsorbing speed of electrospun PSU fiber membrane and cleaning clothes on the marketwere very quickly, being closed to the maximum oil absorbency within1min. The oilabsorption of electrospun fiber with minor diameter and high specific surface area is higherthan other cleaning clothes on the market, and the oil absorption of electrospun nano-fibermembrane is higher than that of electrospun micro-fiber membrane. The oil-waterseparation properties of electrospun fiber membrane is better than that of cleaning clotheson the market, and the oil remove rate from oil/water emulsion of electrospun nano-fibermembrane is near to50%. The next is micro-fiber membrane, the knitting micro-fiber clothis the worst.To improve the oil-water separation properties of Electrospun PSU fiber membrane,Electrospun PSU/SiO2composite fiber was prepared. A kind of lipophilic and hydrophobicnano-SiO2was mixed in spinning solution to improve the oil-water separation properties ofmembrane by enhancing the lipophilicity and hydrophobicity of fiber. The results provethat, the nano-SiO2could be uniformly dispersed in spinning solution by ultrasonictreatment for5min, and the mixed solution of PSU and nano-SiO2could preparecontinuous uniform fiber by electrospinning under determined spinning conditions. Themaximum oil absorbency of Electrospun PSU/SiO2composite fiber membrane was fromabout13g/g to about28g/g, and the superficial static state contact angle to water-dropincreased from107.4°of Electrospun PSU fiber membrane to137.8°, the oil remove ratefrom oil/water emulsion increased from about40%to about93%. And ElectrospunPSU/SiO2composite fiber membrane had a good repeatable usability.